Brian, any tests done on plaster walls? I have 2X4 walls with plaster (button board) on both sides. My ever-changing plan is to remove the plaster from the theater side of the wall and add a 2" top and bottom plate to the theater side of the room and then 2X4 studs to the theater side of the room, creating a staggered stud wall. Insulate with R19 fiberglass insulation+5/8" sheetrock+GG+1/2" SR. Staggered joints on the layers of SR w/ both layers taped. This to all the walls and possibly the ceiling. This is a converted garage so there is only one common wall to the rest of the house. The rest being outside walls w/ stucco on the outside.

Would you treat the other side of the common wall? GG+5/8" SR? Would you do anything different other than maybe using 2 layers of 5/8" SR? Any thoughts on the door. Steel, solid wood, or something else?

Thanks!

You mean like plaster/gg/drywall? Yes, we've done tests in our lab on assemblies such as that. Also with another material that you paint onto a surface and plaster over. Both work very well, but moving to a staggered stud wall is preferable if the pain of plaster removal is not too great. One of the beauties of GG is that you can add it to basically any existing wall + more drywall and get a good wall. However, decoupled GG walls do offer improved performance.

stucco on the outside is good, it's heavy. My childhood home lost 10 tons of stucco that had been built up over the years to probably 100-200 pounds of vinyl siding back in the day, and the result was ALOT more noise in the house. I remember watching all that stucco getting trucked away ... man that was alot of cement.

You would do well to treat the other side of the wall, it'll definitely raise the performance of your assembly. If cost becomes an issue, you can use 50% GG on both sides of the wall and do better than 100% GG on one side of the wall, though not as nifty as 100% gg on both sides.



I recommend starting with some heavy exterior door, and perhaps upgrading the seals. Steel or wood, mass is the important thing, puond for pound the steel door might outperform.

If you really want a sound-isolation door system, nothing beats communicating doors. Two doors to make an airlock. For a single door, concentrate on the seals.

Brian, any tests done on plaster walls? I have 2X4 walls with plaster (button board) on both sides. My ever-changing plan is to remove the plaster from the theater side of the wall and add a 2" top and bottom plate to the theater side of the room and then 2X4 studs to the theater side of the room, creating a staggered stud wall. Insulate with R19 fiberglass insulation+5/8" sheetrock+GG+1/2" SR. Staggered joints on the layers of SR w/ both layers taped. This to all the walls and possibly the ceiling. This is a converted garage so there is only one common wall to the rest of the house. The rest being outside walls w/ stucco on the outside.

Would you treat the other side of the common wall? GG+5/8" SR? Would you do anything different other than maybe using 2 layers of 5/8" SR? Any thoughts on the door. Steel, solid wood, or something else?

Thanks!

You mean like plaster/gg/drywall? Yes, we've done tests in our lab on assemblies such as that. Also with another material that you paint onto a surface and plaster over. Both work very well, but moving to a staggered stud wall is preferable if the pain of plaster removal is not too great. One of the beauties of GG is that you can add it to basically any existing wall + more drywall and get a good wall. However, decoupled GG walls do offer improved performance.

stucco on the outside is good, it's heavy. My childhood home lost 10 tons of stucco that had been built up over the years to probably 100-200 pounds of vinyl siding back in the day, and the result was ALOT more noise in the house. I remember watching all that stucco getting trucked away ... man that was alot of cement.

You would do well to treat the other side of the wall, it'll definitely raise the performance of your assembly. If cost becomes an issue, you can use 50% GG on both sides of the wall and do better than 100% GG on one side of the wall, though not as nifty as 100% gg on both sides.



I recommend starting with some heavy exterior door, and perhaps upgrading the seals. Steel or wood, mass is the important thing, puond for pound the steel door might outperform.

If you really want a sound-isolation door system, nothing beats communicating doors. Two doors to make an airlock. For a single door, concentrate on the seals.

Other than QuietGlue and GreenGlue, are there other makers of viscoelastic glue that are cheaper?

as far as i know, GG is the lowest cost material. remember to factor in recommended coverage.

there is an experimental material in our labs that is ~ 1/2 the manufacturing cost, and it outperforms GG over most of the audible range on a damping bench.

but it's not remotely as good in real walls at low frequencies. GG at 50% coverage is flatly a better option.

don't assume that all VE materials are equal, they aren't, nor hardly, nor can a damping bench fully reveal what will happen at low frequencies in a real wall.

the fourth principle of sound isolation is resonance.

In a way, resonance is anti-mass. remember the discussion of mass up above? mass provides resistance to a panel or inner layer of a wall being vibrated by airborne sound. well resonance makes it far easier for airborne sound to vibrate the wall.

Resonance comes in many flavors, which have differing importance. The resonances of different walls aren't the same - each assembly has it's own unique set of mechanics and resonance concerns. A detailed discussion of this from our lab and R&D work is over-due for audio alloys website, but will be intensely technical in nature, and that is a bit beyond the scope of my posts in this thread.

The most important resonances are:

Mass-spring resonance: the low-frequency resonance in any system that isn't a reasonably large single-panel. large single-panels, like a wall that is just drywall screwed to the top and bottom plates some framework, won't exhibit one of these in the audible band.

This is, hands down, the most important factor for almost any wall. Essentially every stud wall has it's overall performance limited here, because at and around this resonance point, the walls performance is typically poor.


Coincidence: This is, in typical floor/ceiling and wall assemblies, a higher frequency resonance. While very dramatic - it may slice 30dB off the performance of some wall types - it's not generally as important as the low-frequency mass-spring resonance.


Other resonances:

resonances in drywall panels higher in frequency than the mass-spring resonance: All practical walls will exhibit resonances in the panels at frequencies ranging from subwoofer to midrange. The exact nature of these behaviors varies from wall to wall. For the most part, these resonances occur between "stiffness points", between constraints on the panels. For example, drywall partitioned by resilient channel or studs in a double stud wall behaves as a mini-panel, and so on and so forth. These are milder problems than mass-spring resonance as well most of the time, but in many wall types are more important than coindidence.

unbonded layers resonance: the NRC in Canada outlined in it's documen tIR-811 that an apparent tiny air space between un-bonded layers of drywall causes a resonance that reduces mid-band performance by a reasonable amount. In some of the cases, they measured lower performance with 2 layers of drywall on each side in some frequency bands than with just 1 layer. This air cavity is the cause.


And so on and so forth. Walls are pretty resonant little buggers.



The attached pic shows the resonances in a couple of different walls - a deep steel stud wall, a resilient channel wall, and a 2x4 wall.

These resonances exist in all walls, but at different frequencies and severities. The next post, i hope, will address how to handle them in different constructions.

Brian

Glad to know us Canadians are doing our part ;) Brian I have a question, a little overwhelmed going through all your posts so bare with me.

My HT is constructed with the styrofoam blocks (I used integraspec). With your explanations you noted about mass and air space.
- Due to the fact my wall is essentially built with concrete would this improve, impede, or not do anything for my sound in my ht?
- The styrofoam itself is not a solid mass could this cause problems with absorption?
- Should I go to the extent of 5/8 1/2 GG drywall?

If I am repeating something you missed sorry, but you have supplied a lot of information and I find myself going through it a couple times already.

Pitbully:

Due to the fact my wall is essentially built with concrete would this improve, impede, or not do anything for my sound in my ht?
The concrete and styrofoam will not absorb anything from an in-the-room-acoustics point of view. It's not a room treatment.
The concrete will lower the noise floor in the room from that path, because it is mass. The stryofoam might damp the concrete a bit, but I doubt it.
The styrofoam will not act as absorbtion in the spring part of mass-spring-mass, so it won't contribute to the TL of the wall.
Stryofoam is a heat insulator.

http://www.integraspec.com/frame.html says "STC (Sound Transmission Class) = 50+ minimum "

I wonder how much all that steel from one side to the other would affect the TL.
Probably not much.

Should I go to the extent of 5/8 1/2 GG drywall?If you have soundproofing goals, then drywall/GG/drywall is a good idea.

Any chance you could update your profile with a location (city/province/country).

Sure Ottawa Ontario Canada

I knew the styrofoam was for insulation but also was using it instead of building walls. I just want to be re-assured that my whole theatre isnt going to sound like crap. I was worried with all the talk about insulating the walls and what not that I could not do that to improve the sound.


Now do I insulate the ceiling or put a suspended ceiling will be the next question :D

Glad to know us Canadians are doing our part ;) Brian I have a question, a little overwhelmed going through all your posts so bare with me.

My HT is constructed with the styrofoam blocks (I used integraspec). With your explanations you noted about mass and air space.
- Due to the fact my wall is essentially built with concrete would this improve, impede, or not do anything for my sound in my ht?
- The styrofoam itself is not a solid mass could this cause problems with absorption?
- Should I go to the extent of 5/8 1/2 GG drywall?

If I am repeating something you missed sorry, but you have supplied a lot of information and I find myself going through it a couple times already.

the styrofoam isn't good for much of anything, room acoustics or sound isolation, but as BB said, the concrete is good. it's very, very heavy.

adding GG and drywall + an air space will help isolation, but if room acoustics are your concern, i would turn my attention to bass traps and things before Green Glue.

putting some fiberglass in a corner will help sound in the room, using GG will help keep sound out of the room, or from leaving the room.

hey folks, if i could ask a favor.

It seems to me that so many people could avoid so much confusion, and more easily build better walls if i could nicely communicate these 5 basic principles of sound isolation. Think of the thousands of hours of wasted time making bad plans that people could avoid. But it seems to me that i'm not quite a poet, so to speak, that what i jot down in these posts isn't always concise or clear enough.

I've thought this over for what seems like a good long while, see if this makes more sense than my longer-winded jabber


There are 5 basic principles to sound isolation.

The first is mass. Sound is transmitted when airborne noise vibrates a wall, and mass offers resistance to vibration. It's harder for sound to vibrate a heavier wall.


The second is decoupling. Decoupling means breaking the mechanical path between two sides of a wall. Decoupling is frequency dependent, and all decoupling schemes will falter somewhere at low frequencies. To maximize the frequency range over which decoupling is effective, abide by these rules

1. use as much mass on both sides of the wall as possible
2. use as deep of an air cavity as you can spare
3. use insulation in the cavity. fiberglass is as good as anything, and it's cheap
4. for best results, don't use resilient channel
5. never build a wall with more than one air cavity, this is called a triple leaf wall.


The third is absorption. Putting absorption in an air cavity helps stop sound passing through the air cavity, but can't help with sound traveling via mechanical paths, like through studs. Another thing absorbing materials help with is lowering the frequency to which decoupling is effective. There is no reason to believe that overall (including low frequency performance) performance of any type of insulation or absorbing material is better than cheap, plain, fluffy fiberglass when used in walls. In general, the biggest gain from insulation is going from zero to some, and the gains for using progressively more and more are incremental.


The fourth is resonance. Resonance is like "anti-mass". mass makes it harder for sound to vibrate a wall, resonance makes it much much easier for sound to vibrate a wall. Essentially every stud wall has it's overall performance limited by low frequency resonance.


The fifth is conduction. Conduction refers to a structure or materials ability to transfer vibration along mechanical paths. For example, the framework of a wall can carry vibration up to a second-floor bedroom, or a concret slab can carry sound over to the next room. This is called flanking noise. In walls with mechanical connections between the two sides, sound can transfer from one side to the other by traveling to the connection points.


The zero'th principle of sound isolation is obvious. Seals. If direct air paths exist from one room to another, all is lost. You must successfully seal your walls for them to perform.




These 5 principles + seals essentially define the whole of airborne sound isolation, and any discussion, however clever, not falling in line with them is likely folly. More detailed discussion is possible to infinity, of course.



Therefore, as these 5 principles + seals are in essence the whole of the situation, to improve the sound isolation of a partition you have to improve of of these princples.

To improve mass you might add another layer of drywall to each side. Tile over gypsum concrete is far heavier than 3/4" plywood. Etc. To understand which partition is better from a mass standpoint is easy. figure out how heavy it is.


To improve decoupling you can build a wall with RSIC clips instead of just screwing drywall onto the studs. You can build a double stud wall instead of a single stud wall, etc.


For absorption, you really can't make any huge improvements. For walls, use plain fiberglass that fills the cavity, or at least R11, depending on your budget. For ceilings, just use as much as you can afford/desire.


To improve resonance you can either lower the resonance frequency or damp the resonance. Lowering the resonance can only be done on decoupled walls, and to lower resonance follow the 5 rules i offered above. To damp mechanical resonances, you can use some type of viscoelastic damping system.


To reduce a systems ability to conduct sound, you have to either mechanciall damp it (with a viscoelastic material), or make the mechanical system non-continuous - like cutting a floor.


To distill it even more, perhaps it is reasonable to say that to improve sound isolation you can (assuming the wall is already sealed)

1. add mass
2. give a decoupled wall more air space (more air space isn't so valuable for coupled assemblies)
3. add insulation if there is none. adding more insulation isn't likely to make a huge difference.
4. raise the damping of the system
5. if a wall is currently not decoupled, you can add decoupling. When using decoupling, make sure to follow the rules above and consult a knowledgable person (or post here!) to ensure that your plan will offer good low frequency results. If a wall is curretly decoupled, you might be able to improve decoupling. For example, move from a resilient channel wall to a double stud wall.



and that's about it.


it's still long, i know, but it's alot shorter than my previous blabbings. :D

Hi everyone. I am seeking a little advice from people who know a lot more than I do about soundproofing...Please forgive me if my english is sometimes poor, french is my mother language...

I am currently building a dedicated home theater in my basement. My room is 20 ft. by 12 ft. with a 8 ft. ceiling height. Three of the walls are 8 inches thick concrete (foundation), with a two by four framing -24 inches OC- already built one inch away form the concrete. The fourth wall has been recently built with the double wall technique (two 2 by 4 walls -24 inches OC- one inch apart from each other). A double solid core door will be on that last wall. As for the ceiling, the wooden joists are 12 inches thick, 18 inches apart. A soffit had to be built running on both sides of the room (20 ft long) before drywalling to hide HVAC ducts etc...

Insulation is already in the walls and ceiling (roxul safe and sound 3 inches thick).

The ceiling and the double studded wall are the surfaces that need the most sound proofing, since the three other walls (and the floor) are the house's foundation.

I have already bought 20 sonopan boards (though I am not sure if I should use those) and 1/2 in. drywall.

Here are my questions...

1- Should I double-drywall the three walls with concrete behind them? I think this should help, but to what extent?

2- I plan on using the sonopan on the ceiling, directly attached to the studs, with two layers of gypsum under that, using 100% GG between the gypsum layers. Should I skip the sonopan? RSIC clips will probably make me lose too much height so I would like to avoid those...Ceiling is where I would need the most soundproofing.

3- As for the double studded wall, I plan on using two layers of gypsum on both sides. Would it be better to use GG 100% on only one side (and which side?) or use 50% GG on both sides? I also though of using sonopan plus drywall on the interior side, double drywall plus GG on the exterior side...is there any significant difference between those methods?

4. Finally, can I use GG on the sonopan? I don't think so since it is so friable (is that an english word?)


Thanks everyone for the great info I found on this thread. Green Glue really seems like a wonderful addition to any Home Theater! My budget is not unlimited, bit is quite "extensible" as long as a difference can be heard...(or not heard?)


Stephane Olivier

If you really want a sound-isolation door system, nothing beats communicating doors. Two doors to make an airlock.

By this do you mean 2 doors hung on the same jamb both swinging away from each other? If so, how much better would this be than just one solid core door? I will do the 2 door system only if it is substantially more effective. What about taking a hollow core door and filling it with sand? I know I am getting off the GG subject but I really do appreciate the input. This seems to be the best place to ask these questions because of your knowledge and prompt responses. Thanks again Brian.

gregavi:

By this do you mean 2 doors hung on the same jamb both swinging away from each other?Yes, a communicating door is 2 doors both swinging away from each other. Sometimes they are mounted on the same jamb, but larger airlock is better. On of the advantages of this is the seals don't have to be as good to get the same isolation, which makes them easier to open by children, and extremely good lasting performance for fewest dollars. The tradeoff is floor square footage devoted to a doorway, and of course the annoyance of walking through two doors. A variation on this is a room, perhaps with a pool table, that one walks through to get to the HT. The room becomes the airlock, with cheap exterior doors on both sides.
Communicating doors are much more effective than a single door, at least any single door worth less than $2000.
Communicating doors should be built simply with mass (solid core wood doors), and not be any 'soundproof door' that's made out of a fiberglass fill.

What about taking a hollow core door and filling it with sand?
Nope. Doesn't work.
Most hollow core doors are two weak structurally to take the weight of sand, they rip off their hinges, and explode out the bottom.
They're also often built with dividers so you can't actually fill them from the top.
If you're building your own door it is possible to fill it with sand, but it's easier to do it the BBC way (or if you're really into heavy doors on either side of an airlock, then the Paul Woodlock way).

www.bbc.co.uk/rd/pubs/reports/1994-14.pdf - door blanks
http://www.bbc.co.uk/rd/pubs/reports/1994-15.pdf - door seals
http://www.bobgolds.com/PaulsDoor/home.htm

So sand would work well, it's just that I would need a door that would support the weight of the sand. I could easily build a door “shell” that would support the sand. Is sand more or less effective than MDF? Should I conclude that the more effective one would be the one that is heavier? I’m thinking the MDF would be heavier than sand filled. I could be wrong. Paul Woodlock’s method does not include the use of GG between the MDF layers. I assume that using GG between layers would be even more effective.
Thanks for the responses.

Hi everyone. I am seeking a little advice from people who know a lot more than I do about soundproofing...Please forgive me if my english is sometimes poor, french is my mother language...

I am currently building a dedicated home theater in my basement. My room is 20 ft. by 12 ft. with a 8 ft. ceiling height. Three of the walls are 8 inches thick concrete (foundation), with a two by four framing -24 inches OC- already built one inch away form the concrete. The fourth wall has been recently built with the double wall technique (two 2 by 4 walls -24 inches OC- one inch apart from each other). A double solid core door will be on that last wall. As for the ceiling, the wooden joists are 12 inches thick, 18 inches apart. A soffit had to be built running on both sides of the room (20 ft long) before drywalling to hide HVAC ducts etc...

that's almost perfect choice of framing for by the concrete, and the other wall.

Insulation is already in the walls and ceiling (roxul safe and sound 3 inches thick).

The ceiling and the double studded wall are the surfaces that need the most sound proofing, since the three other walls (and the floor) are the house's foundation.

good choice of insulation, it's not overly dense. i always recommend fiberglass, plain old boring fiberglass, but i should ammend my post above, i will if i have time later in the eve.

I have already bought 20 sonopan boards (though I am not sure if I should use those) and 1/2 in. drywall.

Here are my questions...

1- Should I double-drywall the three walls with concrete behind them? I think this should help, but to what extent?

The effect of adding double drywall to those walls with concrete behind them on sound isolation will be to lower the resonance of the decoupled system. The added mass is meaningless considering that the concrete behind it would weigh, what? 20 times as much as the drywall.

But lowering that resonance is good. This is "flanking" noise - noise that would make it up the structure (either via the slab or up the framework holding the drywall) to somewhere else, and it's hard to predict what the flanking noise situation is like in any given real world situation. sucks.

2- I plan on using the sonopan on the ceiling, directly attached to the studs, with two layers of gypsum under that, using 100% GG between the gypsum layers. Should I skip the sonopan? RSIC clips will probably make me lose too much height so I would like to avoid those...Ceiling is where I would need the most soundproofing.

OK, the sonopan won't hurt anything, but i don't know how much it'll help, either. There is an RSIC system that goes alongside the joists for minimum height loss - it'd be 7/8" for the hat channel. Similar systems exist for spring ceiling hangers, i think.

What you describe will be a very good ceiling. It won't, however, perform to the standard of, say, a double-stud GG wall. In other words, a directly screwed GG ceiling is not as good as a double stud GG wall.



3- As for the double studded wall, I plan on using two layers of gypsum on both sides. Would it be better to use GG 100% on only one side (and which side?) or use 50% GG on both sides? I also though of using sonopan plus drywall on the interior side, double drywall plus GG on the exterior side...is there any significant difference between those methods?

50% on both sides.

Sonopan is lighter than drywall, i think, and i don't recommend it for the double stud wall. Mass is really your friend when building decuopled walls like double stud walls. If planning to use Green Glue, i firmly recommend all drywall and no soundboard.

If history proves me wrong, then corrected i will stand, but FWIW, the STC figures in sonopans brochure are all lower than walls tested at the same lab with all-drywall and same number of layers/configuration. Save the single-wood-stud walls for which i am not aware of a comparison.

4. Finally, can I use GG on the sonopan? I don't think so since it is so friable (is that an english word?)

friable is an awesome word, the first time i ever saw it used i had to run for a dictionary. you can, the porosity of the material makes it less good than with drywall (some of your goop gets squished into the board), but GG yields great damping with homasote+homasote.

The question becomes, in what situation would one want to use soundboard when drywall is far heavier?



Thanks everyone for the great info I found on this thread. Green Glue really seems like a wonderful addition to any Home Theater! My budget is not unlimited, bit is quite "extensible" as long as a difference can be heard...(or not heard?)


Stephane Olivier

it sounds like you planned your system very well. good luck.

By this do you mean 2 doors hung on the same jamb both swinging away from each other? If so, how much better would this be than just one solid core door? I will do the 2 door system only if it is substantially more effective. What about taking a hollow core door and filling it with sand? I know I am getting off the GG subject but I really do appreciate the input. This seems to be the best place to ask these questions because of your knowledge and prompt responses. Thanks again Brian.

Quiet a bit better, especially with non-perfect seal quality. If you build communicating doors with a little absorbing material in the cavity, you get some "leeway" with respect to seal quality. Seals are usually thel imiting factors for doors.

The question might become "do you, gregavi, need the quite a bit better". perhaps you could install one door, see if you are pleased, and then consider adding another?



if anyone is deeply curious, i can make a graph of what data i have for single-vs- communicating doors.

i don't mind non-GG subjects, ... except alternate products that aren't good, lol :eek: (humor), but the whole subject of sound isolation is pretty interesting to me, and it's nice to chat about.

So sand would work well, it's just that I would need a door that would support the weight of the sand. I could easily build a door “shell” that would support the sand. Is sand more or less effective than MDF?

Should I conclude that the more effective one would be the one that is heavier?

yes, yes. :)

a resonance called "coincidence" might also change, but i don't know what that behavior would be like for a sand filled door.


I’m thinking the MDF would be heavier than sand filled. I could be wrong. Paul Woodlock’s method does not include the use of GG between the MDF layers. I assume that using GG between layers would be even more effective.
Thanks for the responses.

What's the density of dry sand? lemme google it. looks like about 90-100 lbs/cubic foot. MDF would be about 45 pounds/cubic foot. So for a 1.5" thick door, the weights would be

all MDF: 5.8 lbs/square foot (pretty heavy)
with 1/2" of sand: 7.7 lbs/square foot (i assumed some of the volume in the sand layer was wood, as you'd need spacers/braces)

that's, based purely on mass, about a 2.5 dB improvement. Not really that big of a gain for the trouble. But not nothing, either.


GG should make a great addition for pretty low cost. 10-15 bucks worth of GG or some such thing.

Brian and gregavi:

The other (non mass) advantage of sand is that it sort of liquifies when shaken, reducing transmisibility and doing a bit of damping. Hit a 4'x8' sheet of MDF with a sledgehammer. Now with that same sledgehammer swing it down against the sand in a sandbox. Hear the difference.

There are two tricks with sand in a door (beyond the usual double strength jambs and multiple huge bearing hinges):
1) keeping it all the way to the top. So you have to be able to refill it after it's settled. Otherwise the sand will go around the sand, what a waste.
2) keeping the bottom from exploding. Unlike wood, there's a lot of expansion pressure at the bottom that's constantly trying to split the door.

There's a paragraph and a drawing in the "Master Handbook Of Acoustics" of sand in a door.

Personally, although initially intregued by the sand-in-the-door idea, I'm currently in favour of using (assuming DIY):
1) BBC style door plugs with GG between layers
2) fully decoupled communicating doors, using carpet to cover the decoupled slots around them
3) with rigid insulation in the cavity (the carpet is some absorbtion, but the rigid is more absorbtion), perhaps on the back of one of the doors if it's not an 'airlock' but more of a communicating door (less than 8" cavity).
4) no door handles. Use hydrolic closers
5) plenty of seals. Bank Vault multi level seals, while effective, are more tripping trouble than they're worth. Seals get attached to the door, not the frame, like your fridge -- that way shoes don't rip the seals off the jamb and grind the seals into bits.

Regarding doors, I think it is a a matter of degree and what's it worth. For my HT, everything I did worked out extremely well, going any further would have been overkill. For my doors (I have two, one on the side and one in the rear), I took a Safe 'n Sound and GG'ed a 1/4" layer of plywood to it. The door was hung with Stanley self-closing hinges. I have a push plate to open from the outside and a surface mounted pull plate to open from the inside. The door also has a layer of Linacoustics, covered by GoM. I used neoprene door sealers for the 3 contact edges and a automated door sealer for the bottoms (they close on an oak threshold which is GG'ed to Dricore).

This is not to say that going the extra mile isn't worth it in all cases, but for me this worked very well. For quite awhile I contemplated other approaches, but I obsessed on this project too much - the approach I used was relatively simple and (comparably) inexpensive. If I were to re-do the project, I'd do the same thing, except I'd use an auto door closer and get deeper hinges.

Brian and gregavi:

The other (non mass) advantage of sand is that it sort of liquifies when shaken, reducing transmisibility and doing a bit of damping. Hit a 4'x8' sheet of MDF with a sledgehammer. Now with that same sledgehammer swing it down against the sand in a sandbox. Hear the difference.



I get the jist of sand in stages, and i'm sure it's the best idea for that situation imagineable.

But for sound isolation purposes, for transmission loss in walls and doors and partitions of all sorts, ...

1) has anybody ever tested it?

2) http://www.avsforum.com/avs-vb/showthread.php?t=585813 for some thoughts on the damping properties of sand

3) from brn-232 of the NRC, field measurement of a parition with 2 2x4 walls spaced 3" apart and the center space filled with sand.:



"Sand is occasionally used in partitions in the belief that is has unusual acoustical properties. The wall in Fig. 32 must have been difficult to construct. The FSTC is quite high but had the internal plywood and sand been replaced with more glass fibre, and had extra layers of wallboard been applied on the enterior, the sound transmission losses would have been at least as good if not better.
>snip<
impact noise was transmitted through the sand in it. Cupboard doors being closed on one side of the wall were clearly audible on the other. "



Just some thoughts.

Regarding doors, I think it is a a matter of degree and what's it worth. For my HT, everything I did worked out extremely well, going any further would have been overkill. For my doors (I have two, one on the side and one in the rear), I took a Safe 'n Sound and GG'ed a 1/4" layer of plywood to it. The door was hung with Stanley self-closing hinges. I have a push plate to open from the outside and a surface mounted pull plate to open from the inside. The door also has a layer of Linacoustics, covered by GoM. I used neoprene door sealers for the 3 contact edges and a automated door sealer for the bottoms (they close on an oak threshold which is GG'ed to Dricore).

This is not to say that going the extra mile isn't worth it in all cases, but for me this worked very well. For quite awhile I contemplated other approaches, but I obsessed on this project too much - the approach I used was relatively simple and (comparably) inexpensive. If I were to re-do the project, I'd do the same thing, except I'd use an auto door closer and get deeper hinges.

This is a great post, bob, and an important point.

The most commonly asked question that i recieve is "what's better?" or "what's best?"

People ask "will RSIC clips make my wall better than just 2 layers of drywall with Green?"

or "is a room within a room really alot better?"


Those are great questions, logical questions. But often the best question would be "how much do i NEED to satisfy my situation". And that is borderline impossible to answer. Even with a full schematic of the house, there are still questions... many questions. How loud will you listen? How quiet do the next rooms need to be? I think a large percentage of walls/ceilings would give nice results with just a layer of GG and more drywall. large percentage. But some situations require more isolation than others, and being a guy answering questions... you don't really know what the details of the situation are.

What's best? build a floor floating on springs with 2 layers of OSB and 2" of gypsum concrete. On this floor, build an entire seperate set of studs with 3 layers of 5/8" and 2 layers of GG on all walls and ceilings. put 3 layers of 5/8" with GG on all other-side walls not made of concrete. put double OSB with GG and 2" of gypsum concrete then carpet on the floor above. Use 2 doors, one on the outside room, one on the inside room, with no connections - step over an air gap...

lol

but does anybody need that much isolation? One gent built a room within a room with TEN layers of drywall/gg. how that passed city code i can't begin to imagine, but whatever.

do you need that much? almost certainly not.

does anybody need communicating doors? boy, i don't know, i do know they are the best answer.


The gent that basementbob referenced above, i believe, after a multi-year project that if he'd payed labor would have cost tens and tens and tens of thousands of dollars for the room, wound up opting to not finish sealing one door, as the isolation was good enough without it. I should double check to make sure that's true, but the irony is interesting.


The hardest question for me is "how much is enough"...

How about a mixture of GG and sand? Yummy!

What's best? build a floor floating on springs with 2 layers of OSB and 2" of gypsum concrete. .....

No, no, no. No springs! The inner room is magnetically suspended in a vacuum. :) The home theater on the space station will never be heard outside the station.

The home theater on the space station will never be heard outside the station.
So what I believe you're saying is that 'in space, no one can hear you scream', right :) .

Just a quick word to thank Brian for all his detailed answers, especially the one concerning my own set up...This thread is on of the most interesting I've been following so far!


Stephane Olivier

I would have one more question to ask Brian about my Home Theater setup. I will be using GG for the ceiling, sandwiched between two layers of gypsum. SInce the joists are 12 inches deep and the first layer of gypsum will be directly screwed under them, should I try to fill the cavity between the joists completely or just put 3 inches (or 6?) of Roxul Safe and Sound?


Thanks again for your help!


Stephane Olivier

don't assume that all VE materials are equal, they aren't, nor hardly, nor can a damping bench fully reveal what will happen at low frequencies in a real wall.

So who else exactly manufacturers VE materials? I know of AudioAlloy, QuietSolutions and who else?

Stef, use what insulation you can reasonably afford. There isn't reason to believe that using 10" of insulation will have a paramount gain relative to 6" for a non-decoupled ceiling. That's a GG ceiling, correct? You'd be better off to spend the money on a 3rd layer of drywall & split the GG into two layers. 6" is peachy.

You opted for no clips due to heigh restrictions?

Chil,

i know of no others, i googled for a second and didn't find anything, but i'm not the master of google. I would suspect that, sooner or later, the success of Green will draw similar products to market. Probably, someone will take an acoustic sealant and rename it. Probably, this won't work very well.

I beg the pardon of all if this sounds improperly immodest, but GG is the result of a many-hundreds-of-formulations R&D project, spanning fully 2 years from inception to finalization of the formulation now available in tubes. As a study that i hope will hit the Audio Alloy site the week of the 17th, or the week after, based on dozens of 3rd party tests will show, it brings resonance of the common 2x4 wall within ... the tiniest margin of critically damped mass potential. I do not think dramatic improvement is possible, and it would take blatant theft of the GG formulation (which itself wouldn't be so easy to do) or a herculean R&D effort to approach it. That study will also demonstrate a variety of other things that i'd wager nobody figgad would come to pass a couple years ago, self included.

Brian

I have a bit of a challenge, and I hope you guys would lend a hand.

I'm working on the basic outline of a basement theater right now. The entire west wall is towards the outside of the house and is poured concrete and 1/3rd of the screen wall is also poured concrete. The equipment room in the back of the theater is pretty much all poured concrete.

The rest of the perimeter is already studded with 5/8" gypsum drywall on the other side with exposed 2x4's facing into the theater space. 2/3rds of the screen wall is already studded and drywalled (it backs into a crawl space that is littered with load bearing support beams).

The usable unfinished space is approx. 21.5 x 13 (not including goofy angled walls, etc. that create dead space) with 93" from concrete floor to I-Beam ceiling joists, and I don't want to lose a heck of a lot of that space (so I don't think a double wall construction is in the picture).

I was thinking of layering the stud walls like this (before reading about GG): 5/8" gypsum with 2x4 framing (currently there), then R-19 insulation (backed??), a staggered 2x4 wall with 2x2 floor plate and header (leaving a 1/2" gap between current plates and the 2x2's), R-19 insulation, EDPM rubber matting used for pond lining attached to the new 2x4 frame, 5/8" gypsum, adhesive, staggered seam 1/2" gypsum. Seal all openings and perimeter seams with acoustic caulk (I'm not sure of what type yet). 1" furring, Insul-Shield, poly batting, and GOM on top of that.

I wasn't sure about the ceiling (maybe packing it with R-19 insulation, using the EDPM matting, and then 5/8" gypsum screwed to the I-Beams) or concrete portions of the wall.

Any suggestions? Again, I don't have a lot of space to play with to begin with, and was hoping to lose as little as possible while have really decent acoustics and sound transfer deadening... all without going too far over budget! :D

Thank you!!

Dan

I have a bit of a challenge, and I hope you guys would lend a hand.

I'm working on the basic outline of a basement theater right now. The entire west wall is towards the outside of the house and is poured concrete and 1/3rd of the screen wall is also poured concrete. The equipment room in the back of the theater is pretty much all poured concrete.

The rest of the perimeter is already studded with 5/8" gypsum drywall on the other side with exposed 2x4's facing into the theater space. 2/3rds of the screen wall is already studded and drywalled (it backs into a crawl space that is littered with load bearing support beams).

The usable unfinished space is approx. 21.5 x 13 (not including goofy angled walls, etc. that create dead space) with 93" from concrete floor to I-Beam ceiling joists, and I don't want to lose a heck of a lot of that space (so I don't think a double wall construction is in the picture).

ok, no double studs

I was thinking of layering the stud walls like this (before reading about GG): 5/8" gypsum with 2x4 framing (currently there), then R-19 insulation (backed??), a staggered 2x4 wall with 2x2 floor plate and header (leaving a 1/2" gap between current plates and the 2x2's), R-19 insulation, EDPM rubber matting used for pond lining attached to the new 2x4 frame, 5/8" gypsum, adhesive, staggered seam 1/2" gypsum. Seal all openings and perimeter seams with acoustic caulk (I'm not sure of what type yet). 1" furring, Insul-Shield, poly batting, and GOM on top of that.

I wasn't sure about the ceiling (maybe packing it with R-19 insulation, using the EDPM matting, and then 5/8" gypsum screwed to the I-Beams) or concrete portions of the wall.

That sounds pretty complicated. OK, faced or unfaced insulation doesn't matter much at all. Acoustic caulk is a must, of course, USG acoustic sealant is fine- it's waterborne, it's cheap, and as far as i konw it's the only lab-tested adhesive on the planet. That said, choice of sealant is'nt critical. it's getting a good seal that's critical.

Staggered studs are good. EPDM matting would be a substitute for limp-mass, like mass-loaded vinyl? It won't hurt anything, so if it's real cheap, feel free, but don't expect much. There is a reason that comparative same-lab data for limp-mass products doesn't seem to exist, despite dozens and dozens of sellers of such products.

For staggered studs, to improve performance look to mass (more layers of drywall) or damping (Green Glue or whatever else you can find). I think most historical staggered stud wall tests use double R9 insulation, rather than R19, the reason being that the stagg studs would compress the R19 so much in the "narrow part" of the cavity.

For the ceiling, you can use something like GG (again, don't look to limp mass to make a transformative change), or a decoupling product, like an RSIC clip. Those big air cavities inside the ceiling joists are a decoupling products dream, and you can attain very good results with a GOOD decoupling product and double drywall. Don't use resilient channel as it tends to be effective over a smaller frequency range, and has installation issues, relative to modernized decoupling products.

hope that helped & good luck :)

Brian





Any suggestions? Again, I don't have a lot of space to play with to begin with, and was hoping to lose as little as possible while have really decent acoustics and sound transfer deadening... all without going too far over budget! :D

Thank you!!

Dan

Hi. I live in Quebec, Canada.


I would like to order 48 tubes of the fantastic Green Glue. On the Audio Alloy site, I cannot order online since shipping and billing address must be in the States...What is the best alternative way for such an order...



Stephane Olivier

Call Ted at 989-832-1602

Thanks!

hey Stef,

i asked the web dude, and they are just re-arranging some stuff today & having some glitches.

B

All,

Has anyone who began their Green Glue room projects in mid 2004 finished them yet? It'd be great to have some post-project posts on here. I just finished the 4 or 5 hour long read of all 18 pages and some of you guys had pics of GG during installation... If you've finished, how do you like it?

I love my installation! Once you got over how sticky your hands were going to be (thing Ghostbusters slime in the library scene) things went well. I can't say scientifically if Green Glue solved all my problems since it wasn't as if I tested it with and without GG, but I can say I am happy with the results. I stated before that prior to carpet being installed and I had GG walls and cement floor, the room did not echo the same as the rest of the basement. Was it GG or possibly the room dimensions? Can't say for sure. I can play movies quite load without bothering people in other places in the house. The bass still gets through, but it is attunated significantly. I can play louder than I usually do and the family can have a conversation right above me in a normal voice.

As part of an upcoming book, I have been testing GG in the real world (all published results to date have been in labs). In my testing I have found that the STC ratings that are published are about 2 points on the high side.

On the positive side I have came up with good numbers for a typical installation of 3/8" over 1/2" that tracked just as good as 2 1/2"

Oops. One more thought. Hopefully someone can share the names of other manufacturers of viscoelastic glue (I am aware of QuietSolutions) so I can test them out over the next couple of weeks and post a final report here.

What is your testing methodology? In this industry we're not interested in STC, we're interested in TL.

chiltown:

that's interesting, by all means post your results. and please include your name, who ran the tests, what methodology was used and the like.

to get within 2 points of a lab test in the field for STC is really quite great, probably implies that flanking noise was very well controlled. it would be helpful to many to include the overall and entire construction details - how floor flanking was controlled, ductwork configurations, and so forth.

you sure must have ordered alot of Green to make a pair of field test walls (which must be an entire wall, i believe, per the applicable ASTM standard). As with all modern biz's, that stuff is all stored, clearly you wouldn't have just bought one case or something :)


and as Dennis said, a field STC test isn't really relevant.

have a good one

Brian

i know this forum is huge, seedlings,and i know lots of chat about Green is found here and there and everywhere, but there have been quite a few threads about this stuff.

i fear i hve no links or any such thing, but many comments about final results are to be found herein.

:)

As part of an upcoming book, I have been testing GG in the real world (all published results to date have been in labs). In my testing I have found that the STC ratings that are published are about 2 points on the high side.

On the positive side I have came up with good numbers for a typical installation of 3/8" over 1/2" that tracked just as good as 2 1/2"


http://www.avsforum.com/avs-vb/showthread.php?t=573989

these are the tests / book / request for free glue not granted?

:)

Hope to post full results of test including methodology over the next couple of weeks. Brian mentioned that there were other manufacturers of viscoelastic glue in which GG outperforms them. Awaiting for him to post manufacturers names so that I can acquire some and do a full report to the group.

NOTE: I already have QuietGlue but awaiting other sources

Hope to post full results of test including methodology over the next couple of weeks. Brian mentioned that there were other manufacturers of viscoelastic glue in which GG outperforms them. Awaiting for him to post manufacturers names so that I can acquire some and do a full report to the group.

NOTE: I already have QuietGlue but awaiting other sourcesUnless your results include an independent lab test that PROVES your free samples exactly match the product that is sold, I will consider your book pure fiction. Why do you think The Insurance Institute for Highway Safety buys each car it crash tests directly off a dealer lot? Asking a manufacturer for free samples to test shows a great deal of naivete.

--Dan

Why do you think The Insurance Institute for Highway Safety buys
Even at that, they don't test them under actual driving conditions.

Unless your results include an independent lab test that PROVES your free samples exactly match the product that is sold, I will consider your book pure fiction.
--Dan

For the record, GG never provided free samples. All the testing has been done based on paying for GG through multiple orders through multiple people.

Simply looking for the names of other manufacturers of Viscoelastic Glue so that they to can be included in the comparison testing...

If you were to do your own research ... for example, a google search on "constrained layer damping", I think you'd discover other resources and materials.

Brian mentioned that there were other manufacturers of viscoelastic glue in which GG outperforms them. Awaiting for him to post manufacturers names so that I can acquire some and do a full report to the group.



Simply looking for the names of other manufacturers of Viscoelastic Glue so that they to can be included in the comparison testing...




from earlier in this thread:

Chil,

i know of no others, i googled for a second and didn't find anything, but i'm not the master of google. I would suspect that, sooner or later, the success of Green will draw similar products to market.



you perhaps missed my earlier response?


:)

I don't usually respond to discussions like this but in this case I will.

I saw some of the earlier posts from chiltown and liked his idea about writing a book about building a HT. Such a book could be usefull for many people. But after having seen many of his posts here I doubt that he knows what he's talking about.

In any case I would rather trust information from reputable members such as Dennis and Brian, professionals in this field who freely share their knowledge to this forum, giving us novices a chance to build a great performing theatre that previously only could be found in commercial theatres or in luxury homes. Chiltown on the other hand is working for an insurance company! Whats his expertise? Good writer maybe? In any case he's probably getting all the info for his "book" from this forum and its knowledgeable members!


For the record, GG never provided free samples. All the testing has been done based on paying for GG through multiple orders through multiple people. ...

Why would anybody go through the pain of ordering through multiple people?

I also wonder if this is a plot to get free green glue! If not then this is a plot to discredit Green glue.

Brian - I'm also writing a book, can you please send me a truckload of green glue for free! I'll let you know how it performs later. :) STC right ;)

Cheers,

Exipnos

Chiltown on the other hand is working for an insurance company! Whats his expertise? Good writer maybe? In any case he's probably getting all the info for his "book" from this forum and its knowledgeable members!


Hmmm. I find it interesting that you have restated my approach as a problem vs. an opportunity. Would you suggest that a writer of a book on a subject not encompass bodies of knowledge such as the AVSForum?


Brian - I'm also writing a book, can you please send me a truckload of green glue for free! I'll let you know how it performs later. :) STC right ;)


If you were writing a book and knew anything about how to approach it, you would understand the economic decisions that need to be made. You would also understand that it has been traditional practice within the writing field for manufacturers of products to supply materials for free. Maybe you need to do homework before "assuming".

Maybe you might not have known that other manufacturers did supply stuff for free and that GG was the only one that didn't. If you believe that stating the facts are an attempt to discredit then so be it. I was simply sharing the process of how books are created and what I have learned along the way...

There are writers that do not want the materials they are writing about for free. That may place a bias that shouldn't be there just because one company was "easier" to work with. I think Consumer Reports purchases everything they test themselves, without knowledge of the vendors.

I just don't get the mentality here of cutting these corners. Green Glue is not that expensive considering the cost of the overall construction. The choice of this material cannot be changed once the walls are up.

So why screw around with untested alternatives?

Buy cheaper speakers, or a DVD player, or even a cheaper projector that will be obsolete in twop years anyway. These can be easilty upgraded later. But you really can't go back and replace the acoustic filler after the fact if your substitute product doesn't work as expected.

"Penny wise, Pound foolish" comes to mind.

There are writers that do not want the materials they are writing about for free. That may place a bias that shouldn't be there just because one company was "easier" to work with.

I agree and disagree. A writer shouldn't be biased about ease of working with a company when obtaining free materials. He does though have a fiduciary duty to share his/her experiences in the process.


I think Consumer Reports purchases everything they test themselves, without knowledge of the vendors.

Consumer reports pays for all materials themselves which is the manner I used. Essentially there are two models. Model one says that if a writer gets materials for free then he may have the opportunity to share results for free. The second the writer takes on expense, it simply needs to be covered which results in folks having to pay for unbiased information.

Writers really have no preference as to whether consumers get access to the information they need and is 100% determined upstream...

I just don't get the mentality here of cutting these corners. Green Glue is not that expensive considering the cost of the overall construction.

"Penny wise, Pound foolish" comes to mind.

It is important to be respectful of others ability to afford or not afford things. Maybe he is one of the few that excercises fiscal responsibilty when it comes to sticking to a budget. Maybe we should follow his model.

I do agree that GG is not expensive relative to the overall cost of construction but if one cannot afford it then the relative cost really doesn't matter.

I want to write a book about building sports cars. I am really interested in the suspension systems. Now I know these cars seem to be popular in some circles but are rather pricey. It seems that some can't afford what people say is a good one, but I understand that I should be able to find an affordable alternative. And lets face it, you can put in different engines all of the time but if you don't have the suspension, then you don't have handling.

I realize there are various organizations that test the vehicle parameters and tabulate the results with respect to handling. You know lateral G forces, maneuverability, skid pad, whatever. But I want to know what the common man can expect from building their own. You know, just like all of the racing teams do.

Now then, I specialize in underwater basket weaving, which like many endeavors is all about details, so this should not be a big stretch. I have a buddy that can spell accelerometer and he has a volt meter. I can use my kids go-cart track for some of the testing.

Unfortunately, I don't know who makes the darn things. You know, the suspension systems. Could some of you knowledgeable members tell me please? I am sure that if you teach me what I need to know to write the book that I will have a blast and maybe even make some money. Not quite like Paper Lion , but you get the idea.

You all seem like quite a nice bunch and appear to share your knowledge freely to help each other. Since you seem to be involved in what some may consider as pricey endeavors, I figure you may have expeience in this other field.

So with my tongue firmly planted in cheek, toss a fella a bone, will ya? :)

It is important to be respectful of others ability to afford or not afford things. Maybe he is one of the few that excercises fiscal responsibilty when it comes to sticking to a budget. Maybe we should follow his model.

I do agree that GG is not expensive relative to the overall cost of construction but if one cannot afford it then the relative cost really doesn't matter.

My point is to cut the budget somewhere else. Buy cheaper chairs or something that can be upgraded later.

Jamin,

You have put your post in the wrong forum. Please go to the "fast sports cars" forum. I'm sure they can help you find a suspension that costs half as much and works just as well. And watch where that tongue is going, too.

I just spent the last 2 evenings reading all 19 pages and would like to say "impressive data." I am a simple county guy from out in the sticks so I got lost with the sound ratings and e=mc2 stuff in some of the posts, but, I can say that after all this reading I have switched from DIY single layer sheet rock to the 5/8 SR //GG// 1/2 SR method that seems to be the over all most efficient for the money (which I have VERY little of for this project) I also have decided to bring in a contractor that knows something about this if I can find someone in my budget. My biggest thanks though goes to Glimmie, my wife could see absolutely no reason to spend the extra money on Glue and understood the technical reasons for it even less than I did. When I explained that I could take money out of equipment or furnishing that we could get by with at mediocre for a while then upgrade later but that we couldn't redo an entire wall system I finally sold the idea and earned a little better budget for some "crazy kind of green stuff" her words not mine. Thanks to all of you for making me just a little closer to my dream.. I have a call in to order some of the stuff by phone (don't trust this internet ordering stuff much) and have not got a call back yet. In fairness though its late and I only called about 10 minutes ago. Thanks also for being professional in all your comments. The profesionalism and people skills of the posters associated with Audio Alloy sold me the product more than the specs. People I understand... Tech talkin I just have to accept.

Jamin,

You have put your post in the wrong forum. Please go to the "fast sports cars" forum. I'm sure they can help you find a suspension that costs half as much and works just as well. And watch where that tongue is going, too.
Thank you for your help. Turns out that by reading the many years of posts in the archive section I found out that these latest suspension systems are in fact what people have been looking for for a long time and that the $_to_performance ratio is right on. Seems as if the other methods are well documented as to the performance and cost so I will just suck it up and buy cheaper headlights and seats in the mean time. Hmm, now there is a story there too maybe :)

jamin

I heard that peanut butter in the suspension makes it work better.....

Aha kras, that must be the new viscous fluid in those fancy shocks - folks say they will get you around the track in a jif.

I just spent the last 2 evenings reading all 19 pages and would like to say "impressive data." I am a simple county guy from out in the sticks so I got lost with the sound ratings and e=mc2 stuff in some of the posts, but, I can say that after all this reading I have switched from DIY single layer sheet rock to the 5/8 SR //GG// 1/2 SR method that seems to be the over all most efficient for the money (which I have VERY little of for this project) I also have decided to bring in a contractor that knows something about this if I can find someone in my budget. My biggest thanks though goes to Glimmie, my wife could see absolutely no reason to spend the extra money on Glue and understood the technical reasons for it even less than I did. When I explained that I could take money out of equipment or furnishing that we could get by with at mediocre for a while then upgrade later but that we couldn't redo an entire wall system I finally sold the idea and earned a little better budget for some "crazy kind of green stuff" her words not mine. Thanks to all of you for making me just a little closer to my dream.. I have a call in to order some of the stuff by phone (don't trust this internet ordering stuff much) and have not got a call back yet. In fairness though its late and I only called about 10 minutes ago. Thanks also for being professional in all your comments. The profesionalism and people skills of the posters associated with Audio Alloy sold me the product more than the specs. People I understand... Tech talkin I just have to accept.

hey XTC,

thanks very much for the kind words.

you mentioned that cost was an issue. It really is only a slight compromise to use 1/2 the recommended amount of Green Glue if you follow the pattern suggested in the directions.

let me see if i can find a link to those... here: http://www.audioalloy.com/b11-00_application.html

good luck, and don't hesitate to post or email,

Brian

on a side note, but related to recent discussion in this thread, i believe that AVS owns the content of it's site, and would therefore have the right to allow or disallow copying of this site into books or articles or whatever.

If a mod ever reads this thread, perhaps they could comment. But i think it's Alan/Dave/etc.'s information.

Brian:

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Bob

The way I understand it is that by posting on AVS you do not give up copyright - you just give some rights to AVS Forum, Inc. - but not to AVS members. AVS is more restricted with media than texts based on what the originally poster made it available for. So nobody can copy anyones posts anywhere else, except the original poster. Better just to link to the AVS post if you are elsewhere - and paraphrase. Good policy for AVS - if the content is here - make them come here.

I would think Audio Alloy would want to copyright at least some of Brians ramblings and chartings lest someone less ethical than they use that to sell other products that they have nothing to do with!

I'm not a lawyer I just take their advice! Which is why KRAS Muzik, LLC posts are copyrighted

thanks bob, kraz, good thinking & done.

on a side note, i didn't mean "plagarism" to imply anybody was engaged in misconduct or actions of a questionable nature. i'll go edit my post.

Brian

I think you need to put the year for a legit copyright - but then if the posting is already dated - not sure

you can only have 150 characters in your signature. And i don't mind at all if anybody copies or reproduces anything i post for non-commercial purposes as long as it's reproduced in context (as in nobody cherry picked what i typed to skew its intent), and i guess i would give permission for somebody copying it to sell as long as they stated the source and, again, didn't skew the context.

i guess my concern would be that the work i put into posting not go towards dis-helping anybody, and as i think the content of what i post is solid, that means it has to be reproduced as it was intended.

but i ramble. 150 characters isn't that much. and i would, ideally, like to include the statement that data sourced from the NRC is copyright them and used with permission, but there isn't room for all of that stuff.

i'll think it over.

on a side note, but related to recent discussion in this thread, i believe that AVS owns the content of it's site, and would therefore have the right to allow or disallow copying of this site into books or articles or whatever.


Imagine a situation in which home theater builder wanted to cite hundreds of examples of success by real world customers of GG but weren't allowed to do so because of the restriction you posted...

The entire community including AV Science, GG and its readers may be well served in erasing the notion of copyright and instead adopting something similar to: http://www.gnu.org/copyleft/copyleft.html

The entire community including AV Science, GG and its readers may be well served in erasing the notion of copyright and instead adopting something similar to: http://www.gnu.org/copyleft/copyleft.html
No way. With copyleft, you are giving up all rights to your own intellectual property. I for one would stop posting here.

- Terry

chiltown

I suggest you put a copyleft on your book then.

Of course that means it would have to be free.....and GreenGlue could copy it and change all references to how great that FreeGlue stuff was so it now says GreenGlue is great - then give away your modified book for free.

chiltown

I suggest you put a copyleft on your book then.

Of course that means it would have to be free.....and GreenGlue could copy it and change all references to how great that FreeGlue stuff was so it now says GreenGlue is great - then give away your modified book for free.

CopyLeft doesn't mean that GG couldn't sell it for money. They are also welcome to purchase copies and give them away freely. They are free to do whatever suits their needs. It also doesn't prevent them from modifying it or enhancing it.

FYI. One book in which I was a lead on: XQuery was licensed under this model...

No way. With copyleft, you are giving up all rights to your own intellectual property. I for one would stop posting here.

- Terry

CopyLeft doesn't state that you lose all of your IP. It also doesn't state that attribution of ideas disappears. The biggest benefit to CopyLeft is that the community can grow without artificial constraints...

I may be in the minority here, but this thread seems to have deteriorated badly. I would love to see it get back on track on the subject of Green Glue and sound isolation principles and applications.

Any chance you guys could take the discussion of books, free products, and copyright laws to another thread?

Sorry... I'll go back to lurking now.

Maybe I missed something... this thread started with everyone using 5-gallon buckets of green glue and now their website only sells caulking tubes? Seems like the buckets would save a LOT of time. Are they still available?

Maybe I missed something... this thread started with everyone using 5-gallon buckets of green glue and now their website only sells caulking tubes? Seems like the buckets would save a LOT of time. Are they still available?
When it was only offered in buckets, there were a lot of people asking for tubes. I would guess that it is more cost effective for Audio Alloy to produce and stock it in only one packaging type.

I've used it in both versions. While it might seem that the buckets would be faster, I don't think it is all that different. The stuff is SOOOOO sticky, it gets on everything. When you use it directly out of the buckets, you can't help but get it all over, no matter how careful you are. I ended up spending an awfully lot of time just trying to keep it cleaned up. For me, it took about an extra 10 to 15 minutes per sheet to spread the Green Glue from the bucket with a trowel.

I think the tubes can be easier and cleaner to use, especially if you are applying the green glue to small areas like the face of your studs. The big disadvantage to the tubes, IMO, is that if you have very much of it to apply, your hands and forearms can get awfully tired and sore from squeezing the trigger on the caulking gun. The other disadvantage to the tubes is that if a tube gets damaged, especially if the plunger on the butt end of the tube gets bent, it can turn into a huge mess.

I'm not finished with my project, and I still have a lot of drywall to hang, but so far I think I prefer the tubes over the buckets. Either way, you have to plan on it taking extra time and you have to plan on a bit of a sticky mess.

(By the way, get a big bottle of Avon skin-so-soft bath oil. It is GREAT for taking the sticky Green-Glue residue off of your hands and tools. It won't clean up big globs of the stuff, but it will take off the left-over sticky film.)

I may be in the minority here, but this thread seems to have deteriorated badly. I would love to see it get back on track on the subject of Green Glue and sound isolation principles and applications.

Any chance you guys could take the discussion of books, free products, and copyright laws to another thread?

Sorry... I'll go back to lurking now.

sounds very reasonable indeed. :)

Maybe I missed something... this thread started with everyone using 5-gallon buckets of green glue and now their website only sells caulking tubes? Seems like the buckets would save a LOT of time. Are they still available?

we haven't sold pails, except to specialty applications such as manufacturing in some time.

If there is a reason that you'd prefer the pails, just post your thoughts & it should be possible to send some.

But that said, in general the tubes are much neater, and perform less or more the same (if anything a touch better in real world situations). they are a little more expensive than the pails.

is AVS special pricing or a powerbuy still ongoing?

yes, there is an AVS price, just mention when ordering.

I just got done using 6 cases of tubes. I thought it was very easy. The tubes also make it easier to keep track of how much you are using. Just use 2 tubes per sheet and you know you will not be wasting it or using too little.

I do have a question though. What is the best way to clean this off of tools and hands, besides the Avon oil stated above ? I know the instructions say to use shampoo, but for me that did not help much. This stuff is really sticky.

Why don't you want to use the Avon bath oil? It really does work great. Ask your wife or girlfriend if she knows an AvonLady, or you can get it online here. (http://shop.avon.com/avonshop/product.asp?pf_id=7613&from=search&find_spec=skin-so-soft )

Thanks Scott. I just figured it would be hard to find the Avon stuff. There must be other alternatives to clean this sticky stuff up.

Brian are you there ? Any good ideas on what to use to clean up Green Glue ?

Thanks Scott. I just figured it would be hard to find the Avon stuff. There must be other alternatives to clean this sticky stuff up.

Brian are you there ? Any good ideas on what to use to clean up Green Glue ?

Hi N4u,

good morning.

at the lab we use rubbing alcohol, shampoo & acetone. Obviously acetone isn't for skin.

i don't have all that much experience with cleaning it off common power tools, but you could try baby powder (to ball it up) + something to scrub it off. My understanding is that the Avon product is the best stuff around.

For cleaning it off the skin, just shampoo and perhaps a little scrubbing with a wash cloth has always done the trick for me. :confused:

baby powder to relieve it of it's tack can go a long way in some situations.

Brian

Thanks for the reply Brian. I will have to try to get a hold of some of that Avon product. I am basically done installing my drywall, but I have a lot of tools with the green Glue still on them. Just trying to figure out how to clean up or dissolve the glue oh the tools.

Brian Ravnass, Brian Dayton, Ted White, etc...
Basically, any and all Audio Alloy reps:

Where do I find independent hard numbers on STC / OITC / MTC figures for Green Glue?

I've been scanning several forums containing Green Glue threads (as well as a couple I've started over the past several weeks), and after all the testimony, rhetoric, and opinion, I can't seem to find any independent test data.

Thanks.

Brian Ravnass, Brian Dayton, Ted White, etc...
Basically, any and all Audio Alloy reps:

Where do I find independent hard numbers on STC / OITC / MTC figures for Green Glue?

I've been scanning several forums containing Green Glue threads (as well as a couple I've started over the past several weeks), and after all the testimony, rhetoric, and opinion, I can't seem to find any independent test data.

Thanks.

you might try the "email" button under one of my posts, or perhaps post a request for what data you would desire to see (what wall type, etc.)

such data is entered above in this thread, although i think the pictures of graphs (and regrettably most of the pictures i've entered here) are lost in the shuffle of a web site change.

GG is one of the most tested products in existence, and will probably soon be the most tested. It takes some time to get reports from the labs, and to get them loaded onto the site, but you and anybody else is welcome to write & ask for them. :)

Brian

What is your opinion on 5/16" Ecofoam, impact noise reduction material in 6x9 ft roll for 0.73$CAN / SQ ft for full coverage in drywall sandwich? Uniform coverage in peaces or intentionally leaving 20% of the area uncovered results in half GG price. For 50% coverage results in 1/3 GG price. What would be negative side?
Thank you

There is a constant theme here. The folks who make GG always compare themselves to other overpriced expensive methods for sound reduction while us consumers are always comparing GG to the cheapest thing possible.

In the long run, consumers always win causing the price of GG to drop. In the short term, GG is the cheapest game in town, albeit it is still expensive...

What is your opinion on 5/16" Ecofoam, impact noise reduction material in 6x9 ft roll for 0.73$CAN / SQ ft for full coverage in drywall sandwich? Uniform coverage in peaces or intentionally leaving 20% of the area uncovered results in half GG price. For 50% coverage results in 1/3 GG price. What would be negative side?
Thank you
The negative side is that it won't work. ;) At least not for airborne sound isolation. Impact noise is a different animal. It is tapping (such as a footfall sound) typically conducted through a floor.

- Terry

There is a constant theme here. The folks who make GG always compare themselves to other overpriced expensive methods for sound reduction while us consumers are always comparing GG to the cheapest thing possible.


a small % doesn't constitute always, chiltown. and compared to just adding drywall isn't less favorable to GG than other comparisons.

but in any case, my good fellow, i think alot of it stems from people not fully understanding what GG does. GG isn't an air layer, it isn't a "decoupler" or a "cushion" or any of those, it's a damping material. compared to any other possible engineered damping material, i think you'll find it the cheapest of the lot (and i encourage you to test this). and it's only natural for people to wonder if damping properties could occur/would occur/do occur in something at a Menards near them.

The downside to DIY damping solutions is that you risk a backfire, as the wrong material between drywall layers is a negative from a sound isolation standpoint. See any of probably 100's of posts here and there on the web not recommended rigid adhesives, etc., and so on. So it's not a good idea to start trying things.

there are alternatives to RSIC clips or Green Glue... staggered and double studs come to mind. I posted on the relative virtues of GG single studs -vs- double studs the other day. With all things there are tradeoffs - those would require more insulation/labor/space, i suppose. TINSTAAFL - it's as true in most of life as it is in economics.

If you want to use a DIY damping solution and the thoughts above won't dissuade you, utilize the softest, thickest asphalt sheet that you can find. i.e. roofing rubber and avoid anything else. do not use asphalt coatings, they will backfire. thickest roofing felt sheet you can find, NOT common tar paper.

Sound reduction solution includes methods and materials. Basic analysis & test should take care of this and provide comparable baseline ("decouple" method value from material value). Specifically, you can follow valuable method (5 Points of Isolation: Mass, Mechanical de-coupling, or mechanical isolation, Absorption, Resonance, Conduction) with other 10 or 20 times cheaper viscoelastic materials and make tangible conclusion on GG value. Otherwise, comparing different methods without using (logically) comparable materials within same method, you, methodologically, do not "walk the talk": you are not de-coupling!

"Green Glue retains ~2/3 to 3/4 of it’s full-coverage performance when utilized at 50% coverage, which is important for sound isolation applications on a budget. It may well be possible to utilize even lower coverage and get performance well exceeding that of other damping options."

Does it means that material is not critical as long as you follow method?

What would be result if you use 10 or 20 times cheaper (any permanently elastic) glue/material, with 100% coverage? Why there is no Independent Laboratory Test Report that includes 5 Points of Isolation?

Sound reduction solution includes methods and materials. Basic analysis & test should take care of this and provide comparable baseline ("decouple" method value from material value). Specifically, you can follow valuable method (5 Points of Isolation: Mass, Mechanical de-coupling, or mechanical isolation, Absorption, Resonance, Conduction) with other 10 or 20 times cheaper viscoelastic materials and make tangible conclusion on GG value. Otherwise, comparing different methods without using (logically) comparable materials within same method, you, methodologically, do not "walk the talk": you are not de-coupling!

"Green Glue retains ~2/3 to 3/4 of it’s full-coverage performance when utilized at 50% coverage, which is important for sound isolation applications on a budget. It may well be possible to utilize even lower coverage and get performance well exceeding that of other damping options."

Does it means that material is not critical as long as you follow method?

What would be result if you use 10 or 20 times cheaper (any permanently elastic) glue/material, with 100% coverage? Why there is no Independent Laboratory Test Report that includes 5 Points of Isolation?

srba,

i do apologize, but i don't think i follow your post. every independent lab test ever run - more than less - includes the 5 points of isolation.

mass = mass law = established in hundreds of tests over the years
decoupling = RC, sound clips, staggered and double studs = established in hundreds of tests over the years
absorption = insulation = established in hundreds of tests over the years
resonance = 100's of tests

and so on. Those are the principles, and functional products affect one or more of them. for example, just adding drywall improves sound isolation (adding mass). using RSIC clips improves isolation (decoupling), using GG improves isolation (resonance and conduction), using insulation improves isolation (absorption), and so on and so on.

you can use less GG than the full recommended dose and retain most of GG's performance. And again i apologize, but i'm to bleary this morning, i fear, to see how the statement you quoted above relates to other materials, and there isn't any material 20x cheaper than GG of any kind AFAIK

thanks,

b

I just need to know whether anybody ever used any permanently elastic glue/material (there are such materials more then 30 years on the market) while following same basic isolation method (sandwich,.. etc. like described in 5 Points of Isolation)?
Thank you

I just need to know whether anybody ever used any permanently elastic glue/material (there are such materials more then 30 years on the market) while following same basic isolation method (sandwich,.. etc. like described in 5 Points of Isolation)?
Thank you

yes, i understand! :) something such as silicone sealant, which is permanently elastic, perhaps?

silicone is ~1/2 the cost of Green Glue (or more for higher end brands), FWIW.

most permanently elastic materials such as silicone, neoprene, simple latex rubber (elastic until oxygen degradation renders it crumbly), EPDM, or various other forms of thermoplastic material tend to be extremely low in damping. typically the materials themselves are 5% or less of critical damping, which means they can't contribute much to the dmaping of a wall.

butyl rubber, or butyl rubber blends such as butyl rubber + butene polymers as a plasticizer - are the best damping of ancient materials. butyl rubber has ~20% of critical damping.

but GG can impart ~30% of damping to two layers of drywall in a sandwich configuration, and per the calculations in ASTM E756 that correlates to ~300% of critical damping for the behavior of the material itself. I don't know how accurate that is, i don';t think the equations were meant to be relevant when damping gets that high.

So, when it was stated that using less GG to lower costs can still outperform basically all other damping amterials, that's where we're coming from. butyl rubber based sealants won't be inexpensive, and they also won't be designed for damping, but for sealing, and as such much of the somewhat limited potnetial will likely be lost.

Therefore materials such as these fail to contribute to any of the 5 points of isolation, as a thin layer between materials can't effectively decouple, and they don't substantially contribute to damping. and they aren't mass or insulation, so they don't fall under any of the 5 points.

if a materials properties are not appropriate, and you put it between drywall layers, then sound isolation can be worse than if one used nothing between drywall layers.

So, i would offer that i don't think the use of untested materials between layers of drywall is a good idea.

If you want to not use GG or sound clips, that's fine, and it's still 100% possible to get good isolatoin, just use staggered stud walls or double stud walls and the like. For theater even if installed, and for the fact that installation problems are the norm, i don't generally recommend resilient channel.

good luck!

Brian

PS: the attached graph shows the behavior of an efficient viscoelastic material on damping compared to the behvaior of an elastic material on damping. elastic materials return energy efficiently and don't raise damping much.

Ok so after reading 20 (twenty) pages of green glue stuff, here is what I am tentatively planning on doing. (After I get my design, my permits, my drywall, my WAF and my NERVE!!)

1) Vapor barrier on concrete, then build a wall in front of the two concrete walls with 2x4's. (1 inch away?)
2) insulation, GG on joists on ceiling, then 5/8" drywall, GG, and then 1/2" drywall
2) some kind of insulation on concrete walls, then GG on studs, 5/8" drywall, GG, then 1/2" drywall.
4) Same on the other two non-concrete walls

Does this sound like what I need? Am I on the right track?

I hope my 2 days of reading were not in vain!
Chinaclipper

Ok so after reading 20 (twenty) pages of green glue stuff, here is what I am tentatively planning on doing. (After I get my design, my permits, my drywall, my WAF and my NERVE!!)

1) Vapor barrier on concrete, then build a wall in front of the two concrete walls with 2x4's. (1 inch away?)
2) insulation, GG on joists on ceiling, then 5/8" drywall, GG, and then 1/2" drywall
2) some kind of insulation on concrete walls, then GG on studs, 5/8" drywall, GG, then 1/2" drywall.
4) Same on the other two non-concrete walls

Does this sound like what I need? Am I on the right track?

I hope my 2 days of reading were not in vain!
Chinaclipper

hey clipper,

man, 20 pages. well, since 20 pages it is, perhaps a little summary of some points that aren't covered that thoroughly herein is in order

A COUPLE OF SIMPLE TIPS FOR WALLS WITH OR WITHOUT GREEN GLUE

-the use of furring strips in the form of 1x4 or 1x3 wood strips, or metal hat channel, perpendicular to the studs/joists and spaced 24" on center can nicely improve performance for almost no cost. in combination with Green Glue or other forms of damping, this is particularily effective. in combination with standard drywall (no damping), this is still effective, but not as much so. still, it's worth the very low cost for any application that isn't going to utilize staggered or double studs, or sound clips like RSIC or ISOMAX

-the use of 24" on-center studs will help basically all types of walls perform a little better. for all walls, 24" OC is a little better than 16" OC. no need or desire for furring fi you use 24" OC studs (it doesn't hurt, but doesn't help as much). if you're studs are 16" OC, don't panic, if they are closer together than 16" OC, use RSIC clips (instead of or in combo) or furring (in combo with) Green Glue.

-it's preferable on all wall types to utilize 3 layers of drywall and 2 layers of green @ 50% coverage relative to 2 drywall / 1 GG @ 100% coverage. (heavier = a good thing, same cost of GG = a good thing)





ok, onto your post.


1) Vapor barrier on concrete, then build a wall in front of the two concrete walls with 2x4's. (1 inch away?)
2) insulation, GG on joists on ceiling, then 5/8" drywall, GG, and then 1/2" drywall
3) some kind of insulation on concrete walls, then GG on studs, 5/8" drywall, GG, then 1/2" drywall.
4) Same on the other two non-concrete walls


1) is the ideal situation for concrete. concrete / space / studs/drywall.
2. i recommend using furring as mentioned above, so little cost, nice gains
3) perfect, no need for exotic insulation
4) perfect, still no need for exotic insulation, but you could improve things should you deem it necessary, by utilizing staggered stud or double stud walls (a little more space, a little more cost)

also, make sure to mind the details like seal quality, potential noise paths through ductwork, and use a wealls ealed, heavy door (like exterior steel or solid core wood, with improved seals from the factory seals).

good luck & post whatever questions you might have,

Brian

Brian -
You mention this often ....

metal hat channel, perpendicular to the studs/joists and spaced 24" on center can nicely improve performance

I am planning to run my ceiling hat channel parallel to minimize loss of height (I expect to come it at about 7.5' or less after 2 layer DW + GG). How big of mistake (if at all) is this?

Thanks for all your help!
Tom

Brian -
You mention this often ....



I am planning to run my ceiling hat channel parallel to minimize loss of height (I expect to come it at about 7.5' or less after 2 layer DW + GG). How big of mistake (if at all) is this?

Thanks for all your help!
Tom

Hey Tom,

how can you run hat channel parallel to the joists? I beg yoru pardon if i'm being dense, but i can't picture it. Unless you are using RSIC clips?

If using clips, then no worries at all about orientation of the channel. none whatsoever.

if using joist/furring_or_hat_channel/drywall, then i always say perpendicular for these raesons

1. gives you the chance to put the furring 24" OC instead of 16" OC. if the joists are already 24" Oc, then don't bother with furring or hat channel

2. it's the only way to really screw it up, as otherwise you would only be screwing one side of the hat channel to the joists.

Brian

As Brian said, no problems running parallel if you are using RSIC Clips. I used the RSIC-1 Ext 04 to minimize the loss of ceiling height, as demonstrated by the following graphic:

http://i25.photobucket.com/albums/c62/bclasen/Misc/rsic-1ext04-min-max-drop.gif

I have low ceilings, with RSIC, hat channel, 2 layers of drywall (1/2" & 5/8") and a Dricore floor, my finished height is (as I recall) around 80". I wish I had your 7.5'! If I had that much room, I would use the method in the following graphic as it would be much faster and easier (putting the sister brace on the side of the joist was a bit of a pain). That being said, I'm glad I went that way because of my height. But if I had over 7.5', I'd go:

http://i25.photobucket.com/albums/c62/bclasen/Misc/rsic-1ext04-4inch-drop.gif

Now I wouldn't use the full 4", but by snugging up the clip, you would lose 1 5/8", plus the height of the channel. This way you would also be able to run either parallel or perpendicular.

Bob

........build a wall in front of the two concrete walls with 2x4's. (1 inch away?)


This is in no way directed towards Brian but I get concerned every time I see someone post the above recommendation. While I understand the acoustical reasons for this I'm not sure everyone thinks about the safety implications. By building a wall such that an enclosed cavity is created you now have a path for fire to spread quickly from one end of a room to another. Additionally, depending on your design, you create a path for fire to instantly go from the wall into the ceiling.

Assuming people are building to code and getting inspections, many locations require fire blocking every 10 feet (horizontally and/or vertically). On the longest wall in my basement, had I built 1 inch in front of the wall, I would have ended up with an 8' x 46' path for fire.

Hopefully this never becomes an issue for anyone here (or anywhere else) but I know I'm keeping safety in mind for my family.

Mike

Brian and BasementBob -

I guess I should have mentioned that, YES, I am using RSIC. But the question was answered anyway. Not only are you guys geniuses, but mindreaders as well! Nice to know my plan is in line with your recommendations. The area of my theater where the screen will be sits under a sunken family room so I am trying to keep the difference in height between the full 8' area and the lower area as small as possible. As I said, I expect to have less than 7.5 when through. Otherwise, my room seems to be very similar to BBobs (dricore, etc).

mbkitner -

Isn't that what inspections are for?

Thanks for your help,
Tom

This is in no way directed towards Brian but I get concerned every time I see someone post the above recommendation. While I understand the acoustical reasons for this I'm not sure everyone thinks about the safety implications. By building a wall such that an enclosed cavity is created you now have a path for fire to spread quickly from one end of a room to another. Additionally, depending on your design, you create a path for fire to instantly go from the wall into the ceiling.

Assuming people are building to code and getting inspections, many locations require fire blocking every 10 feet (horizontally and/or vertically). On the longest wall in my basement, had I built 1 inch in front of the wall, I would have ended up with an 8' x 46' path for fire.

Hopefully this never becomes an issue for anyone here (or anywhere else) but I know I'm keeping safety in mind for my family.

Mike

Hi Mike,

always nice to see a safety oriented post. the best thing to do with any concerns is take them to the lcoal office & ask somebody. I always recommend that people talk to their code offices. There are reasons outside of safety as well, including potentially the value of homes.

if one could not build a wall with a continuous path (such as studs 1" from concrete), then Green Glue would become the only viable sound isolation product anywhere. Clips? make such a path. channel? makes such a path. staggerd or double studs? make such a path.

but those types of walls are fire tested, and approved/used every day. Now vertical fire paths are no-no's, of course.

i say again - i am not a building code guru, but talk to your local office and ask them if they have any requirements or concerns about a decoupled wall. It isn't likely that they will.

Brian

Isn't that what inspections are for?

Sure but it's nice to check your local codes before the inspections so you can build it right the first time.

if one could not build a wall with a continuous path (such as studs 1" from concrete), then Green Glue would become the only viable sound isolation product anywhere. Clips? make such a path. channel? makes such a path. staggerd or double studs? make such a path.

but those types of walls are fire tested, and approved/used every day. Now vertical fire paths are no-no's, of course.


Brian, as usual you bring up some really good points. I hadn't really considered the results of clips, staggered studs, etc. However I do believe there are potential issues here depending on location. While I have no personal experience with horizontal fire paths, I have read of individuals failing an inspection because of horizontal paths exceeding 10 feet. On the flip side, many people interpret the 10 foot rule as applicable in the vertical direction only. Are they right? Are they wrong? Overzealous inspectors? Varying local codes or interpretation of the codes? Maybe. I don't know and won't pretend to know but I would encourage (as you did) everyone to check with their local office before committing the time and money to construction that may have to be redone. If someone chooses to build sans inspections....well that's another thread. ;)

As for vertical fire paths, definitely a no-no and typically this isn't an issue as most walls are less than 10 feet tall. However, in the process of building soffits and/or using isolation construction methods it is very easy to bridge the ceilings and walls if not paying attention. It's typically a simple fix, but easily overlooked.

On the subject of soffits imagine the following.....

A 2x4 wall is framed and prior to installing drywall a 2x4 soffit is built. At the bottom of the soffit a 2x4 is used as fire blocking to isolate the lower portion of the wall from the upper portion. However the 10 inch upper portion of the wall (small section above the fire blocking) that shares framed space with the soffit is bridged to the ceiling by the soffit. Since this portion of the wall is isolated by the fire blocking is it now NOT part of the wall and technically part of the soffit? And then by extension part of the ceiling?

Mike

hey Mike,

you raise a very nice piont (i think i said that before). my basic philosophy is to at all times tell people to ask their local office. i don't ever - or i try not to, anyway - answer questions about construction, i just say contact somebody that can stamp "approved" on your plans...

if you wind up talking to your office about these issues, might be interesting to hear what they have to say.

Brian

Brian,

Ceiling? 2x4s decoupled or hat channel on floor joist

--------------------------------------------------------------------------------

Just in the planning stages of my dedicated home theater construction. In the basement, I have a 19.5' x 14.5' room, 8' from floor to bottom of main level floor joist. Front and left wall are bare concrete, rear and right wall are studded and rocked. I plan to move in 1" from each wall and erect a decoupled stud wall which will be covered with 2 layers of rock sandwiching Green Glue.

Ok, finally to my question. Would it be best to lower my ceiling by 5 inches and have 2x4s decoupled from the bottom of the floor joist, or should I use hat channel connected to the bottom of the floor joist?

If I go the decoupled route and use 2x4s, what would the spacing requirement be to support 2 layers of rock and GG on a 14' span?

Thanks for any advice/response.

Dedicated Theater Novice Builder
Matt

hey clipper,

man, 20 pages. well, since 20 pages it is, perhaps a little summary of some points that aren't covered that thoroughly herein is in order

-the use of furring strips in the form of 1x4 or 1x3 wood strips, or metal hat channel, perpendicular to the studs/joists and spaced 24" on center can nicely improve performance for almost no cost. in combination with Green Glue or other forms of damping, this is particularily effective. ....

-the use of 24" on-center studs will help basically all types of walls perform a little better. for all walls, 24" OC is a little better than 16" OC. no need or desire for furring fi you use 24" OC studs (it doesn't hurt, but doesn't help as much). if you're studs are 16" OC, don't panic, if they are closer together than 16" OC, use RSIC clips (instead of or in combo) or furring (in combo with) Green Glue.

ok, onto your post.

1) Vapor barrier on concrete, then build a wall in front of the two concrete walls with 2x4's. (1 inch away?)
2) insulation, GG on joists on ceiling, then 5/8" drywall, GG, and then 1/2" drywall
3) some kind of insulation on concrete walls, then GG on studs, 5/8" drywall, GG, then 1/2" drywall.
4) Same on the other two non-concrete walls

1) is the ideal situation for concrete. concrete / space / studs/drywall.
2. i recommend using furring as mentioned above, so little cost, nice gains
3) perfect, no need for exotic insulation
4) perfect, still no need for exotic insulation, but you could improve things should you deem it necessary, by utilizing staggered stud or double stud walls (a little more space, a little more cost)....
Brian
Ok So the furring strips act as a "poor man's" hat channel, is that correct?
So many times I hear "check with your code requirements". Sorry for the stupid question, I'm not a pro,where do I do this? City? County?
Will drywallers look at me like I'm on crack when I ask them to put this Green Glue sandwich up?
Just the rantings of a rank amateur....
CC

I'd like to chime in on CC's question.

How much greater benefit would it be to use RSIC and hat channel/GG/drywall vs not using the RSIC and using just the hat channel/drywall?

Also,

How much difference between using just hat channel vs furring strips with GG between the furring strip and the floor joist?

If there isn't a great difference between the 3, I guess I would lean towards just using GG/1x3 furring strips/GG/Drywall/GG/Drywall?

I think the use of the furring strips would make all phases of the construction easier, especially when putting in a mdf soffit after the drywall is completed.

Any thoughts/advice?

Brian,

Ceiling? 2x4s decoupled or hat channel on floor joist

--------------------------------------------------------------------------------

Just in the planning stages of my dedicated home theater construction. In the basement, I have a 19.5' x 14.5' room, 8' from floor to bottom of main level floor joist. Front and left wall are bare concrete, rear and right wall are studded and rocked. I plan to move in 1" from each wall and erect a decoupled stud wall which will be covered with 2 layers of rock sandwiching Green Glue.

Ok, finally to my question. Would it be best to lower my ceiling by 5 inches and have 2x4s decoupled from the bottom of the floor joist, or should I use hat channel connected to the bottom of the floor joist?

If I go the decoupled route and use 2x4s, what would the spacing requirement be to support 2 layers of rock and GG on a 14' span?

Thanks for any advice/response.

Dedicated Theater Novice Builder
Matt

Matt,

without a doubt, seperate ceiling joists represent the ultimate use of Green Glue and would beat hat channel to the ceiling. They are the most difficult, at least in many cases, construction possibility as well - seperate ceiling joists, that is.

if seperate joists for the ceiling aren't a good realistic option for you, the next best choice (for ceilings) are spring hangers like kinetics ICW or modern sound clips that have lab tests to back them (like RSIC or ISOmax).

all that said, furring or hat channel on the joists does make a very good ceiling, and alot of AVSers have used such an assembly and might be able to offer some feedback. we have certified lab data for walls (though floor/ceiling tests are just getting undrway)

Brian

Ok So the furring strips act as a "poor man's" hat channel, is that correct?
So many times I hear "check with your code requirements". Sorry for the stupid question, I'm not a pro,where do I do this? City? County?
Will drywallers look at me like I'm on crack when I ask them to put this Green Glue sandwich up?
Just the rantings of a rank amateur....
CC

on ceilings, you could look at hat channel as a poor mans sound clip, or poor mans ceiling hanger, etc, yes indeed.

not a stupid question at all - call the local city inspection/permit office and they'll be able to answer all of your questions. look in the gov't section of the yellow pages

I'd like to chime in on CC's question.

How much greater benefit would it be to use RSIC and hat channel/GG/drywall vs not using the RSIC and using just the hat channel/drywall?

well, the answer to that is this:

the RSIC assembly will perform worse around the mass-spring resonance of the decoupled partition (RSIC will create a truely decoupled partition subject to mass spring behavior), and it will be better at higher frequencies. So it's a tradeoff of deep bass -vs- higher bass in a way, as all of the above are good for mid/high frequency sounds.

where the tradeoff occurs depends on where the mass-spring resonance occurs - the lower this resonance is in the RSIC system the more the advantage tips towars the clips. So, for example, on a wall the advantage of clips isn't great for theaters, but on a ceiling (much deeper cavity), we anticipate the clips to have a distinct advantage. also, though we've not begun testing impact noise in formal lab setting as of yet, it is my anticipation that the clips will be preferable for impact noise.

in the absence of damping, the clips should be considered vastly preferable, i entered some comments about this in a thread about cellulose -vs- fiberglass earlier today.

basically, it is a tradeoff of deep bass -vs- upper bass, and often in the real world flanking will define middle and high frequencies, but if flanking isn't a problem at middle/high freq's the clips will perform better there as well. lab data is available for walls only.




Also,

How much difference between using just hat channel vs furring strips with GG between the furring strip and the floor joist?

If there isn't a great difference between the 3, I guess I would lean towards just using GG/1x3 furring strips/GG/Drywall/GG/Drywall?

I think the use of the furring strips would make all phases of the construction easier, especially when putting in a mdf soffit after the drywall is completed.

Any thoughts/advice?

furring is nice to work with.

hat channel -vs wood furring = pick your poison, no particular advantage either way, both work nicely.

Brian,

Thanks for your helpful responses, most likely I'll go with the furring strips for ceiling support and decoupled (double) stud side walls.

While I've got your ear (monitor), my next question relates to floor treatment.

As stated before, this is a basement theater and I'll be starting with a bare concrete floor. The room adjacent to the theater in the basement is just a play/family room. The bedrooms are about 17 feet away.

Do I need treat the floors with anything or just have a thick pad and plush carpet?


Thanks,
Matt

It seems like the Audo Alloy site is no longer or am I having some type of glitch. When I go to audio alloy's site I get get a server not found message. Did they close shop? UPDATE: The problem is on my end probably a DNS nameserver problem. I can go to the site if I convert audioalloy.com to an IP number.

Thanks,
Dave

http://www.audioalloy.com/index.html
works fine for me

I appreciate the notice. I'll have it looked into. Sorry for any inconvenience. Feel free to e-ask or PM with any questions.

Brian,

Thanks for your helpful responses, most likely I'll go with the furring strips for ceiling support and decoupled (double) stud side walls.

While I've got your ear (monitor), my next question relates to floor treatment.

As stated before, this is a basement theater and I'll be starting with a bare concrete floor. The room adjacent to the theater in the basement is just a play/family room. The bedrooms are about 17 feet away.

Do I need treat the floors with anything or just have a thick pad and plush carpet?


Thanks,
Matt

Matt,

my recommendation is to try it and see. (with respect to the floor).

Build your assembly and take a quick assessment of noise in the rooms to the sides, and then try to discern what's coming from where (doors, ducts, floor) as best you can, and decide then if you need more $$$ and more upgrades to the slab. IF that's not feasible, then it's just not feasible, but if it is something you could do that can be advantageous

the double stud walls will be limited by flanking noise at mid/high. This is almost a certainty as the potential of that type of wall is so extremely high. So, if ultimately you wanted to squeeze the most you could possibly squeeze out of a double stud wall, then the slab would have to be dealt with, no question.

good luck,

Brian

Brian,

Given the following two scenarios for a basement:

1. Double drywall on walls and ceilings with GG on all stud faces and between drywall layers.

2. Double drywall only on the ceiling and a single layer on the walls with GG on all stud faces and between the ceiling layers.

How much does option #2 compromise the sound isolation? I know flanking noise would be an issue here but I'm trying to quantify the value in doing the walls. This is a ~1700 square foot basement so doing the ceiling and walls with double drywall would get pricey.

Mike

Brian,

Given the following two scenarios for a basement:

1. Double drywall on walls and ceilings with GG on all stud faces and between drywall layers.

2. Double drywall only on the ceiling and a single layer on the walls with GG on all stud faces and between the ceiling layers.

How much does option #2 compromise the sound isolation? I know flanking noise would be an issue here but I'm trying to quantify the value in doing the walls. This is a ~1700 square foot basement so doing the ceiling and walls with double drywall would get pricey.

Mike

Hey Mike,

Option #2 would be a big compromise to the sides. How much of a compromise that is going up (sound isolation to the upstairs) is a question of flanking noise, and depends on your structure and the like.

You might consider 50% coverage of Green Glue to reduce costs and still treat the whoel room? use less glue, save $$$, get much closer to option 1 than to option 2. Also, if the $$$ are an issue, put it between layers and not on stud faces (if the stud faces adds up to enough to save significant $$$). certainly furring > GG on stud faces for improvement at low cost.

let me know if that made sense,

Brian

If anyone is looking to split a case, please contact me. Does not have to be exactly in half.
If anyone is looking to sell please contact me. rlui@victoria.tc.ca

Option #2 would be a big compromise to the sides. How much of a compromise that is going up (sound isolation to the upstairs) is a question of flanking noise, and depends on your structure and the like.

Thanks for the feedback Brian. I'm not very concerned about compromising to the sides. My major concern is sound isolation to the upstairs. What specific structure information would help you quantify this? I realize it's somewhat a WAG. Here are some basics:

Basement walls are poured concrete.
Framed walls are 2x4 16" OC with double top plates.
Top plates are in contact with joists (or nailers).
Wall cavities will be filled with fiberglass insulation.

Anything else?

Mike

Thanks for the feedback Brian. I'm not very concerned about compromising to the sides. My major concern is sound isolation to the upstairs. What specific structure information would help you quantify this? I realize it's somewhat a WAG. Here are some basics:

Basement walls are poured concrete.
Framed walls are 2x4 16" OC with double top plates.
Top plates are in contact with joists (or nailers).
Wall cavities will be filled with fiberglass insulation.

Anything else?

Mike

Hi Mike,

i'm not brave enough to guess at what the flanking situation in any given place will be, lots of variables. in addition to structural flanking (that GG can help alot with), there are ducts and doors and seal quality, etc.

If it was my situation and i was handling it, and i wanted to keep $$$ down, i'd skip GG on studs/joists and replace with hat/furring as for 1) the hat/furring is far more effective and for 2) it might be cheaper (or might not, i guess). I'd also opt for 50% coverage on the walls, and i'd consider not putting GG in front of the concrete.

now, concrete + studs with drywall creates a resonance that is just begging to be damped, and that is a good place to use GG, BUT, the sheear mass of the concrete goes a long way towards helping. If the studs in front of the concrete are rigidly attached to the rest of the structure, 50% GG might be something to consider.

Also, if your construction process allows you the chance to sort of build the room, test it, and upgrade it later if need be, that is always a nice luxury. As if it works during the preliminary test, then great, no need for more work time or $$$

Brian

Brian, I noticed your site has spot for 'Discount Coupon' code to be entered. Is there any discount code offered to AVS members? Is there any way to obtain such a discount code?

I don't recall seeing anything mentioned before but there are many many posts so I may have missed it.


Regards,
Doc

Hi Doc,

You can contact Audio Alloy, and you have a PM :)

Thanks Ted.

-------------------
Doc

I'm considering using green glue. I want to be able to watch movies without disturbing neighbors. I think LF from my SVS would be the main issue. Right now i have the ceiling and one wall that faces the neighbors home exposed with new insulation installed. I'm ready to install the drywall. I was looking at MLV as well.

Don't bother with MLV. It provides less benefit than an additional layer of 5/8" drywall at a whole bunch more cost.

thanks Dennis. I have a question about green glue. Would I be able to use the green glue on a textured wall. The previous owner of my home used some type of plaster to make swirl designs on the wall, and so 2 of the walls are not smooth. The sandwich would be:
uneven wall/ green glue/ new 5/8 drywall

Hey Green Gluers...

I have what may be a silly question but will GG actually bond something?

Here's my situation - I have this return in my ceiling:

http://www.reedsplace.com/returnsm.JPG

I've gone to all the trouble to de-couple everything and am going with two layers of drywall and GG sandwich, but now I've got this huge hole in the whole thing that will only have a thin layer of sheet metal between the room and the ceiling cavity. So, what I was thinking was two fold:

1) line the inside with linacoustic - that's easy

2) make a sandwich of acoustic ceiling tiles (or sheetrock) with GG between two layers of this material and then green glue it to the top of the return (on the outside of the metal box. This would add mass to the thin metal and some damping. But, will the GG actually bond that sandwich to the metal box...?

Brian...anyone...?

Brian has stated in the past that GG is not meant to be or recommended as an ashesive BUT that doesn't mean what you're proposing wouldn't work.

I don't know exactly where you're mounting this sandwich to the conduit but I assume it is the open area in your pic.

What do you think about this suggestion:

Are you hanging the ceiling drywall directly to the ceiling joist?
It looks like you are from the position of the outlet and the can lights.
If so, adjust the depth of the conduit and your sandwich so that it is flush with the top\inner side of the ceiling drywall.
Hold it in place with some real duct tape and just before you hang that piece of dryall, slather some GG on the outside of your sandwich(tough part), hang the drywall, and put four screws through the ceiling drywall into your freshly GG'd sandwich.
Or instead of putting the GG on the bottom of the sandwich, you could measure the position of the sandwich rectangle in relation to the ceiling drywall, like you do for outlets etc. and put the GG on the drywall just before you hang it.
Make sure the screws are short so they don't penetrate into the conduit space.
Trust me, GG and those screws will hold it there.
Voila, you'll ultimately have 4 layers of GG'd drywall covering the hole.

One question, why is the conduit open to the room and why is it there at all.
Feeding the next floor above?

Thanks, Milt but that's not a conduit - that's the return air for the theater (it doesn't connect to any other room so I'm not concerned with sound traveling down the air duct, just through the thin sheet metal). So the hole has to be there. I was talking about putting my little GG sandwich on top of the metal box (the other side of it if you could stand above and look down at it). This will add mass and dampening to the thin sheet metal that makes up the return cavity itself. Make sense...?

ebr,

If you don't box in your can lights to control flanking noise, the cold air return will not matter.

Can you line the return with two layers of dry wall w/GG between? If you can, seal it to the ceiling dry wall to prevent sound migration.

I hear you, but I see that return as a MUCH larger problem (literally) than the cans. The cans have 4" diameter holes that are actually sealed with a couple of layers of metal and an air space between. That return is 30x14 and just thin sheet metal.

I can line the top of the return with either drywall or ceiling tiles sandwiched with GG. The sides are attached to and flush with the ceiling joists so I can only line the inside with linacoustic.

Hopefully, this will help mitigate any issues. Thanks.

P.S. There will still be no contact between the return box and the floor system above and that cavity will be filled with insulation.

thanks Dennis. I have a question about green glue. Would I be able to use the green glue on a textured wall. The previous owner of my home used some type of plaster to make swirl designs on the wall, and so 2 of the walls are not smooth. The sandwich would be:
uneven wall/ green glue/ new 5/8 drywall


yes, you can. i looked a bit this evening, but couldn't find, for a thread where this was discussed in detail notn too long ago. i'll take another peek.

you can use these options

a) use more glue to fill the texture (costs more, won't hurt performance up to 3 tubes/sheet (3 tubes is a little better than 2, but only recommended for persons totally disconcerned about money), more than 3 tubes/sheet and performance goes down, so that's really not recommended)

b) sand the texture down or fill it with drywall mud (time consuming)

c) paint GG (roller) onto the wall, let dry (a few hours), then when applying drywall to the existing wall, trowel a generous portion of setting type drywall mud into the drywall and smash that against the dried GG. This doesn't waste money, or take an exorbitant amount of time, and you get better performance, actually, than a normal install.

d) if the texture isn't severe, just carry is as you would

hope those made sense & helped

Hey Green Gluers...

I have what may be a silly question but will GG actually bond something?

Here's my situation - I have this return in my ceiling:



I've gone to all the trouble to de-couple everything and am going with two layers of drywall and GG sandwich, but now I've got this huge hole in the whole thing that will only have a thin layer of sheet metal between the room and the ceiling cavity. So, what I was thinking was two fold:

1) line the inside with linacoustic - that's easy

2) make a sandwich of acoustic ceiling tiles (or sheetrock) with GG between two layers of this material and then green glue it to the top of the return (on the outside of the metal box. This would add mass to the thin metal and some damping. But, will the GG actually bond that sandwich to the metal box...?

Brian...anyone...?

Hey EBR, i fear i didn't notice this post until just this evening.

My recommendation is to not rely on GG to bond to the ductwork over all of time. and my reason is we haven't tested long term metal adhesion. i suspect it would stick and hold eternally, but i can't recommend it.

it is a VERY good idea to put some mass over that large sheet metal surface, and i really do recommend the line of thought that you are having. perhaps you could make a sandwich of drywall and screw it to the duct (to blend in with the rest of the wall?). Perhaps the mass/GG could go inside the duct? Perhaps you could use GG and augment with a simple fastener or two?

I hear you, but I see that return as a MUCH larger problem (literally) than the cans. The cans have 4" diameter holes that are actually sealed with a couple of layers of metal and an air space between. That return is 30x14 and just thin sheet metal.

I can line the top of the return with either drywall or ceiling tiles sandwiched with GG. The sides are attached to and flush with the ceiling joists so I can only line the inside with linacoustic.

Hopefully, this will help mitigate any issues. Thanks.

P.S. There will still be no contact between the return box and the floor system above and that cavity will be filled with insulation.

isolation can be attained without boxing the cans. i would wager (virtually a certainty) that cans are most problematic at mid/high frqeuencies and not low.

this opening is probably big enough to be a pest at low.

ebr,
Jeez what a dope I am, must have been late.
So how about this,
build a box that fits inside of the return. A box in a box.
The box could be 2 layers, one 1/2" mdf and the other drywall with GG in between.
That way the drywall will have a structure to provide form and you can put another layer of GG between the return and the box.
With the MDF you can run screws into the joists and not have to worry about screws through the top of the return.
The inner box would cut down on the return opening but at 30 x 14 you shouldn't have a problem and the duct looks like it can handle a decent air flow.
Actually you could use all drywall too.
Make the top piece fit exact, apply GG all around, fit the top piece first and screw drywall to the sides of the return and they will hold the top drywall piece in place. Double that up all around and it would seem to be about as good as you can do.
HTH

Hey EBR, i fear i didn't notice this post until just this evening.

My recommendation is to not rely on GG to bond to the ductwork over all of time. and my reason is we haven't tested long term metal adhesion. i suspect it would stick and hold eternally, but i can't recommend it.

it is a VERY good idea to put some mass over that large sheet metal surface, and i really do recommend the line of thought that you are having. perhaps you could make a sandwich of drywall and screw it to the duct (to blend in with the rest of the wall?). Perhaps the mass/GG could go inside the duct? Perhaps you could use GG and augment with a simple fastener or two?

Hi Brian,

To continue on the GG as the only bonding or glue layer. I'm envisioning using GG for some doors I will be constructing. It will be a sandwitch construction made out of 5 leafs (10mm MDF, 16mm OSB, 16mm MDF, 16mm OSB, 10mm MDF). Total thickness about 68mm and weight of the door will be about 200 punds. I will use screws and regular glue going from each side of the OSB into the central MDF layer. I was then going to use GG to glue the outside mdf layers to the core. Outside layers are about 29 pounds each. I don't want to screw into this layer since it will be painted and I don't want to do additional finishing work to hide the screws. Could GG be used to hold the outside leafs without screws?

Another way of doing it is to use GG between the OSB and central MDF layers. I could then use screws on these layers. I would then use a high performance glue to glue the outside mdf layers.

Which approach is better for GG performance but also good practice?

Cheers,

Exipnos

Hi Brian,

To continue on the GG as the only bonding or glue layer. I'm envisioning using GG for some doors I will be constructing. It will be a sandwitch construction made out of 5 leafs (10mm MDF, 16mm OSB, 16mm MDF, 16mm OSB, 10mm MDF). Total thickness about 68mm and weight of the door will be about 200 punds. I will use screws and regular glue going from each side of the OSB into the central MDF layer. I was then going to use GG to glue the outside mdf layers to the core. Outside layers are about 29 pounds each. I don't want to screw into this layer since it will be painted and I don't want to do additional finishing work to hide the screws. Could GG be used to hold the outside leafs without screws?

Another way of doing it is to use GG between the OSB and central MDF layers. I could then use screws on these layers. I would then use a high performance glue to glue the outside mdf layers.

Which approach is better for GG performance but also good practice?

Cheers,

Exipnos

Expinos,

yes, the MDF will hold the outer layers. adhesion is tested and very good for wood products, drywall, etc. - we've tested it on the things it's basically intended for use with.

you may be well served to screw the OSB as it's applied, however, as it might warp otherwise. gg has water, which can cause problems with some wood products in "free" laminates (i.e., when no fasteners are present). if the wood tries to warp before the glue is strong, it can pull itself apart.

Brian

Milt, some good ideas there.

I know I,ve seen the answer to this before, but could please someone remind me The drying time for green glue? I mean how long can you wait after spreading it before it is too dry to screw the dywall? Can I spread it on 2 or three pieces of drywall, and then screw those pieces to the wall? or will it get too hard before I,m finished?

-Sorry, double post...

Hi Stef,

Try and get the Greened board sandwiched withing 20 minutes. 10 minutes is better.

Hi guys,

I already have drywall up which has a texture finish. Is it ok to GG it then add the second layer of Drywall over it? Or would you recommend removing the original drywall with texture finish and start fresh? I'm only asking as the drywall is already there. Much appreciated.

Hi guys,

I already have drywall up which has a texture finish. Is it ok to GG it then add the second layer of Drywall over it? Or would you recommend removing the original drywall with texture finish and start fresh? I'm only asking as the drywall is already there. Much appreciated.

If it is a standard mild texture, you can go with these options

1) use GG in the normal manner. The impact here is simply that the texture results in more GG in areas, and the GG doesn't spread as much. performance would be between GG and 50% coverage with GG. i.e., performance would still be good

2) use a little extra GG. this raises costs, but compensates for the texture and yields performance in line with or a bit better than standard 100% coverage with GG

3) scrape the texture or fill it with a skim coat of drywall mud

4) paint with a roller GG over the surface of the texture, then trowel durabond 90 onto drywall and apply it over the dried GG. the durabond will fill the texture, and you'll have a uniform GG film with great results. This will perform a little better than normal for two reasons. 1) the GG is dried when constrained (long story) and 2) the drywall mud adds a little weight

If it is a more severe texture, like popcorn, i recommend scraping it down to a standard texture and proceeding as above.

option 4) is more work, but can be used over any texture.

good luck & let me know if that was unclear

Brian

Brian,
If I understand you, this is prep for another payer of GG and drywall, correct? I would also like to comment to anyone using Durabond 90, it is VERY hard and does not sand very well. Make sure you get a smooth a surface as possible, if not you are in for alot of post skim coat work. If if this is simply a prep layer, I might suggest setting type mix, maybe 45, rather than Durabond 90. I will typically use DB 90 for a brown or scratch coat for plaster walls, not the top.

Anyway (4) is a very interesting concept

Thanks Brian for your suggestions.

I actually ran this over with the wife (financial management of course) and she also suggested to fill it with drywall mud to smooth it out. That probably sounds best since it'll get the most performance out of GG which we can't afford to expense. Thanks.

Brian,
If I understand you, this is prep for another payer of GG and drywall, correct? I would also like to comment to anyone using Durabond 90, it is VERY hard and does not sand very well. Make sure you get a smooth a surface as possible, if not you are in for alot of post skim coat work. If if this is simply a prep layer, I might suggest setting type mix, maybe 45, rather than Durabond 90. I will typically use DB 90 for a brown or scratch coat for plaster walls, not the top.

Anyway (4) is a very interesting concept

prep for a textured wall (or a rather/significantly textured wall).

if the walls are smooth, or only faintly textured, you can proceed w/o this concern. And of course with new drywall you can proceed w/o these steps as well.

good tips on the durabonds.

:)

Thanks Brian for your suggestions.

I actually ran this over with the wife (financial management of course) and she also suggested to fill it with drywall mud to smooth it out. That probably sounds best since it'll get the most performance out of GG which we can't afford to expense. Thanks.

you're welcome & good luck. don't hesitate to post or write.

Q1. The install instructions state "Acceptable tip openings range from 1/8 to 3/8...". Any pros/cons on the various sizes?

Q2. I'm doing the 50% method (or 1 tube per 4x8 sheet) - is there a method to applying this to ensure proper coverage with simple, repeatable, instructions? For instance, apply a 3/8 bead to create a 6" grid pattern. Can you tell I'm at the stage where I need to explain this to the drywall crew? [Yes, they've seen the official instructions...]

Q3. Oh yeah: Should I expect to purchase these tips at the local hardware store? My contractor seems to think they should have come with the GG.

Thanks,
James

The tips should be in with the GG. Mine were. Look down in the popcorns...

If you don't have them, contact AA and I'm sure they'll do you right. As far as application goes, just tell them to "squiggle" it on like in the pictures in the instructions. Watch them if you can because after a few sheets, they'll start to cheat.

Duh - I checked the other boxes and they all have tips in them, so most likely I have one set that walked off to some corner of the garage.

Thanks,
J

Q1. The install instructions state "Acceptable tip openings range from 1/8 to 3/8...". Any pros/cons on the various sizes?

well, its possible that more closely spaced beads that were thin (1/8") might give a more uniform coverage, but GG squishes out very easily, and larger beads (easier / faster to apply) work well. in the lab tests a photo of the beads is shown, they are moderate in size. you can download the reports at www.audioalloy.com and take a look.

at low freq's the bead size will be fairly unimportant.

Q2. I'm doing the 50% method (or 1 tube per 4x8 sheet) - is there a method to applying this to ensure proper coverage with simple, repeatable, instructions? For instance, apply a 3/8 bead to create a 6" grid pattern. Can you tell I'm at the stage where I need to explain this to the drywall crew? [Yes, they've seen the official instructions...]

yep, what you want to do is target 100% coverage over 50% of the sheet, so to speak, like shown on a bit on page 6 of this page: http://www.audioalloy.com/greenGlueApplication.pdf

leave some space without damping material, and fill the rest, basically. Its not a "make or break" thing, and i doubt you could find a way to install it where the benefit was badly compromised except by extremely senseless techniques, like putting all the glue in a massive blob right in the middle.

let me know if that wasn't clear enough.

Q3. Oh yeah: Should I expect to purchase these tips at the local hardware store? My contractor seems to think they should have come with the GG.

Thanks,
James

i see you found the tips! thank goodness. :)

A local and highly respected acoustician is advising me to use SikaFlex rather than Green Glue. He claims to have used both and says "SikaFlex is just as good". So, anyone in here have any experience with both and want to weigh in?

A local and highly respected acoustician is advising me to use SikaFlex rather than Green Glue. He claims to have used both and says "SikaFlex is just as good". So, anyone in here have any experience with both and want to weigh in?
Ask him to show you the certified laboratory transmission loss tests on this product. These labs tests will include the details of wall construction, application of material, etc. "Just as good" has no meaning unless you have data to back it up.

- Terry

I guess it's not surprising that this gets asked once in a while. Both caulk and green glue come in tubes.

Ask him to show you the certified laboratory transmission loss tests on this product. These labs tests will include the details of wall construction, application of material, etc. "Just as good" has no meaning unless you have data to back it up.

- Terry

I understand that for multi-million dollar projects where you need someone to sue if things go wrong this kind of thing is important. But, just because something lacks the lab results doesn't mean it doesn't work. If you don't really know, how can you say? I would love to perform my own informal tests building a window plug with GG and with SikaFlex and using my own ears to see if I can detect a difference outside the window, but I don't want to buy a whole case of GG to do the comparison. Does anyone know anyone in the Seattle, WA area that might have an extra tube of GG I could buy off them?

Well Mr. Cool Guy....
A couple of points:
First, if he really is highly respected acoustician (degrees, certifications and all), he would not say "just as good as" unless he had the test results to back up that statement. If he doesn't have the test results, and still says "just as good as" either the "respected" part or "acoustician" of that phrase should be seriously questioned.
Second, the manufacturer (yup, actually talked to them) claims the product is an adhesive and sealant and is not designed for, or intended for, acoustic damping applications. Green Glue is not an adhesive...it is a damping agent.

Sika DOES make a damping product called SikaDamp and is used only in the automotive industry and mostly as a surface application (rather than CLD). The also have SikaBaffle ... again for the automotive industry. Neither of these products has been tested for, or intended for use in, the home construction industry and more particularily as a CLD material between layers of drywall.

Well Mr. Cool Guy....
A couple of points:
First, if he really is highly respected acoustician (degrees, certifications and all), he would not say "just as good as" unless he had the test results to back up that statement. If he doesn't have the test results, and still says "just as good as" either the "respected" part or "acoustician" of that phrase should be seriously questioned.
Second, the manufacturer (yup, actually talked to them) claims the product is an adhesive and sealant and is not designed for, or intended for, acoustic damping applications. Green Glue is not an adhesive...it is a damping agent.


OK well... first off, the "highly respected acoustician" I am working with may not have meant "just as good for all applications" but rather "just as good for my specific application". Why would he need lab data to make that statement if he had direct experience with both products? Also, whether or not the product was "intended" for use in acoustical applications still doesn't mean it doesn't work for them. In fact, I have built a window plug with the sikaflex and it works pretty darn good.

As a musician on a budget I would like to test the GG in the same application to see if using the "intended, lab tested" product actually performs better for me, but there is an exorbitant financial barrier to entry for an unknown percentage of improvement (if any). Perhaps poor musicians seeking to treat an existing space on a budget are not the target market for GG, which is unfortunate since I bet there are millions of us out there.

In any case, there is no need to argue because, as far as I know, none of you have actually used SikaFlex and GG to build window plugs. If any of you are sympathetic to my plight and would like to hook me up with a tube of GG please let me know. The company that makes GreenGlue is not willing to sell me a single tube. I won't let their customer service affect my judgement of their product quality. I am still open to evaluating GG. That's basically all I am looking for right now. ONE tube of Green Glue to construct a window plug to compare to the one I made using SikaFlex. Thank you.

SikaFlex and GG to build window plugs
Yes I have. Each of those materials has been designed for a completely different application and use. GG will not work as a sealant and SikaFlex will not work as a damping agent. Period.

Why would he need lab data to make that statement if he had direct experience with both products?
...because a 'high respected acoustician' wouldn't stay highly respected for long if he/she started making product recommendations without having first seen the certified lab results and since they would have seen them, they'd have them available for you.

...because a 'high respected acoustician' wouldn't stay highly respected for long if he/she started making product recommendations without having first seen the certified lab results and since they would have seen them, they'd have them available for you.

Right, which makes his reccomendation all the more interesting to me since he is and has been highly respected for years in my area and everywhere I call to ask for a local acoustician keeps referring me to him.

I am just totally hearing different things from different, equally reputable sources and it is extremely frustrating. If I could get a single tube of GG it would make this much easier for me. ARRRRRGH!!!!

For some reason I just thought of how really old people use tennis balls on the feet of their walker-devices. Tennis balls weren't designed for that use but apparently they work well for it. I feel like I am debating whether to use tennis balls on my walker or to use the custom designed felt walker foot pads that cost 10 times as much.

Just an observation... soundproofing must be at least a multi-million dollar industry. If silicone, caulk, sikaflex or whatever actually solved an acoustic problem, then why does no one use it (except for this one guy...)?

Any why would the companies that manufacture it not bother to see if a product they already make could be sold for other applications? Especially if they would sell millions at a good margin?

Just an observation... soundproofing must be at least a multi-million dollar industry. If silicone, caulk, sikaflex or whatever actually solved an acoustic problem, then why does no one use it (except for this one guy...)?

Any why would the companies that manufacture it not bother to see if a product they already make could be sold for other applications? Especially if they would sell millions at a good margin?

Question 1: Perhaps due to an entrenched hegemony of reliance upon lab data sheets rather than real world experience?

Question 2: Perhaps they don't realize their product works for that purpose and/or that they could make that much money selling it to a new market?

I will post later when I get home as to the exact product model number of the sikaflex stuff I was reccomended. Maybe AudioAlloy will do the tests and prove that it is lame. If I get some GG I will definitely record some audio outside my window with music blasting on the other side of it so you can hear the difference between the various options.

I think it's because it doesn't work... Simplest and most straightforward explanation.

Perhaps due to an entrenched hegemony of reliance upon lab data sheets rather than real world experience?
No. Because you are spending big $$$ in order to achieve a specific result under specific circumstances and if you're going to be spending $$$ on a product to achieve specific results both you and reputable advisor would want to have reasonable assurance you can achieve that result when you spend the $$$ and without CERTIFIED lab results neither you nor your advisor would have a clue...experience or not. Experience is not helpful unless you've actually measured the results...if you haven't measured the results (with sensitive professional equipment), you don't know if you're getting the bang for the buck that would make one candidate product better than any other candidate product.

Tennis balls? Yup, you can buy a used pocket projector and project against a 150" wide area of white paint and get a picture. If that's the picture that rocks your boat, you're good to go. If not, you wasted $12.00 on the paint and $500 on the projector. I don't feel like throwing away $512.00. ..heck, that's 128 gals of Avgas, that's four hours of flying, that's 944 nautical miles I could go for a hamburger...I wonder what's going on in St. Thomas this weekend. :)

OK so all you Green Glue boosters in here... help a fella out! Someone send me a single tube of Green Glue pretty please with sprinkles on top. :)

MrCoolGuy

If your "acoustician" really means "a guy that sells audio stuff" then he may be confusing the Glue in the name GreenGlue to mean that any sealant, adhesive, bonding agent, glue is the same thing. Ask your "acoustician" what the term viscoelastic means and what properties it has applied between material. If he does not know the answer - then he is "a guy that sells audio stuff". Indeed I think AudioAlloy did test some other materials at their own expense.

http://www.audioalloy.com/soundproofingDampingOptions.pdf

One of my customers may have leftovers if you want to drive down and get a demo tube if you compensate him for it - not sure if GreenGlue took back his unused tubes or not..he had some that leaked in shipping. He might even be nice enough to show you how GreenGlue isolates traffic and railroad noise.

The problem with a demo tube is - it will not prove anything. You could try your window plug test - but unless your flanking issues with the wall around the window and leak issues in designing a removable plug are solved - it will not prove anything. And if your application is indeed a window plug - why bother? The other issues are still going to make it so the kick drum can be heard - just thru the wall rather than the window. But at least you can use the SikaFlex to seal the crack between the drywall and the window - this all assumes your window is not required by egress code....and you are permitted to seal it up.

Brian

Have you considered changing the name to GreenDamp? Never mind ....something green and damp does not sound very healthy...oh wait I live in the NW which is green and damp.

I was going to bring up the same point as Kras - if you are designing a "window plug" especially a removeable one, Its probably not worth your bother to test GG or anything else. Just some added mass in that window may do all that you can do.

BTW - you can test the effectiveness of the SilkaFlex without a tube of GG. Just build a plug out of two layers of drywall (or whatever you're using) and another one out of two layers with the silka in between. Then run your test with both. I fear you will find very similar results because the flanking and seal issues Kras mentioned, are going to be the weak link.

I guess it's not surprising that this gets asked once in a while. Both caulk and green glue come in tubes.

Hi James

i think its just a function of the inventive side of human nature. I'd observe that mass loaded vinyl substitute concepts were pretty common a few years ago when MLV was popular. asphalt or roofing rubber or even other things like pool liners were brought up as concepts for limp mass. basically anything floppy.

and i guess we should all be pretty thankful for the inventive side of human nature, for without it we wouldn't have cars and trucks and things that go, or theaters and all of those. ?

it does get asked quite a bit, but i think thats only natural.



With respect to sikaflex... there are dozens of products under that trade name, most of which are polyurethane materials. Moisture cure one-part products and mix-and-apply two-part systems. I think they also sell mix-and-apply two-part epoxies and acrylics under the sikaflex name, but i could be wrong, i have only a passing knowledge of those products.


on a side note: if you folks ever need to bond anything and have it really, really hold, try a 2-part methacrylate adhesive. They grossly outperform epoxies, and in general will bond anything but things like teflon and polyolefins - which are the slippery plastics you find in milk bottles and rubbermaids and so forth.


but anyway, i couldn't find much about sikaflex pricing, but this page (http://www.jamestowndistributors.com/userportal/search.do?freeText=sikaflex&page=GRID&history=&engine=adwords!6456&keyword=%28sikaflex%29&match_type=) has $7.27 per 10 ounce tube as the lowest cos sikaflex offering. That's about $250 per case of 29 ounce tubes (36 tubes), or alot more than GG.

So if these materials are more expensive, i can't imagine why you'd want to mess with them?

If you opt for a 2-part polyurethane that mixes and cures, be careful as the components of those are sensitizers and should be handled with prudence. they can be handled, but they call for more caution than one-part products. Some one-component polyurethane systems also carry this risk, and some don't. it depends on the cure mechanism of the polymer (if its isocyanate moisture cure or silane moisture cure).

Brian

ok so... I'm going with SikaFlex because I can get it cheap ($5/tube). It is definitely more "damped" than 2 sheets of plywood without the SikaFlex in between (I tested this). Also, I am just going for the 80% solution via cheap patch rather than ultimate solution via complete redesign strategy.

I'm also building a drum riser. Was thinking 4 sheets of plywood glued together with SikaFlex into an 8x8 platform supported by 8 of the 120 pound Kinetics neoprene rubber isolator feet. Any modifications you guys would suggest?

ok so... I'm going with SikaFlex because I can get it cheap ($5/tube). It is definitely more "damped" than 2 sheets of plywood without the SikaFlex in between (I tested this). Also, I am just going for the 80% solution via cheap patch rather than ultimate solution via complete redesign strategy.

I'm also building a drum riser. Was thinking 4 sheets of plywood glued together with SikaFlex into an 8x8 platform supported by 8 of the 120 pound Kinetics neoprene rubber isolator feet. Any modifications you guys would suggest?

hey MrCool,

sikalfex = polyurethane materials, which can at times be very good damping materials. Also its worth mentioning that its pretty easy to improve the damping of a free sheet of most building materials. For example, damping can be measured in "damping factor", kind of like a batting average or a horsepower rating.

the damping factor of drywall as a free panel is ~0.006
plywood is ~0.015
to raise damping to .06 would have a large benefit when tapping a board by hand, and above about damping=0.1 or 0.15, our ears lose their ability to really assess damping and we have to rely on equipment.

but wall performance improves alot above damping of ~0.1, even if a subjective test can't reveal it.

Another consideration is that the damping of something like Green Glue creeps up to its ultimate value over quite a long time, as its designed for damping in its final resting state. the damping of many common materials will peak while they are still wet, and then decline for a long time as they dry thoroughly. plywood isn't as fast-to-dry as drywall, so you might reasonably anticipate several weeks before ultimate properties are revealed.

Finally, in real constructions a rise from .006 to .06 in damping has almost no low-freq effect, and one must indeed instill quite a great deal of damping to generate the large gains that can make damping materials cost effective.

at 5 dollars/tube, sikaflex is still more than GG at the AVS price. :) Considering that and the performance difference, while i don't generally like recommending GG outright, it would be reaosnable to use GG in lieu of sikaflex in your riser, but i do think that your thought of damping the riser is a really good one, and the same for stages and platforms in theaters.

good luck with your construction!

Brian

hey MrCool,
at 5 dollars/tube, sikaflex is still more than GG at the AVS price. :) Considering that and the performance difference, while i don't generally like recommending GG outright, it would be reaosnable to use GG in lieu of sikaflex in your riser, but i do think that your thought of damping the riser is a really good one, and the same for stages and platforms in theaters.

good luck with your construction!

Brian

Brian... if you can overnight me a case of Green Glue at that price I will buy it. A case on the website is 200 bucks. For 12 tubes that is $17/tube.

J

The main difference, I believe, is the 10oz tubes vs the 29 oz Green Glue tubes.

Also at retail pricing the breakdown is under $15 per 29oz tube.


Scott


BTW, I'm still waiting on my order to arrive :)

A case on the website isn't / has never been 200 bucks, its $17_. AVS price is lower @ 160 they are quart tubes, not the smaller tubes.

so 160 / 35 (to equate the volume of material) = $4.60 or so per tube for GG.

overnight freight obviously isn't cheap. :)

take care,

Brian

Pardon my ignorance but how do you get AVS price for Green Glue?

Pardon my ignorance but how do you get AVS price for Green Glue?

Call and ask for it.

Call and ask for it.


Ahh, I see. Thanks.

Or just put 'AVS Forum' as the coupon code

Hats off to Audio Alloy and especially Ted. Great customer service.

background info:

I placed my order last Sunday and after not seeing the UPS truck on Thursday, I emailed Audio Alloy and ask for a update on the ship time. No biggie, I just wanted to know about the approx day of delivery so I could look for the packages. Well the next morning, Ted called me at home to inform me about a computer processing failure that happened with my order. He said that he had sent me an email first thing, but because I hadn't replied so far he wanted to call. In a nutshell he offered to overnight ship my order without any cost to me, if I needed it this weekend. THAT IS GREAT CUSTOMER SERVICE, IMO. Anyway, because I am in no giant hurry, I am having it sent regular ground.

Thanks again Ted and I will look for the boxes this coming week.

Scott (aka Garrett) <----stupid parents and their decision to call me by my middle name :)

Why is it that Audio Alloy's green glue can be talked substantially in effectiveness, cost, where to get it, how to get it, etc. when other products can't be talked about in nearly the same detail without a moderator stepping in? Seems like a double standard. There is marketing, profit and self interests at play which looks to me like its against forum rules.

I understand that there has been a lot of tests run. Why can't Audio Alloy's website of information just stand on its own. If they need thier own forum then start one. I would guess that that without all the promoting from this forum it wouldn't be nearly as successful.

Why is it that Audio Alloy's green glue can be talked substantially in effectiveness, cost, where to get it, how to get it, etc. when other products can't be talked about in nearly the same detail without a moderator stepping in? Seems like a double standard. There is marketing, profit and self interests at play which looks to me like its against forum rules.

I understand that there has been a lot of tests run. Why can't Audio Alloy's website of information just stand on its own. If they need thier own forum then start one. I would guess that that without all the promoting from this forum it wouldn't be nearly as successful.

I think there are a few reasons for this.

1) This is a DIY specialty material not a mass distributed product and offers little conflict of interest for the owners of this forum. Other DIY specialty products are discussed in the same manner like paint mixes, parkland plastics, blackout cloth, liquid nails, etc.

2) GG has a single source - Audio Alloy and Ted has been a member of this forum since I can remember (I've been here since 2000).

3) I could be wrong, but I think AA and GG basically grew up almost as a result of this forum and Ted's participation here.

4) If you look closely, it is the members, not the principals that are hyping this stuff. I cannot ever recall Brian or Ted (who rarely speaks on the issue) ever doing anything other than going out of their way to not seem like they are selling their product here. Look in the speaker forum and you will find 10x this many people hyping Ascend speakers or SVS subs. These forums are excellent marketing tools for these ID companies and they work the best when its the customer doing the marketing.

So, while it may appear that there is a double standard and, in fact, to some small extent there may be I think the above reasons explain some of it. The owners of this forum get to say what does and does not go on here so they may have to step in at some point. Or, they may choose not to.

Grant:

Sika makes excellent products some of which have been specifically formulated to address specific issues in the automotive industry. This does not mean some of these formulations would not prove to be effective as a CLD material for the very specific applications being discussed in this forum.

Audio Alloy has formulated and tested (and tested, and tested, and tested) a product specific to CLD applications and specific to architectural acoustics applications. I know of one other such product. Based upon independent laboratory testing the Audio Alloy product is the superior performer. When purple goop is invented and is equally safe to use and provides better performance, you'll find all the discussion heading toward the purple goop camp.

I'd also have to suggest that Brian's contribution to this industry by virtue his considerable research and testing (in certified labs at his expense) into sound isolation techniques, wall and floor construction methods, flanking and similar areas has been stunning and only exceeded by his willingness to share that information in as neutral and as unbiased as one would expect from a true scientist.

By the same token, I don't believe anyone here is discouraging discussion of alternative products or methods...Brian included. Rather, as is common in other threads, there is an effort by those who've "been there, done that" to caution others about repeating the errors or mistakes of others.

Dennis,
With all the glowing endorsements and quick defense you give for GG and Audio Alloy you sure give the appearance of someone that benefits from thier success.

Do you go to such extremes to endorse any of the other many products you routinely use? If so what are they? This would be a great sticky to have as long as we are trying to help people pick the best products and reduce costly errors.

Please do not interpret this to mean that I question your judgement on products - I have no doubt that you have researched every product you use to the nth degree.

Grant

ummm... you are in the "Green Glue" thread, it stands to reason that the majority of the post will be about the product. Since it has been proven time and time again that this stuff does what it claims (by the individual users and the scientific test), why wouldnt the majority of the post be a recommendation of GG????

Hey no offence to Brian, but most of his techno babble goes way over my head. I did research and read what the DIY users' experiences were and also what DE had to say on the issue. After all building these HT's is his business.

As far as Dennis' product list..... have you not been reading the dedicated forum? I have for a very long time and I personally trust his opinion. He chimes in all the time on his choices for the ingredients for our HT's.

I dont see why you are fighting the use of a proven product. BTW in sound isolation... 2-3 dB reduction in the sub freq is a noticable difference.


Scott

...and for the record, I do not benefit in any manner from the sale of Green Glue nor am I associated with the company in any manner other than as a paying customer. I utilize their product and other products from various other vendors in my Sound Isolation classes.

I think, Grant, you'll find I also reference, frequently, Acoustik Mat, PAC-Intl RSIC Clips, and various products from Zero International. These products are easily available, reasonably priced and do exactly what the manufacturer says they'll do *AND* they have all be subjected to tested by independent certified labs.

I also look at the products we use and specify from a different light than perhaps you do. You use the product and it doesn't perform...oh drats. I specify the product or utilize it in one of our construction projects and it doesn't perform, I can get sued.

I have to make a sacrifice in the design of my new home theater. I would love to sound proof the ceiling as much as possible but at the same time the ceiling is only 7 feet and I really dont want to use a hat channel if I can get away with it. How much dampening do you I think I would lose using only double drywall with green glue as opposed to using RSIC- hat channel-Dry wall-green glue-dry wall ??

I have to make a sacrifice in the design of my new home theater. I would love to sound proof the ceiling as much as possible but at the same time the ceiling is only 7 feet and I really dont want to use a hat channel if I can get away with it. How much dampening do you I think I would lose using only double drywall with green glue as opposed to using RSIC- hat channel-Dry wall-green glue-dry wall ??
First of all, I'd be surprised if the vast majority of people building their HTs don't have to make some compromise. Seems to be the nature of the game.

I faced a similar problem, only my ceilings were less than 7' - more like 81". I described what I did in this post: http://www.avsforum.com/avs-vb/showthread.php?p=6940219&highlight=bob+md#post6940219

I've very please with the results, although hanging RSIC clips in this manner was a bit time consuming. If I had to do it again I'd do it the same way. There's next to no sound transference between my floors and I have a bathroom right above the HT. The only thing I hear is a footfall on my wood floors if someone has hard-soled shoes.

If I couldn't do hat channel, I'd definitely do the GG. If I could only do one or the other, I'd do GG. But like I said, I'd do both, there's enough room if you follow the above technique.

Good luck!
Bob

Be wary of basement code - in my area code is 7'. If you are doing an extensive remodel - they can force you to follow current code - even if your basement was built a long time ago and should be grandfathered. In my basement carpet to ceiling it is exactly 7' - but opening up the ceiling I see the plaster is on a bit thick - plus lots of shims. Still it will be a choice of ceiling vs. floor and using the special clips to just make 7'.

Be wary of basement code - in my area code is 7'. If you are doing an extensive remodel - they can force you to follow current code - even if your basement was built a long time ago and should be grandfathered. In my basement carpet to ceiling it is exactly 7' - but opening up the ceiling I see the plaster is on a bit thick - plus lots of shims. Still it will be a choice of ceiling vs. floor and using the special clips to just make 7'.
I hear you on that. In my county, code is ceiling height of 6'8" for older homes. By the time I did DriCore, 2 layers of drywall & recessed RSIC clips, I was just over 6'8". My bigger problem was the same height restrictions are for stairs. I had a joist right over the bottom step that I had to do some creative work with.

Well there is no way that I can use RSIC clips and Double dry wall and keep it 7'. I am about 6'9 myself so I cant stand to spare an inch. Do you think that just the combination of double dry-wall and green glue will be enough to knock it down 30 or 40 decibels ??

Uugh stairs I don't even want to think about - hit my head on the joists of the attic stairs everytime I go into the basement office. For sure it is not current code - and if I build an HT wall alongside the stairs they will likely insist the stairs must be brought up to code. I entertain fantasies of flooring the stairwell - turning it into a kitchen pantry - ripping out the stairs for more HT space - and digging up the kitchen porch and cutting thru the basement foundation wall for a nice exterior exit. Imagine the "honey I could not hear you I was working 'outside' in the basement" possibility!

Petrucci
Maybe you can add some mass/damping to the subfloor above from below with GG/DD?

D.E. wrote (I also look at the products we use and specify from a different light than perhaps you do. You use the product and it doesn't perform...oh drats. I specify the product or utilize it in one of our construction projects and it doesn't perform, I can get sued. )

Excellant point - I wasn't thinking along those terms. With large projects and lots of money on the line I'm sure this is very real in today's world. When I compromise all I have to worry is about how much complaining my wife will make. Usually that complaining is more about the money spent vs. performance. I guess that is the main reason why I was trying to understand at what performance gain can a DIY person can justify doubling the cost of sound isolation.

I understand why you have to go 100% for clients - they aren't going to be happy making those compromises. If I had the money to spend on a D.E. theater I would expect the best also.

Grant

HI. I have ordered 48 tubes of green glue a few months ago. Tonight I just started using it for the first time. I was anxious about how hard it would be to use it. Well, let me tell you I am happily surprised!

For your information, I have been caulking the perimeter of my first layer of drywall with LEPAGE acoustical sealant. This is a butyl based sealant. Compared to this, regular silicon sealant smells nothing and is NOT sticky!

Well, applying Green glue is VERY easy compared to using the Acoustical Sealant I chose (36 large tubes of it). Green Glue smells almost nothing and is a LOT easier to clean up versus the acoustical sealant....


More impression as the product dries up...

More impression as the product dries up... Cool. We'll look for your report in about 2056 then. ;)

Looking for an opinion from Brian and anybody else who cares to chime in....

I'm converting my downstairs, which connects to the rest of the house though an open stairwell, into a home theater / recording studio. I have decided not to rip out the existing 1/2" drywall (which has the typical splatter texture on it) and I am adding new walls to close off the openings to the rest of the house. I am building the new walls with 1/2" drywall to match the existing construction before I add more drywall to the interior of the room I am trying to isolate.

Because of concerns that the existing texture could impact the performance of the GG and because my new unfinished drywall is slightly thinner than the existing textured surface, and because I'm thinking I will benefit from the extra mass, I am considering adding a new layer of 5/8" drywall, then GG, then another 5/8" drywall, all on the interior of the room.

The other option I have considered is to add just one layer of 5/8" with Green Glue. That would obviously be a lot easier. Any thought on the costs/benefits of these options? I'm trying to determine if I'm going to get any significant improvement in exchange for the extra effort.

Thanks,

Tim

Hi Tim,

How textured is that wall? Generally walls aren't too textured, and can be Greened over effectively. Too textured = pointy = painful, so that texture is usually reserved for ceilings.

Hi, Ted-

It's pretty flat. Looks like the texture was applied and then smoothed over with a big trowel.

Tim

Hi Tim,

Well, I'd say you'd have no real issues, then.

HI. I have ordered 48 tubes of green glue a few months ago. Tonight I just started using it for the first time. I was anxious about how hard it would be to use it. Well, let me tell you I am happily surprised!

For your information, I have been caulking the perimeter of my first layer of drywall with LEPAGE acoustical sealant. This is a butyl based sealant. Compared to this, regular silicon sealant smells nothing and is NOT sticky!

Well, applying Green glue is VERY easy compared to using the Acoustical Sealant I chose (36 large tubes of it). Green Glue smells almost nothing and is a LOT easier to clean up versus the acoustical sealant....


More impression as the product dries up...

Good luck with it all stef2, or, rather, i hope it all works out.


And on a side note, i've been on a bit of a vacation, which seems to have done the mind some good. Instead of delerious and looney, i'm looney yet peppy.



Cool. We'll look for your report in about 2056 then.

That was pretty darn funny!


And on another side note, none of the fellas that frequent this forum are affiliated with GG outside of the obvious, nor do they profit from its sale.

I will offer that i don't think any of the professionals from this forum ever condoned the use of GG without extensive 3rd party test data or personal hands-on testing. They're kind of tough that way, but as DE & others mentioned, that's their job.

I'm near complete with the Green Glue and also agree very easy to apply, not much of an odor, no mess if your careful. :D

Being the cheap skate I am I did re-use the same nozzle on each application day.....those nozzles are big so thought I'd get a 2% increase in coverage by reusing :eek:

I ordered a bunch of GG and soon I will be ready to use it.....I'm living in France and just realized that the GG tubes are huge. Tubes here in France are of a smaller kind and the "gun" also...

I'll do some searches to try to find a bigger one but could you guys recommend an online source for the gun.


Cheers,

Exipnos

The drywall glued with liquid nails had no discerable differences to non-glued (just stacked) drywall pieces. I'm certain we could have measured differences but that was not the point of the exercise. Liquid Nails (construction adhesive) would not be considered a dampening agent in any case.

I can see why Liquid Nails wouldn't offer any damping because when it dries it dries hard. How would something like silicone adhesive do since it dries and remains rubbery vs. green glue?

exipnos, there are usually two types of caulking gun. The smaller one you are used to and the larger size which is more a pro/contractor size. You should be able to get either at any good home improvement store.

fsrenduro, I think you will find that question has been answered many times in this exact thread.

Andy K.

I'm near complete with the Green Glue and also agree very easy to apply, not much of an odor, no mess if your careful. :D

Being the cheap skate I am I did re-use the same nozzle on each application day.....those nozzles are big so thought I'd get a 2% increase in coverage by reusing :eek:

re-use nozzle?

doesn't each tube have its own nozzle like a regular tube of caulk?

You'll need a '29oz Caulk Gun' - do a search and you will find loads of online site - not sure how many will ship internationally

Here are some

http://www.westerntool.com/product.htm?pid=455924
http://www.dhcsupplies.com/aaadhesives/adh1.tools.htm

re-use nozzle?

doesn't each tube have its own nozzle like a regular tube of caulk?

No, the GG tubes have a screw on nozzle.....and wouldn't be surprized if that hold 1oz of GG so by re-using you save 1oz per tube.

Have yet to place my GG order, but at two tubes per 4x8 sheet, is hand fatigue a factor? Some have written than GG is a lower viscosity than typical caulk, but is it that big of a difference? I thought I've seen battery operated guns before, but maybe not for the larger tubes.

I'm not doing the work, but I can already hear the construction crew complain about the extra work (although I will be paying for the extra labor...)

Believe me you will not get hand fatigue - on the caulk gun I used (basic model from Big Orange) I needed very little pressure.

I have used several systems within the walls of my theater, as well as sound shaping systems on top of them. Within the walls are clips and channels to suspend the walls and the ceiling, heavy duty insulation throughout, rubber matting to dampen sound in critical areas, a layer of plywood and two layers of drywall with Green in between them.

I can say that during the construction process the single greatest change in the sound of the room is when the Green Glue was put in. The room immediately became very neutral and dead, and the sound stayed in the room. We did different tests at all stages as controlling the sound was extremely important as the room is flanked by stairways leading up, and the cavity under the stairs is adjacent to the room on both sides.

However, remember, sound is like water - it will find a way if you give it one. You can not do this partially and expect any real change in the sound. If you leave a panel untreated, that is where the sound will leak out. If you do not do the ceiling, then why bother - the sound will travel upwards.

Green Glue does what it says it will do, and what it does is amazing. However, you need to plan your room carefully. Drop ceilings are right out. Poor wall construction is a nightmare waiting to happen. Think this through. You will generally only have once chance on getting this right. The Green Glue is an excellent product that I am sure you will feel as strongly about as I do once you get it in the walls.

Maybe I am beating a dead horse and I didn't read through this whole thread
Question,
I am planning an HT room in the basement. It sound like I need to double drywall if I want to do this correctly. However, I do need to do a drop ceiling in the rool due to shutoff valves, etc. Will GG be a wast of time for that room?

Gondey,

A dropped ceiling (armstrong, etc) won't help much at all with isolation, and would be such a weak point that it probably means you should save your efforts on the walls.

However, I would imagine you have no more than 2 or 3 valves, and you may want to consider having simple access panels in a drywall ceiling. That's been done quite a bit.

[QUOTE=eskay]Have yet to place my GG order, but at two tubes per 4x8 sheet, is hand fatigue a factor? Some have written than GG is a lower viscosity than typical caulk, but is it that big of a difference? I thought I've seen battery operated guns before, but maybe not for the larger tubes. QUOTE]


Green glue is very easy to apply. To me the viscosity of GG seems to be lower than regular caulk. ON the contrary, the slightest pressure will make it come out of the tube (sometimes maybe too easily...)

I ordered a bunch of GG and soon I will be ready to use it.....I'm living in France and just realized that the GG tubes are huge. Tubes here in France are of a smaller kind and the "gun" also...

I'll do some searches to try to find a bigger one but could you guys recommend an online source for the gun.


Cheers,

Exipnos

Expinos,

did you get the caulk gun matter resolved? it might be possible to ship one over there

Brian

I can see why Liquid Nails wouldn't offer any damping because when it dries it dries hard. How would something like silicone adhesive do since it dries and remains rubbery vs. green glue?

Its not just that something doesn't turn hard, it also has to have energy-dissipating properties.


Imagine a superball and a ball of peanut butter. One would bounce, one would just splat and make a mess. The superball stores the energy, the peanut butter dissipates it (the kinetic energy from the fall spreads/moves the peanut butter, and the peanut butter doesn't bounce back, the energy squishes the superball, but teh superball bounces back)

Silicone is like the superball, it bounces. Damping materials are sort of like a hybrid cross of the superball and the peanut butter. they don't just splat, but they don't bounce.

The superball properties make them non-liquid, because liquids are useless as they dry, flow, soak, etc.

the peanut butter properties make them useful for vibration and sound applications, as they dissipate energy when moved and bent and stretched.

???

so you are saying that you can save the money for green glue and apply peanut butter instead? :p :D

so you are saying that you can save the money for green glue and apply peanut butter instead? :p :D

:D :D

i'm convinced that, for at least a day or two until it dried out, if you could determine the proper film thickness peanut butter would prove at least somewhat useful as a damping material.

its not stiff enough or dilatent enough to really be ideal, but i swear it would do something. :p

i'm glad you guys are having an easy go of tube squeezing, we've spent huge amounts of time trying to make the squeezing easier w/o having the stuff run off the board.

:)

Bryan - you did a great job. In most areas the drywall was flat on a lift or on the floor when applying the GG. But in one area I had to lean the drywall at 60deg and there was no running.

Just need to wait and see if it lives up to its reputation now. ;)

:D :D

i'm convinced that, for at least a day or two until it dried out, if you could determine the proper film thickness peanut butter would prove at least somewhat useful as a damping material.

its not stiff enough or dilatent enough to really be ideal, but i swear it would do something. :p
Draw ants to your theater?? ;)

Received my 5 cases of Green Glue yesterday. Just about every tube had some Green Glue coming out around the bottom cap. Is this normal? On the tubes that did not have this problem, the end cap was actually sitting a bit above the tube instead of being recessed a fraction of an inch like the rest.

Also, I won't be at the drywall stage in my construction for at least a few more weeks. Should I store the tubes upside down (nozzle end down) to prevent any more Green Glue from oozing out?

Hi Rich,

A small amount of dried Green Glue on the bottoms of the cartridges is perfectly normal. This won't affect its use or application at all.

This occurs during the actual filling of the cartridges. The Green Glue isn't oozing out, and can be stored for months in any orientation.

Please keep in mind that "dry" Green Glue is very sticky and soft and often misinterpreted as "wet".

Draw ants to your theater?? ;)

:D :D :D

Expinos,

did you get the caulk gun matter resolved? it might be possible to ship one over there

Brian

No I didn't. I went to several professional building supply stores and even though I found a larger size it was way to small to fit the GG cartridge. I showed them the cartridge and they claim nothing exists over here to handle that size!

I just emailed Ted about a gun. Let me know if I should try a online store instead...

Thanks

Exipnos

If you are going ship one to europe, don't have it listed as a "Caulking Gun" on any of the paperwork. Try "caulk dispenser". I suspect any mention of "gun" in the description will just slow things down.

I could be wrong, but all customs and shipping people are probably not up on home improvement tool terminology.

Question for the GG experts (Brian or Ted):

I have an existing theater room upstairs with 2 of the walls external. Can I get away with double drywall + GG on the 2 internal walls and double plywood + GG on the subfloor and still get good isolation (assuming other paths are treated - doors, vents, etc...)? Trying to minimize rework since the room is already finished out.....

thanks in advance,
ed

If you are going ship one to europe, don't have it listed as a "Caulking Gun" on any of the paperwork. Try "caulk dispenser". I suspect any mention of "gun" in the description will just slow things down.

I could be wrong, but all customs and shipping people are probably not up on home improvement tool terminology.

Try 'Sealant Dispenser' as I doubt most in Europe will know what caulk is. :D

If you are going ship one to europe, don't have it listed as a "Caulking Gun" on any of the paperwork. Try "caulk dispenser". I suspect any mention of "gun" in the description will just slow things down.

I could be wrong, but all customs and shipping people are probably not up on home improvement tool terminology.

interesting thought.

I used GG in my basement theater last year (back when it was sold in 5 gal. pails) and I was and am extremely happy with the results and the fine folks at Audio Alloy. Based on my recommendation, a friend used GG for his basement (not a theater) with good results as well. However he has several tubes left over. Is there a place on this forum to sell left over stuff?

AVS classifieds for members only....

http://www.avsforum.com/avs-vb/forumdisplay.php?f=123

I know I've read this before, but I couldn't find the answer to my question: I'm almost finished with putting up the second layer of drywall in my HT. How long does it take for Green Glue to be fully effective? A few hours, days or weeks? I'm just being curious about what to expect as time goes by...

I know I've read this before, but I couldn't find the answer to my question: I'm almost finished with putting up the second layer of drywall in my HT. How long does it take for Green Glue to be fully effective? A few hours, days or weeks? I'm just being curious about what to expect as time goes by...Give it a couple of weeks. I think I've read that it takes about 30 days to reach the majority of its potential.

(Another way to put it.... its effectiveness is the inverse of that wonderful smell you experience when it is applied. As the smell dissipates, the effectiveness increases. :D )

Is there still any discount on this stuff? and do you have to be a paid member of AVS to get said discount? if not, how does one get the discount applied?
thanks.

You have a PM

Ted,

Can you give me some idea of what kind of difference I might find using two layers of 1/2" drywall with greenglue as apposed to a layer of 1/2" and a layer 5/8" with green glue ??

Thanks,
Eric

Hi Eric,

In such a situation, go for the mass. Two sheets of 5/8". Or three 1/2" and 50% coverage of Green in between. More mass in such a system will se an improvement across the frequency spectrum, but you'll see the greatest value in the low frequencies!

I'm considering GG but am wondering if anyone has provided information previously on:

1. What and whether it off-gases while curing?

2. How long it has to cure before it's done off-gassing and is inert?

3. When it burns, and I know it's almost a fire retardant, does it produce toxic byproducts?

4. Anything else a potential customer with young kids and a tendency to avoid ecologically unfriendly stuff should know?

If this has been covered previously and I missed it, feel free to point me to the posts.

Thanks,

-scott

Ted - I'm starting construction on a new, one-level brick home with concrete slab and I'm not sure to what level I need to soundproof my room. I'm a novice at this but have reviewed your site and feel like I'm starting to get a handle on some of this. My builder is not planning anything other than R-11 batts in my 2x4 walls surrounding the Theater Room at this point . After researching this, I'm feeling this is inadequate given my SVS PB-12/plus 2 subwoofer plans in the future. :)

What is your recommendations regarding each wall and ceiling for maximized return with minimal budget? I really don't want to spend more than $2000 more in addition to what is already budgeted so I'm hoping you can help me pinpoint where I need to target and how to accomplish this - things like GG, staggered stud walls, etc. I've numbered the walls for ease of discussion. I'm hoping walls 2 & 3 can be minimally treated and walls 1 & 4 w/ ceiling will get additional help. Suggestions are appreciated.

http://members.cox.net/jbratton/Theater_Room.jpg

I'm considering GG but am wondering if anyone has provided information previously on:

1. What and whether it off-gases while curing?

2. How long it has to cure before it's done off-gassing and is inert?

3. When it burns, and I know it's almost a fire retardant, does it produce toxic byproducts?

4. Anything else a potential customer with young kids and a tendency to avoid ecologically unfriendly stuff should know?

If this has been covered previously and I missed it, feel free to point me to the posts.

Thanks,

-scott

hey guys, i hope everyone is well. Ted asked me to reply to this query, so to answer

1. Like every latex product, Green Glue has water and a bit of ammonia that evaporates into the air, but off-gassing in a health-concern or significant way, no, it doesn't.


2. It depends on some factors, like ambient humidity and temperature, what materials its between, etc. (wood dries slower than drywall). Damping properties develop within 24 hours, and approach their final values within 1-2 weeks. With respect to toxicity, there is no window at all during which it is dangerous. Some slight odor may be present and how long it lingers depends on the factors above. A big effort was made some months back to drive the odor level to a bare minimum, and i think the result was basically no more comments from customers about odor, Ted could confirm that.


3. Any polymer can generate toxic products during combustion, including carbon monoxide and so forth. But Green Glue does not generate any peculiar or particularily concerning by products during combustion, as its components are basically similar all latex products. Green Glue is an acrylic material, and while i'm not really at liberty to discuss the particulars, the combustion products of most acrylic materials are similar, even though the word "acrylic" spans a huge range of different polymers.

It is never adviseable to expose yourself to smoke, and should a fire involving green glue occur, avoiding smoke is just as good of an idea as it would be with normal paint or whatever on the walls. The combustion products of Green Glue should be essentially the same as those generated from combustion involving paint.



4. One of the big goals during R&D for Green Glue was to achieve a VOC level as close to zero as is possible. No product (no latex product anyway)c an ever truly be zero VOC, but Green Glue comes awfully close. It qualifies for green building standards and so forth. It is far, far lower than the strictest VOC standards in the nation.



The toxicity of Green Glue is in line with or less than typical latex paints, but it is nonetheless our advice that you minimize contact with skin, accidental ingestion and so forth. That same advice will generally serve you well when handling almost any chemical that households may contain.

hope that helped.

Brian

Just found a small blob of GG on carpet - Somehow I manage to keep the whole of the concrete floor in the HT spotless but somehow some got on carpet that was covered with duist sheet :(

Its been there at least 6 weeks - any suggestions for cleaning?

I used GG in my basement theater last year (back when it was sold in 5 gal. pails) and I was and am extremely happy with the results and the fine folks at Audio Alloy. Based on my recommendation, a friend used GG for his basement (not a theater) with good results as well. However he has several tubes left over. Is there a place on this forum to sell left over stuff?

http://www.avsforum.com/avs-vb/forumdisplay.php?f=123

Mako,

If you want to hold in the low frequencies of those subs, you'll want to deploy as many elements from your "tool bag" as possible / practical / economical.

#1 Framing. We'd prefer to reduce the amount of vibration that gets into the framing (studs and joists). Once the vibration is in the framing, it can travel like the string between to juice cans. Get some de-coupling in the room. The room is over the garage, right?

Build a new set of studs inside the existing room (double studs) or modify the existing walls into staggered. See here: http://www.greengluecompany.com/wallTypes.php

For the floor consider adding a second sheet of OSB and damp it.


For the ceiling, since there's no living space above, consider installing inexpensive wood furring strips to the underside of those trusses. Every 24", perpendicular to the trusses. Make sure to pre-drill the strips, use construction adhesive between the furring and the truss, and use a wood screw or deck screw (not a drywall screw)

#2 Get some insulation in the walls for absorption.

#3 Add mass. Double drywall is recommended, damped is better. If you are considering a material like Green Glue, you might consider using 1 tube per sheet on walls 2 & 3. 2 tubes on the ceiling and floor and walls 1&4.

Mako,

If you want to hold in the low frequencies of those subs, you'll want to deploy as many elements from your "tool bag" as possible / practical / economical.

#1 Framing. We'd prefer to reduce the amount of vibration that gets into the framing (studs and joists). Once the vibration is in the framing, it can travel like the string between to juice cans. Get some de-coupling in the room. The room is over the garage, right?

Actually the room is beside the garage - the garage is a 3 car and is next to wall 3.


Build a new set of studs inside the existing room (double studs) or modify the existing walls into staggered. See here: http://www.greengluecompany.com/wallTypes.php

I'm considering a staggered stud design but am trying to save as much room in the interior of the theater as possible. Would a staggered stud for walls 1 & 4 and standard studs on 2 & 3 work or will the sound travel through that framework into the house - even though they are "outside" facing walls?

For the floor consider adding a second sheet of OSB and damp it.


The house is going to be built on a concrete slab with no subfloor. So are you suggesting that I put OSB on the concrete or would this only apply to wood subfloors?

For the ceiling, since there's no living space above, consider installing inexpensive wood furring strips to the underside of those trusses. Every 24", perpendicular to the trusses. Make sure to pre-drill the strips, use construction adhesive between the furring and the truss, and use a wood screw or deck screw (not a drywall screw)

Got it. I think I can explain this one to the builder and shouldn't be an issue - might be a little more trouble but inexpensive to do.

#2 Get some insulation in the walls for absorption.

Do you think the R11 bats are sufficient?

#3 Add mass. Double drywall is recommended, damped is better. If you are considering a material like Green Glue, you might consider using 1 tube per sheet on walls 2 & 3. 2 tubes on the ceiling and floor and walls 1&4.

Definitely considering GG - heard nothing but praise for the product. I was planning on doing double dry wall on the interior walls but single dry wall on the exterior. Do you think that would be sufficient? I'll follow your recommendations for 2 tubes for ceiling, wall 1 & 4 - and 1 tube for wall 2 & 3. I was kinda hoping not to even have to do wall 2 & 3 but I think that was wishful thinking.


Thanks again for all your help - any other suggestions from you or others is appreciated.

Mako,

Staggering the walls as per that link earlier will sacrifice 1" on the wall. The new studs are placed every 24", so not much effort or costs. The 2x4 bottom plate becomes a 2x5. Alternately, since this is new construction, you could rip a 2x6 to 2x6.

Because the structure (original studs and joists can condust effectively (a bad thing) you would do well to decouple all the walls.

If the floor is a slab (not above garage as I incorrectly thought) then leave the slab alone. You could treat it, but that's not your weak link.

R11 in walls is great.

Thanks!

Just found a small blob of GG on carpet - Somehow I manage to keep the whole of the concrete floor in the HT spotless but somehow some got on carpet that was covered with duist sheet :(

Its been there at least 6 weeks - any suggestions for cleaning?If your wife or S.O. knows an Avon Lady, have her get some Avon Skin-so-soft bath oil. I know it sounds odd, but it is by far the best stuff I've found for removing GreenGlue.

London,

Try applying baking flour to "monopolize" the stickiness of the Green. Then roll off as much as you can with your thumb into a small ball. After that, any other cleaners used (Avon, Goof-Off, Goo-Gone, citrus types) should be testd in some unseen area of the carpet to make sure they don't remove the color, etc.

Mako,

Staggering the walls as per that link earlier will sacrifice 1" on the wall. The new studs are placed every 24", so not much effort or costs. The 2x4 bottom plate becomes a 2x5. Alternately, since this is new construction, you could rip a 2x6 to 2x6.

Because the structure (original studs and joists can condust effectively (a bad thing) you would do well to decouple all the walls.

If the floor is a slab (not above garage as I incorrectly thought) then leave the slab alone. You could treat it, but that's not your weak link.

R11 in walls is great.

Thanks!

Ted - Thanks, appreciate the input. So do you think I am safe with just doing the interior walls of the theater or will the exterior walls (both sides of walls 1,4, &3 need to be done with the GG/drywall combo?

I'll definitely do the staggered stud for the entire room - for some reason I had it in my head that it took up more space than that. Obviously hadn't thought that through...

Hey folks,

i would like to add a little bit to the question i replied to above.

First, no latex can ever be honestly called zero VOC. The reason for that is that there is always some PPM level of residual mateirals that would be classified as VOC after the reactions that form the latex are completed. "zero-VOC" is more marketing chit-chat than reality, and the VOC reported on the MSDS for GG reflects residuals as best it can.

Second, materials like ammonia or ethanol amine or triethylamine or AMP are used in basically 100% of latex materials, be they paint or caulk or Green Glue or whatever else. The reason that they are used relates to emulsifying the polymers into water. They are present in an extremely low level. For example, in Green Glue ammonia is present at <0.05%, a level sufficiently low to not have to be reported at all as such low levels have been deemed to be a non-issue by higher and more knowledgeable authorities. But our basic policy is to be as open with information as possible. It doesn't mean that Benjamin Moore is being sneaky if they don't report such a substance (one is present), they just opted not to. Finally, the ammonia or amine of some kind associates with acid groups in the latex, and doesn't rush out of the film all at once.

The same basic safety principles can reasonably liberally be extended to most latex products. You should strive to minimize ingestion, inhalation, and skin contact.

Just finished reading this entire thread!!! Lots of good info. I do have a question about the basics (mass, absorbtion, flanking, etc). What about re-directing the sound energy instead of trying to meet it head on?

For example: take a standard 2x4 wall that has green glue (or what ever to make a good seal) on the edges of the studs before putting up the drywall on both sides (with or without insulation and ignoring additinoal layers for now). Now the air inside is 'trapped' inside the wall cavity and more likely to act like a spring, and hence more likely to transmit the sound energy from one side of the drywall to the other.

In my situation, my HT will be comleterly over a finished garage. I was thinking 'what if' I drilled one or two 1" holes in the base plate into the joist spaces of the garage below? I don't care what the car hears. It's all 2x6 insullated 5/8 drywall on the walls and ceiling with a concrete floor.

That or drilling holes thru the 2x4 studs to redistribute the energy along the length of the wall (assuming sections of the wall closer to the sound source are going to vibrate more than farther sections).

Now I don't know if it is to code (and probably won't go thru the trouble to do it anyways) but decided to wonder outloud if something like this would have an effect.

You should strive to minimize ingestion

But... But... Green Glue is so tasty! :D

Just finished reading this entire thread!!! Lots of good info. I do have a question about the basics (mass, absorbtion, flanking, etc). What about re-directing the sound energy instead of trying to meet it head on?

For example: take a standard 2x4 wall that has green glue (or what ever to make a good seal) on the edges of the studs before putting up the drywall on both sides (with or without insulation and ignoring additinoal layers for now). Now the air inside is 'trapped' inside the wall cavity and more likely to act like a spring, and hence more likely to transmit the sound energy from one side of the drywall to the other.

In my situation, my HT will be comleterly over a finished garage. I was thinking 'what if' I drilled one or two 1" holes in the base plate into the joist spaces of the garage below? I don't care what the car hears. It's all 2x6 insullated 5/8 drywall on the walls and ceiling with a concrete floor.

That or drilling holes thru the 2x4 studs to redistribute the energy along the length of the wall (assuming sections of the wall closer to the sound source are going to vibrate more than farther sections).

Now I don't know if it is to code (and probably won't go thru the trouble to do it anyways) but decided to wonder outloud if something like this would have an effect.

your idea is very good, and i've had a similar thought. basically, can i eliminate the low frequency resonance (or at least help tame it) by opening up the wall somehow. And i've taken the liberty of testing it in a 3rd party lab... and

the thing is that even if you un-seal one side of the wall, the spring force of the air cavity is practically unchanged. The reason for that is that the air can't readily flow in and out of the small crack at a high rate. I have tested this in a lab, and can post the data if you or anybody desires. Even at the frequencies where the air spring causes the most trouble, unsealing one side hurts performance and doesn't help.

attached pic illustrates. In the graph, note the low-frequency dip... it doesn't get any better from the venting, and surrounding frequencies get worse depending on how much venting you apply.

Its a really good idea, the basic physics just don't let it happen at the endo f the day.

But... But... Green Glue is so tasty! :D

:D :D :D

i think years of lab work make me a bit more cautious than most people about things. for example, propylene glycol is common in latex paints... but i wouldn't open a jar w/o gloves and ventilation.

But, tts FDA approved for use in food and i just ate some on the gift bag of flavored popcorn sitting on my desk.

oh, the irony

You would be amazed at how many food products have propylene glycol in them.... (not to mention windshield wiper fluid!)