Is Green Glue available for sale yet anywhere? I'm almost to the drywalling stage for my home theater. Thanks much.

Alan is posting a Power buy on Green Glue this evening.

Originally posted by Ted White
Alan is posting a Power buy on Green Glue this evening.

Great!

Here you are:

http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=456810

Those are some pretty impressive plots Ted. Looks like a great product.

Good Luck!

Thank you and I won't call you Shirley.

Ted,

I am in the process of building a HT.
I am doing room within a room and don't know if I would benefit from this product enough to make it worth while but I along with everyone else would like to know more.


Craig :)

The product is worth it even for room within room type of construction.

We've not only used the product; but, have a pretty interesting demo in the store.

We have a transducer ... one of those items designed to be attached to a wall or ceiling to create a PA or background music source. We place the transducer on our 4' x 22' x 3cm marble counter top. We get music (rather loud at that). We then place two pieces of 5/8" stacked drywall on the counter and the transducer on the stack. Still get loud music. We then lay two 5/8" pieces on the counter (laminated with green glue between them). No sound. No music. Technically, this is impact noise, but the demonstration effectively illustrates dampening.

Can Green Glue only be used between two sheets of drywall?

No...
"two sheets of _______ " fill in the blank.

This is one of those rare times that my lack of ambition has paid off. I have been on the framing portion of my "DE" designed theater for some time now. The original plan was to decouple the room from the rest of the house using the RSIC clips and hat channel. The Green Glue product has come out and, after many e-mails back and forth with Ted White and one with Dennis to get the wink and nod, I will be using the Green Glue rather than the RSIC/hat channel.

It is not cheap but the power buy helps greatly and I have all assurances that I will be thrilled with the results of the treatment. I am building a room that is 14'x9'x26'. You start adding up the sq feet involved in walls ceiling, stage, riser :eek: the numbers get big. I will get the added benefit of getting a bit of interior room back, as I am using dual 5/8 rock (Green Glue between) rather than the clips, channel, and 1/2 over 5/8 (clips remove a bit over 1 3/4 of interior space per side). I was tight in my isles so every inch counts!

I am even considering using this product in my office/guitar/hide from the world/spare bed room room, along side the theater.

At 50.00 off a 5 gallon order, there is money to be saved. I am very hopeful that I can be one of the testimonials of how stellar this product is, in the very near future.

Now I have to get off my butt adn start working on the basement again!

I was in a pinch so Ted let me pre order some. Let me just say that Audio Alloy has great customer service. Ted was very informative through the whole order/questions process, let me purchase some ahead of time, and he said it would arrive Tuesday. Bam, I got home tonight (Tuesday) and it's sitting on the doorstep!

Can't attest to the actual sound proofing characteristics yet but the company certainly seems top notch!

I have a quick question for Ted. What is the best way to utilize this product over a plywood subfloor on the first floor? Similar, to the acoustimat with 3/4" t&g plywood. Replacing the acoustimat with green glue or some other method. Possibly two thinner layers of plywood with green glue between each layer. How thick a layer does one apply of the green glue?

Thanks for any info

Originally posted by E. Martin
This is one of those rare times that my lack of ambition has paid off. I have been on the framing portion of my "DE" designed theater for some time now. The original plan was to decouple the room from the rest of the house using the RSIC clips and hat channel. The Green Glue product has come out and, after many e-mails back and forth with Ted White and one with Dennis to get the wink and nod, I will be using the Green Glue rather than the RSIC/hat channel.

Wow! The product is that good? I would love to save the ceiling height when I drywall by forgoing RSIC and hat channel, even if it costs a little bit more for the GG. I certainly cannot afford both as I will need at least 2 5-gallon buckets of GG to complete the ceiling and the walls.

Dennis, are they really that comparable in sound absorbing quality (assuming 2x 5/8 drywall connected drywall->GG->drywall->GG->joist)? Or would I not want to use GG between the inner sheet of drywall and the ceiling joists (and/or stud wall)?

Justin...use the Green Glue.

Audio Alloy's Green Glue is a Design Cinema Privee "Approved Product".

I am in the planning stage of my home theater and I have read many posts regarding Green Glue. I am interested to learn more about the product. Are the manufacturer's installation instructions available to view?

Ted, I am over near you from time to time. Is the product available to be picked up as opposed to being shipped?

Mark

Originally posted by Dennis Erskine
Justin...use the Green Glue.

Audio Alloy's Green Glue is a Design Cinema Privee "Approved Product".

Thanks Dennis.

Just to confirm, GG would go between the drywall and stud/joist as well?

We've not only used the product; but, have a pretty interesting demo in the store.

We have a transducer ... one of those items designed to be attached to a wall or ceiling to create a PA or background music source. We place the transducer on our 4' x 22' x 3cm marble counter top. We get music (rather loud at that). We then place two pieces of 5/8" stacked drywall on the counter and the transducer on the stack. Still get loud music. We then lay two 5/8" pieces on the counter (laminated with green glue between them). No sound. No music. Technically, this is impact noise, but the demonstration effectively illustrates dampening.



Dennis,

Might you have had a chance to make a similar stack of drywall using a conventional adhesive, and then compare to the Green Glue stack?

Thank you.

Regards,

DG

Might you have had a chance to make a similar stack of drywall using a conventional adhesive, and then compare to the Green Glue stack?
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.

When asking Dennis about what of 4 different options I could/should use (including the combo of GG AND RSIC clips) his response, CONCERNING MY ROOM, was to use the fallowing building materials in the following order.

Stud > Green Glue > 5/8 drywall > Green Glue > 5/8 drywall.

Again I do not know if this is the "universal recommendation or the answer to my needs. I do know that it appears to be much easier to deal with and allows me to keep more headroom and width.

I've read many posts suggesting 2 layers of drywall. Many suggest 5/8" and 1/2" and others suggest 2 layers of 5/8". Obviously, for the purpose of more mass, 2 layers of 5/8" would be the answer. What about 5/8" firecode which is even more dense? What is the preferred? Is there a preference of hanging the drywall vertically or horizontally and on what layer is each direction preferred, if any?

Also, when using 2 layers of drywall and GOM to cover, does each layer of drywell need to be finished (mud and tape)?

The recommendation for 2 different sizes is that they have different masses and thereby theoretically different resonances that will help to cancel each other out.

If doing 2 layers, you should caulk the seams at a minimum. The mud and tape doesn't need to be anything fancy, just something to cover the seam and add some mass to the joint where there is potential air leakage and a weak spot. Make sure to also seal the intersection where the bottom wall plate meets the floor.

You can go the same direction or different directions - really up to you. If you are going to go different ways, I personally go horizontal on the inital layer and vertical on the visible layer. This way, you have no 'butt joints' to deal with when taping and mudding to get an easier smooth flat finish. Also plan ahead and 'double up' some studs at where the seams will be (it will make your life much easier for a few extra bucks) and make sure that the seams from 1 layer don't line up with seams from the other layer.

When you put the drywall up, make sure to overlap the seams from the 3 surfaces:

Layer of ceiling
Layer of wall
Layer of intersecting wall
continue around the room
Layer of ceiling
Layer of 1st wall
Layer of intersecting wall
continue around the room



Make sure to caulk all of the joints and seams. The alternating pattern provides less of a straight path for sound to move through and provides nice places to thoroughly caulk and seal the joints. Also make sure to glue the layers together thoroughly with Liquid Nails to avoid rattling UNLESS you are going with some sort of CLD (vinyl, Green Glue, etc.)

Chaz,

Green Glue, as Dennis mentioned, is designed for use between panels and can be utilized between any surfaces so long as one is porous (to allow the material to dry). An additional benefit in floors is reduced impact noise.

A tool is supplied with each order, application is the same for floors as walls, and coverage/gallon is ~60 square feet.

Regarding Drywall Adhesive acoustic performance (or lack thereof) please refer to the second graph here:

http://audioalloy.com/green_vs_other_damping_systems.htm

Just curious, how are we getting cost calculations that RSIC might be less than Green system?

mleineke,

You are more than welcome to stop by anytime and look at my theater, however Green is manufactured in the far away land of Fargo.

Best of luck on Green Glue, Audio Alloy guys! I'm looking forward to seeing the certified lab Transmission Loss Reports.

Regards,
Terry

Ted,

Where did you see something about RSIC being cheaper than Green Glue? I must be blind.

The drywall glued with liquid nails had no discerable differences to non-glued (just stacked) drywall pieces.

Thanks.

DG

bpape,

That was in reference to a previous comment in a post. With the Power Buy, Green is quite a bit less obviously.

Ted

Is there an expiration date on the power buy? What is the shelf life of Green Glue in an unopened container? I am just in the planning stage of finishing my basement which will include a theater so I would not need to use it for at least 4 months but it would be nice to take advantage of the power buy price.

Thanks.

Mark

Hi Mark,

We haven't set an ending date quite yet. When we do we'll announce it and you can decide then. It has great shelf life, but you may as well buy it closer to when you need it.

Ted et all,

I fear that it was my comments, in a previous post, could lead someone to the conclusion that the GG is more than the RSIC / Hat channel.


Originally posted by E. Martin

It is not cheap but the power buy helps greatly and I have all assurances that I will be thrilled with the results of the treatment. I am building a room that is 14'x9'x26'. You start adding up the sq feet involved in walls ceiling, stage, riser :eek: the numbers get big. I will get the added benefit of getting a bit of interior room back, as I am using dual 5/8 rock (Green Glue between) rather than the clips, channel, and 1/2 over 5/8 (clips remove a bit over 1 3/4 of interior space per side). I was tight in my isles so every inch counts!

To be clear the original DE design was to use the RSIC clips and channel on one full wall (adjoining the rest of the basement) and half of the ceiling. Half of the ceiling is built below the above floor joists for added interest and to clean up the lines. The other half of the room is at its full 9' height and needed the clips and channel. The rest of the room was built as near to "room with in a room" as I could get.

So, the Green Glue being much more expensive is based on the fact that I can even more effectively treat my ENTIRE room (all four walls, Ceiling, Riser, Stage) with GG rather than using the clips and channel on 1 wall and 1/2 ceiling. There is a tremendous price difference between he two plans. However there is also a tremendous difference between the performance I will get out of this room with Green Glue treatment through out.

If one was to compare apples to apples the Green Glue is far less expensive. I also have the added benefit of being able to hang my NEC XG852 from wooden joists/blocking rather than doing so from the clips and channel. Dennis assured me that I would be fine (and I believe him) but I like the idea of lag screws into wood!!!!!

Hopefully I clarified what might have lead to some misunderstandings and misconceptions about the pricing.

Thanks for the clarification! By the way, I like that projector! Another CRT guy, way to go!

In my experience, GG and RSIC/Hat channel cost about the same. I'm doing both in my HT because I only have one chance to build it, and I doubt it's ever as quiet as I want and I don't want to think "if only..." for the next 20 years.

I've got about 50% of my second layer of drywall up, and 100% of both layers on the ceiling. I've gained some experience applying the green glue and would like to mention a couple things:

1) I found Ted extremely customer oriented. I had an issue of my own making and he dealt with it above and beyond what I would have expected him to. Highly recommended.

2) The product can be messy to install. It's sticky, gloppy, and gets everywhere. In short, it's glue. A large, green bucket of glue. ;)

3) For this reason I would recommend to any new installers that they:
a) make sure there is nothing in the room they don't mind washing.
b) have lots of rags on hand (the shop rags you get at an auto store are great).
c) have lots of patience.

4) Based on my experience I strongly recommend the following specific techniques:
a) For ceiling application, apply the GG to the drywall panels on the ground and then lift them into place. Troweling this stuff on the ceiling is NOT fun and leads to very messy hair. Need I say more.
b) Applying the material to the panels is easiest with a large heavy brush. The one I'm using is about 8 inches wide and very coarse - it's more like a heavy plaster brush than a paint brush. Trying to trowel it on directly or with a spatula like drywall compound has led to lots of glops all over the floor and arms/legs in my experience. Maybe others have more skill than I do, but applying it with the brush and then going over it with the notched trowel has been far (far!) easier in my experience.

I have found it takes me about 10-15 minutes to apply the GG to each 8' x 54" section of wall space, and then another few minutes to shim the drywall in place and screw it in.

I can't speak to performance yet, as mine has not cured and I don't even have a door on my HT yet, but given the data at the website, and Dennis' recommendations, I'm happy thus far with the money spent, though it was a fairly large chunk of change. However you only get a chance to do the room once, you can always buy a more expensive projector later on....

Originally posted by PAP
a) For ceiling application, apply the GG to the drywall panels on the ground and then lift them into place. Troweling this stuff on the ceiling is NOT fun and leads to very messy hair. Need I say more.


I thought your were going 'punk' with the green hair. Or maybe getting ready for Halloween.
;)

Great thread, starting to get a better understanding of GG.

I’m still in the planning stage, I’m mostly done w/ studding out the walls, but with electrical work, my work and schedule coming up, drywall may be more than a month away. Prior to the mention of GG, my plan was to use RSIC clips on all walls & ceiling, hat channel & 2 layers of drywall.

But this thread has me wondering – is GG & RSIC an overkill? Dennis told Justin in this thread to use Green Glue – are you saying forget RSIC? If that’s the case, great, cost & space savings are always appreciated. If that is what you are saying, Dennis, it’s saying a lot, as you are a supplier (to many of us here) of RSIC clips – this will be eating a bit into your pocket.

However, I’m with PAP – this is a one time build so having a sense of the relative benefits of one or the other as opposed to both would be useful.

Just what I needed, more things to keep me up at night to decide….

Originally posted by Dennis Erskine
The product is worth it even for room within room type of construction.

We've not only used the product; but, have a pretty interesting demo in the store.

We have a transducer ... one of those items designed to be attached to a wall or ceiling to create a PA or background music source. We place the transducer on our 4' x 22' x 3cm marble counter top. We get music (rather loud at that). We then place two pieces of 5/8" stacked drywall on the counter and the transducer on the stack. Still get loud music. We then lay two 5/8" pieces on the counter (laminated with green glue between them). No sound. No music. Technically, this is impact noise, but the demonstration effectively illustrates dampening.

I hope this is not taken in any negative way but... I would like this cleared up, is Dennis affiliated with Audio Alloy in any way? His endorsement of GG is quite impressive and I know Dennis sells/sold the RSCI clips as well.


Craig :) :)

Hi Craig,

While Dennis isn't part of Audio Alloy, he was an early adopter and resource for us. I guess he's been around the product longer than most here.

Ted,

A suggestion... have you thought of offering a small sample (maybe a quart for $20?) of the GG to allow any one of us to duplicate the DE demo and to get a feel for working with GG? I would certainly be interested in obtaining a quart of the material before ordering 15-20 gallons of something I have no experience with.

is Dennis affiliated with Audio Alloy in any way? His endorsement of GG is quite impressive and I know Dennis sells/sold the RSCI clips as well.
I have no affiliation with Audio Alloy...just the good fortune of working with it early on in its development. I am not, by the way, a distributor for the product. I believe it is sold only directly from Audio Alloy.

I also do not own any stock in the company which I sense will be my own misfortune.

--- I'd like to add the following to this:
I'd don't get paid, nor would I accept a fee for a product "endorsement". I'm not in the endorsement business. For a product to fall into our "approved" list (which means we'll use, or specify, the product in our own work..or my own home):
1. The product must perform exactly as stated, or better than stated;
2. Any claims must be backed by appropriate testing where applicable;
3. The company must provide exemplary customer service;
4. The product had better work the first time everytime;
5. The product (or service) must be of very high quality and of consistent quality.
6. The company's marketing does not mislead, overstate, misinform or "imply";

Examples are SVSubwoofers, Lutron (ISO 9000 and 6Sigma), Stewart Filmscreen, Audio Alloy, PAC-International, among others.

Let me put it into my perspective as a flight instructor ... if I'd let you fly my family, you'll get the signoff/endorsement in your logbook. If not, we still have work to do.

Hi Maddog,

I don't know that we'll be sending out "practice quarts" anytime soon, but you never know;)

It's just troweled on.

After reading all these posts I am wondering if I should include GG in my build. Below is a the current construction detail.

Front and left wall: Concrete block, furred w/2x4 w/ R19 batted, 1/2" GB (existing w/o GB)
Right and back wall: 2x4 w/ 3" Wet Cellulose, RSIC-1, 1/2" GB
Ceiling: 12" Joist filled with dry Cellulose, RSIC-1, 5/8" GB
Seats are 123.4" and 48" deep. (rows of 4's recliners, maybe 3 @ 93")
Rear seats are on a 10" raised platform.
Seats are 3" off the left wall and center to the screen.
Stage is 4" filled with sand.
The gap between the seats and right wall is 23" or so.

Any suggestions would much appreciated....
I included a basic drawing of my HT.
Tkawika

Why wet cellulose on the side walls?

Three reasons:
1st: Its free...
2nd: I was under the impression its a decent sound dampning material.
3rd: Its free again. Installation and material.

Wet Cellulose is blown in wet and then drys to a firm dry cellulose. If you understood that, I apologize in advance.

Yeah, I understand what it is. No apologies needed. Don't get me wrong, free is always good! I've never used this type of product for HT purposes so I can't say for sure. Just my impressions.

However, I think it acts more like styrofoam from an absorbtion standpoint (could be wrong here) due to its lack of transmissiveness (word?). Also, since it dries solid and has no flex to it like the dry stuff or normal batts, it also makes another path for physical transimission of sound from one layer of drywall (inside the room) to the other layer (outside of the room). It will still help damp the cavity resonances so if isolation is not a major concern, it should work OK.

How well or poorly would this product work with only 1 layer of drywall? (ie. Stud -> Green Glue -> 5/8" Drywall)

How does this product compare to the "other guy", QuietGlue?

Andy K.

In looking at that theater, I'm not so concerned about cavity resonance as I am panel resonance.

Andy, there would be some benefit to treating the stud edges only, but any real difference will only come from the majority of the surfaces being a constrained layer with Green.

As far as other types of materials performance, take a look at the data here:
http://audioalloy.com/green_vs_other_damping_systems.htm

Oh, as an aside - I notice the use of cellulose above. How does cellulose compare with something like Roxul Safe n Sound?

Andy K.

cellulose and mineral fiber have both been demonstrated to be superlative sound absorbers, and superior to the fluffy stuff at mid/high frequencies.

at lower frequencies, it's a crap-shoot, so to speak. wall behavior there is dominated by the interplay of mass and resonance for the most part, and it's not realistic to say either one has a definitive advantage relative to the fluffy stuff. some studies have concluded that plain fiberglass batts are preferable to more exotic materials on the low end.

either is a fine choice, as is the same $$$ worth of plain fiberglass.

putting studs and an air cavity in front of a concrete wall can yield considerable resonance problems that reduce performance at lower frequencies. the following are sensible methods to coping with that

1. utilize as deep as humanly possible resilient connections (like flexible steed studs, wood studs with clips, etc.) and insulation.

1a. damp the panels to mitigate that component of the resonant behavior

2. if using wood studs, damp the panels to mitigate the resonance problem AND, again, utilize absorbing material. a variety of panel damping products are available as well as pre-damped engineered panels.

good luck everybody!

Ted White wrote:

Green Glue, as Dennis mentioned, is designed for use between panels and can be utilized between any surfaces so long as one is porous (to allow the material to dry).

Er, I guess I'm confused. Is sheetrock considered "porous"? I thought the idea was to use Green Glue between two pieces of sheetrock, to create a mastic CLD layer.

Also, I would like to "chime in" for support of you selling 1 quart "samples" as well.

Thanks.

Drywall is porous, yes, allowing the Green to dry. (Glue has to dry). The result is a constrained layer system with the Green bonding the two layers together.

Are there any install insrtuctions? How thick to put it on. Special drywall screwing instructions. (That didn't come out right!) Days required to cure/dry, Etc.

Ted, (BTW Great name)

First I want to say this forum rocks.

Would it be better to fore go the RSIC clips and dble up the GB? As you can see in the paint drawing this would help with the isle next to the seats. I read a previous post that Dennis recomended dble GB w/ GG over the RSIC clips or should I do both and have theater for 6 instead of 8?

Ted K

Ted,

RSIC clips are a great product. If you're saying that by using them you have to reduce your seating, I would consider an alternative.

Directions are fairly straightforward. It's a glue that gets troweled on with our supplied trowel. Sandwich the drywall before Green dries. Done.

drywall, greenboard, OSB, plywood, MDF, particleboard... all of these are sufficiently porous to allow the material to dry. dry time varies with the matrial (fast in drywall, slower in MDF, for example), ambient temp, and ambient relative humidity. you can use one porous layer (drywall, wood, etc.) and one non-porous (painted drywall, metal, concrete, etc.) as well.

concrete is probably sufficiently porous to allow it to dry eventually

So, it's a thin enough layer so as to not have to be considered in room demension calcs? If you take my meaning?:)

Originally posted by Ted White
Ted,

RSIC clips are a great product. If you're saying that by using them you have to reduce your seating, I would consider an alternative.

I guess what I mean by "reduce seating" is that in a 2 row 4 seat configuration if I use RSIC clips and dble GB then instead of having 23" isle, it would be around 20" or 28" if I only use dble GB and GG. Is 20" enough, ok walked into that one, but is it?

Ted

Originally posted by Rutgar
Also, I would like to "chime in" for support of you selling 1 quart "samples" as well.


Or one gallon tubs, if for no other reason than to accomodate those of us that buy two 5-gallon buckets and find out that we came up about a gallon short. :)

Is the PRIMARY purpose of the damping to contain the sound from the HT from the rest of the house or is it to keep vibrations from causing sound problems within the theater?

Building 12x9x20 ht... one wall solid concrete others 2x4 studs..just realizing that my planned single 5/8 inch sheetrock may be a problem.

The primary purpose is sound isolation, not in room acoustic response of the room.

....a 201J jockey

Dennis,
In your opinion, would the combination of GG & RISC be overkill? Or would GG provide significant isolation, with RISC providing only marginal enhancement? Or visa versa?

Many thanks,
Bob

Bob, in HT there is no such thing as overkill ;)

I suppose not - certainly there's not such thing as over thinking!

Originally posted by JustinS
Or one gallon tubs, if for no other reason than to accomodate those of us that buy two 5-gallon buckets and find out that we came up about a gallon short. :)


Spoken by a fella, who like me, has come up short and has had a gallon of "whatever" save his ass. :cool:

One gallon sizes and five gallon buckets are perfect volumes for the application at hand.

I know it was asked earlier, but I didn't see an answer: What is the shelf life of Green Glue?

Thanks.

for wet glue: shelf life is at least several months, currently test samples have aged 9 months without issue, we guarantee 6 months for all current material

Great product. Looks like the option for me. I have a small room 11x16x9 and using RSIC clips will rob me of precious space. My concerns are long term performance. How is this product going to be performing 5 years, 10 years, etc..from the day it was installed ?

Regards,


Ivan

good question, Ivan

our lab has, from another source, a sample of this type of polymer that is 20 years old (stored indoors, no light) and it's in fine shape

heat aging tests are excellent, and every reasonable effort has been made to further stabilize the stuff, so...

i guess the best way to know what it will be like in 10 years is to wait 10 years, but it should last decades

Thanks, Brian !!

Ivan

Hi-

I am in the planning stages and intesively researching HT construction. I have a concern with sound traveling through the ceiling, but I also have a concern with reducing the ceiling height. Do you really need to 5/8 pieces of drywall to benefit from GG or can you just put a 1/4 layer on top? Will GG eliminate the need to insulate between floors? I was planning on using batting to dampen sound. How much of a benefit will I get from just using one piece of drywall, but adding GG on the joists?

Thanks,

Tweakophyte:

Have you been to http://www.audioalloy.com ? Lots to read there.

For example with your question How much of a benefit will I get from just using one piece of drywall, but adding GG on the joists?There's Green Glue On A Budget (http://www.audioalloy.com/green_vs_other_damping_systems.htm) which talks about the change in damping using 50% of the surface area. You might be able to extrapolate the effects for just the joists since the joists on 16" centers would represent 9% of the surface area.

I would think there would still be a benefit to doing GG between layers no matter the thickness (within reason). However, the additional mass offered by an extra 3/8" drywall (5/8 instead of 1/4) is a great isolation benefit compared to 3/8" loss of ceiling height.

the use of 1/4" drywall with 5/8" or 1/2" instead of two thick layers is interesting. we will have concrete answers to that in one week :) it should work fine, biggest difference being a bit of lost mass.

Originally posted by bob md
Dennis,
In your opinion, would the combination of GG & RISC be overkill? Or would GG provide significant isolation, with RISC providing only marginal enhancement? Or visa versa?

Many thanks,
Bob

I'm wondering about this exact thing for a project I'm currently working on. Any verdict on this?

Ed B. 1979:

RSIC decouples the gypsum from the studs, increasing TL, including the first impact.
Green Glue damps the resonant vibrations within the gypsum faster than gypsum alone, affecting both TL and in-the-room sound.
Seems to me that decoupling (RSIC or double stud wall) would work best in concert with Green Glue.

Hi all,

I'm really interested to see the effect of green glue in an objective comparison with other walls.

Not the traditional worst case wall versus whatever.

This should be usefull information.
I've seen now the damping curves on the related site.

If the idea is to apply it in practice comparisons should be made with practical solutions in a wall itself.

Just a thought. Or are such TL curves published already?

Kin,d regards
Eric Desart

Eric Desart:

http://www.audioalloy.com/green_glue.htm says "data for transmission loss, impact noise" are coming soon. Presumably that will be 3rd party lab data.

Is Green Glue a substitute for sand in the stage and riser?

Skip

sand in the stage and riser?

Not a substitute for sand in the stage no. It is not required in the seating platform.

hi all,

those interested in small sizes: it's under discussion!

eric: i thought we chatted about this once? lol it should be lots of fun!

stages: we're close to wrapping up a research project on this topic - on stages with Green Glue. What we are assessing is vibration transfer to the floor/slab with a variety of vibration sources.

take care all and happy monday

Brian

Originally posted by brianr820
hi all,

those interested in small sizes: gallons for doors will probably come to pass, and no question some jobs will need that bit extra now and again

take care all and happy monday

Brian

It would be nice to have some choices for different sizes. Especially when the cost is a factor. Why waste two gallons of Green Glue if you don't have to?

BTW, as soon as I get back from vacation, expect a call from me.

Are there any known health risks to green glue? Asbestos was a wonder product when it came out as well. I would just like to know a little more info on what it is made out of before I coat the inner walls of my entire theater with it. Also how does green glue react when burned? Are toxic fumes produced?

hi Chris,

those are very good questions. it is a waterborne, latex-based product, and as such whatever safety precautions apply to normal latex paint should be applied here as well.

in combustion it, like all things, can generate smoke, carbon monoxide, etc. I am not aware, nor are the makers of any raw mateials, of any accute or specific danger of burning Green Glue.

it's waterborne material, handle it will all thusly applicable precautions.

Brian

Wow this is great news! I hope the discount lasts for a while, as I won't framing for a few months.

I will be building in the basement. I have forced air duct hanging from the ceiling/joists. I will need to frame around this duct work. the framing will have to be beefy enough to hold 2 layers of sheetrock. should I apply some goo to the framing members (between member and joist)? or just apply to the surfaces that will touch the sheetrock?

I'm planning a three layer wall sandwiching 1/2" homasote between two layers of 5/8" blueboard. Should I use GG on both sides of the homasote?

Is this a 3 db improvement, or more?

Also, is GG a good idea between subfloors in the room above?

Couple of more questions. From what I've pieced together even in a room within a room or RSIC type scenario, green glue will help because it help dissipate the low frequency vibrations better than normal. Hence less resonant problems.

In my situation I'll have an air cavity in between drywall and concrete so resonation is a big issue. Would green glue between layers of dry wall AND a layer rolled onto the concrete be superior over simply putting it in between the drywall?

hi Ken, the homasote (or other soundboard) + Green Glue is an interesting question, and one we're in the process of looking at. damping results should be available soon for a variety of 3-layer structures, including the one you mention, i'll relay when available. I don't know how expensive soundboard is in your area, but a central drywall layer may be heavier & cheaper

Hi Ed, you can damp thick concrete with Green Glue, but just putting a layer on top won't do much. It's what's called a "constrained layer" damping matrial, and functions when used as the center of a sandwich. NO paint-on damping material anywhere, now or ever, will meaningfully raise the damping of thick concrete at anything resembling a reasonable cost. (that's just an inherent drawback of paint-on damping - inability to affect resonance in thick, stiff things)

if you wished to damp concrete you could create a sandwich of concrete/Green/plaster, i'll make sure that data finds it's way onto the site ASAP as well (things are busy in there parts, lol)

i'll be back with another thought on the concrete + air cavity issue later this week

take care all and thanks for all the posts

Brian

"it is a waterborne, latex-based product, and as such whatever safety precautions apply to normal latex paint should be applied here as well."

Any test by independent laboratories on the horizon to verify safety and non-toxicity of product?

hi Frank,

well, as you've never seen a study for toxicity of a latex paint you'd find at home depot, etc., you probably won't find one for Green Glue. Top of my head i'm not aware of that type of study being available for any (specific, individual) commercial product of this type (latex), if you can find one let me know, but i'd be surprised. Go to HD and ask for a specific study on some formulation or color (each color presents a slightly different toxicological profile).

Toxicity of products like these is assessed via analysis of the components. (a put cyanide in a latex paint and there is cause for concern. we opted to skip the cyanide (heehee)

the material may be handled like a latex paint (wise to use gloves, not eat the stuff, and all the other things you'd do with a latex).

hope that helped

Brian

whatever it's worth, the process of UL testing and attainment of a "Green" listing are underway

Thanks Brian.

What exactly will UL be testing for?

Regards
Frank

Green Glue is indeed classified as "Green" by the Green Building Council.

www.usgbc.org

Adhesives with a VOC less than 200g/l qualify as "Green" and Green Glue is under 20g/l.

Maybe a silly question. Are screws needed on second drywall layer? or just enough screws needed to hold the drywall in place while glue cures?

- HM (first time caller)

Hi Ho,

That's not a silly question at all! You want to secure the first and second layers with screws. Thanks for the question.

I would ask Ted or Brian directly (as I am now very, very interested in this product), but others may benefit as well...so I'll ask here. Anyone else who has familiarity, please chime in as well.

1) Staggered Drywall-Do you recommend the common approach of staggered and sealed layers of drywall (i.e. seams don't overlap other seems exactly, each layer is taped, caulked, etc.), or is it better to sandwich individual drywall sheet over another sheet in a flush manner, or does it not matter?

2) The Sirens' Song-The allure of NOT having to reframe a room inside a room to get good isolation results is truly a sirens' song for me. This would leave me with significantly more finished room in my existing 15'x21'x9' room, as well as decrease my labor costs (i.e. my time) greatly (not to mention material costs). Is it silly of me to hope that using this product applied at 100% coverage with new drywall over the existing, painted drywall and ceiling may approach the isolation provided by room inside a room? Sounds to good to be true, but I am hoping. As an example, if I measure 75 dB of sound pressure in the room (which is currently my media room, soon to be converted to dedicated home theater room) from a typical musical source (i.e. lows, mids, and highs), I maintain about 73 dB of pressure, seemingly ALL from about 400 hz or less, in the master bedroom above. This "low frequency concert" does not bode well for WAF. I need to lower this to livable (i.e. sleepable) levels if I am to succeed in my sound isolation endeavors. Please address this issue for me if possible. I realize room in a room AND GG would be probably better, but help me out here. :)

3) Insulation-Related to number 2 above, if I were to go the route of new drywall over old with GG in between, should I cut holes strategically in the existing drywall to fill cavities with batting or other insulation, and then patch the holes before applying GG and new layer?

4) Rigid Coupling-By now you see I am no expert, but it seems to me that firmly attaching both layers of drywall to the existing studs with drywall screws would negatively affect the isolation by providing tightly coupled escape routes for vibrations. How is this countered by GG? Or, am I way off base here?

5) Peaks and Valleys-Lastly, and this is just to satisfy my overactive curiosity, after the toweled application of GG, does applying the outer sheet (in my case, drywall) leave air pockets in the trowel valleys of the wet green glue, or does it press the glue into a normalized, solid layer?

Thanks in advance. I hope answers to these questions will be useful to others here as well. I'm looking forward to ordering some of your new product in the next few weeks. I think I hear the sirens singing now…

Bill~

The low frequency sound level only drops from 75 to 73 db when traveling upstairs?! How are you measuring that? It's enough to make me nervous about my project.

Can you measure again with either pink noise or sine waves at various frequencies? I would love to see before and after numbers, even if they are from a typical room instead of real lab measurements..and I'll bet a lot of other folks would be interested too.

Thanks

In screwing the two drywall layers how many screws would you recommend on the first layer and on the second layer if one is using green glue between the two layers. 5/8" will be attached to joists and stud walls followed by green glue and then 1/2".

Regards
Frank

Frank D:

Same rules as without green.
Minimum course of screws on the first layer, and then a full course on the room side layer.

Originally posted by kwolff
The low frequency sound level only drops from 75 to 73 db when traveling upstairs?! How are you measuring that? It's enough to make me nervous about my project.

Can you measure again with either pink noise or sine waves at various frequencies? I would love to see before and after numbers, even if they are from a typical room instead of real lab measurements..and I'll bet a lot of other folks would be interested too.

Thanks

Ya...scary, eh? This is in the room as it was built (I haven't done anything to the room yet). It amazed me, too, but there it was. I measured with a simple SPL meter set to C weighting and slow response using a music source that had a normal amount of low-range stuff (not overly boomy).I measured the primary listening postion downstairs, then stood in the middle of the master bedroom upstairs with the meter horizontal at about 4 feet off the floor. I also measured using pink noise, but I don't remember the results. As expected, it is really only the low end that vibrates on through the ceiling and floor above. I'm sure much of it is going through the structure of the load bearing wall that is shared with both rooms.

I will do another measurement hopefully within a day and post the results for you. I don't think I have a source for sine waves (specific frequencies), but I should be able to do pink noise. I'll let you know. I was going to do before and afters anyway.

If you can play MP3 files, here (http://www.snapbug.ws/sinewaves/) is a source for any specific bass frequency wave you want to play.

ok, a few things to follow up on here.

Ken - yes, damping floors is particularily advantageous

about screws - use what code requires, no need for more, don't use less. this isn't a situation where screwing causes failure ala resilient channel...

test results for 1/4 drywall/homasote sandwich - couple more days :)

BillWil, and all. When measuring the volume of low frequency sound making it's way from one room to another, make sure to measure at MANY locations in both rooms.

the reason for this is that room modes, and reflections/interference and the like can cause considerable peaks and dips in measured volume at different places in the room. Perhaps you've seen the plots with big peaks and dips - ala the Bad Bass thread?

So if you measure one room at a dip at the frequency in question, and get, say, 78db, then measure the next room at a peak at the same frequency you might get 79db and conclude that your wall actually amplified the frequency.

if you measure at many positions in both rooms and average them you'll garner a better idea.

one point that you touched on that is very true, is that stopping low frequencies is the grand challenge.

take care all,

Brian

How does this product stack up against any weighted vinyl barrier sheeting, or even good old roll roofing? This product gets very expensive very fast, when a 5 gallon drum, listed at $220, only covers 60 sq ft. Not for the budget minded, by all appearances.

Have you priced the mass loaded vinyl you referred to?

Green covers 60 square feet per gallon, not per 5 gallon pail :)

hi all,

the lab would like to apologize mildly for the somewhat slower than expected response to some of these questions, lots going on and we decided that running each test agan would behoove us before making a comment.

1/4" drywall with 5/8" (this was asked for space reasons, i believe?: recommended, this does an acceptable job and performance is different than, but similar to (with respect to damping) 5/8" wih 5/8". as is the case almost more with Green Glue than with no adhesive, the differing properties create chaotic behavior which may have some additional advantage.

drywall/green/homasote/green/drywall - recommended, and worth further exploration. Damping was superior (considerably) to drywall/green/drywall (one damping layer). The same would apply to drywall/green/drywall/green/drywall, however, and no particular advantage is noted for utilizing soundboard as the core at this time. The unique surface characteristics of that type of product (fiberbaord/soundboard) offer some promise for future work. :)

suffice it to say this: you will attain superior damping AND superior mass by utilizing

drywall/50% coverage Green/drywall/50% coverage Green/drywall

than

drywall/green/drywall

and if you can tolerate the mass/labor expenses (if applicable)/space, whatever of the extra layer you will be rewarded.

later this week i/we hope to catch up thoroughly on this stuff here, and i hope to finish what i started a while back with the general guidelines to sound isolation. :)

Brian

brianr820, thanks for all the hard work!

Hmmm,
I wonder about using strickly 1/4".
1/4" DW/GG/1/4"DW/GG/1/4" DW.

Probably would be better (maybe) than
1/2"DW/GG/5/8" DW

Or not:).

I have never seen 1/4 inch drywall! I thought it was just a typo before. Is is some sort of special order item? I always see 1/2, 5/8, Green board, sound board, cement board, etc. But no 1/4 inch. I would think that would snap too easily.

hi guys, we'd never had it in the lab prior to this request, either, the only drawback that i can see is that it's NOT VERY STRONG, lol

they use it, i'm told, to make curved walls often - those walls probably really need some Green.


just for fun, discussion purposes:

your idea, (bobMD) has merit - 1/4" drywall would have VASTLY lower wave-speed, stiffness, and somewhat higher damping (Green Glue doesn't really "crap-out" on thick things, so probably not immensely higher) - and the destruction of vibration over distance would be overwhelming.

talking about normal 2x4 walls only:

also, you'd lower the walls resonant point (pros and cons to that i suppose)

the big drawback is that you'd lose mass... and that will play a considerable role in the subwoofer region (low frequency performance is primarily mass minus resonance), and i think most people would be better served by the heavier wall, although i would offer that mass-for-mass, layers of 1/4" and green would be expensive, but superb.

for de-coupled designs (RSIC, room-within-a room), use the heaver drywall, as the mass has even more benefit there.

take care all, and don't hesitate to post whatever is on your mind, never know when a thought will turn up something really interesting.

Brian

don't hesitate to post whatever is on your mind

Hey! How about a two-fer-one introductory offer on GG?! :D

Originally posted by Fatman513
Hey! How about a two-fer-one introductory offer on GG?! :D

Count me in! That way we could help spread the word about the product with some real usage, not just lab.

Regarding 1/4" drywall, yes, it's commonly available, at least in my area. Its main benefits are twofold:
1) it bends, easy to curve as mentioned
2) it's light weight - easier to carry, install, especially if you 1 person doing it

I've used it before, much easier to use than 1/2 or 5/8". However it can snap, as well I know! I won't be using it for my HT, but I wish 5/8" was lighter!

Well, my drywall installers just finished installing the drywall with the Green Glue barrier. They still have a lot of work in mudding, taping, etc. But I have to tell you they seemed pretty impressed with the Green Glue. The walls seem incredibly dense. A good rap on it with your knuckles sound like there is concrete behind them (there is only plywood and studs). Also, cleanup was a snap as this stuff is water soluable.

We'll see how it performs once the entire theater is done in a few weeks, but so far the results are encouraging.

You guys left out 3/8" drywall. The local Home Depot carries 1/4", 3/8", 1/2" and 5/8".

So, let me get this straight. GG can be just as effective as Acoustiblok, roofing rubber?

Is it only avalable from one company?

The cheapest price is $220 per 5 gallon bucket?

THANKS
vid53

Hi Vid,

$220 is the AVS Forum member price as part of a power buy. Green Glue is only available through Audio Alloy. I'd be happy to answer any application questions you may have.

Vid:

You're better off spending the money getting your room correct and spending less on speakers, electronics, etc. In terms of 'bang for the buck', Green Glue is the only game in town.

[i]Originally posted by PeterS

We'll see how it performs once the entire theater is done in a few weeks, [/B]

A Few Weeks....................

I don't care who you are, thats funny right there!!! LOL :D

hey Tedd, 3/8" drywall is fine, used as a sandwich with itself (3/8" / green / 3/8")

you may also use it with 1/2 or 5/8, thumbs up, and if you can tolerate it preferable at all times to 1/4", it's only 1/8" thicker and it's still pretty easy for one guy to handle (5/8" is the bugger there)

I've just received a couple of pails of Green Glue to get me started, and am weighing 1/2" verus 5/8" drywall over the existing 1/2" drywall and the walls. Locally 5/8" drywall is over $5 a sheet more then 1/2", and I am wondering if I am being tempted by false economy.

Anyone here suggest how to handle drywalling over existing electrical plugs? I'll be terminating the existing wall plug wiring going into the room (per local electrical code), and drywalling the second layer right over them. Do I need to plate these over with drywall, or would some expanding foam be suitable enough to kill the cavity? New wiring runs, in conduit, will be added to satisfy code with the wall plugs in the kicktrim, or columns.

hey Tedd, that's incredible - $5 more a sheet than regular 1/2" ....

here, in the last year, it has ranged from a buck more to less than 1/2", must be the old supply/demand.

i'll run some calculations based on changed mass to estimate the performance difference at very low frequencies and get back

That IS odd. Some places sell 3/8", 1/2" and 5/8" all for the same price.

As for the comparison with a rubber layer, I can't speak to it myself, by my contractor has used it before, and I understand it was a pain to use. The Green Glue is much simpler, and from what I can tell, should work as well if not better.

Again. Does it have the same isolation benefits as rubber? Remember. Rubber, Acoustiblok, has mass, lots of it. The more mass you can build, the better isolation. So, how can a glue have the same mass factor as rubber?

If your building walls with rubber and drywall, your talking major mass. If using GG, where's the mass?

ok, with respect to mass and sub-region performance on a 2x4 wall, the following calculations may be handy, they are based on the expected changes due to mass alone.

IMPORTANT NOTE: these will probably apply well in the subwoofer region, they will not apply at higher frequencies at all,

These are relative to one layer of 1/2" drywall on both sides:

double 5/8" both sides: +8 dB
5/8" + 1/2" both sides: +7 dB
double 1/2" both sides: +6dB
double 3/8" both sides: +3.5 dB
5/8" + 3/8" both sides: + 6dB
1/2" + 3.8" both sides: +4.9 dB
5/8" + 1/4" both sides: +4.9 dB

single 5/8" one side, double 5/8" other side: +5.5 dB
single 1/2" one side, 1/2" + 5/8" other side: +4.2 dB
single 1/2" one side, double 1/2" other side: +3.5 dB

(TEDD: from this calculation, it looks like utilizing 1/2" drywall in lieu of 5/8" drywall would cost you 0.7 dB if you were upgrading one side, and 1 dB if you were upgrading both sides)

single 5/8" both sides: +2 dB
single 1/2" both sides: +/- 0 dB

to convert from one possible construction to another, just subtract the two numbers.

i.e., for 1/2" + 5/8" to 2*5/8", take +8 minus +7 = 1dB of gain in this region for the heavier wall, etc.


i guess that's a few of the permutations, and it must be stated again that these predictions ARE NOT for all frequencies, but should apply reasonably well to frequencies below about 80hz and above wherever the wall resonates as a panel.

there are two low frequency resonances in this type of wall, the first tends to occur in the 80-200hz region, and the second much lower (perhaps lower than 30hz, or even at extremely low frequencies). Performance of all walls at resonant points is damping controlled, not mass controlled, performance of the walls at mid/high frequencies will depend on a wide variety of factors, and the extra mass of 5/8" drywall will not neccessarily be an advantage. BUT:

over the bulk of the subwoofer range, mass will be the most important factor (for an ordinary 2x4 wall), and the above should hold reasonably well.

to compare the above data to lab tests:

moving from 1 layer of 1/2" on both sides to 1 layer of 5/8" on both sides has a predicted benefit of +2 dB

in lab tests it delivered (average) +2 dB (IR-761)

for 3 total layers of 1/2 (1 one one side, 2 on the other side) the predicted benefit is again +2 dB, and test results showed +2.7 dB... (again IR-761)

generally, the data that i can find to browse shows results within ~ 1dB of the prediction for mass change in this region.

LET ME KNOW IF THIS ISN'T STRAIGHTFORWARD ENOUGH

Originally posted by vitod
Again. Does it have the same isolation benefits as rubber? Remember. Rubber, Acoustiblok, has mass, lots of it. The more mass you can build, the better isolation. So, how can a glue have the same mass factor as rubber?

If your building walls with rubber and drywall, your talking major mass. If using GG, where's the mass?


Ok, let's talk about mass for a moment... A sheet of 5/8" drywall weighs 70-75lbs... or about 2.3 lbs/square foot

if we added a layer of roofing rubber that was 0.8 lbs/square foot to a wall with 2 layers of 5/8" drywall on both sides, we'd raise the mass from ~9.2 lbs/square foot to 10, or about <10%

by mass calculation, that would translate to 0.7 dB of added performance.

if we added rubber at 0.8 lbs/square foot to a wall with just 1 layer of 5/8" drywall on both sides, we'd anticipate 1.4 dB of improvement.

if we used heavier, 1lb/square foot material, the impact on performance due to mass would be 0.9 dB and 1.75 dB due to mass for the two cases respectively.

so, the added mass of rubber simply isn't/can't be a considerable factor in performance.

looking at cost... let's say that our 1lb/square foot rubber cost 2 bucks a square foot. that's 2 bucks a pound. Drywall costs maybe 8-10 cents/lb.

so if you want more mass, add more drywall, seems alot cheaper.


anyway, to the question at hand: if adding a rubbery product to a wall has a transformative effect on sound-stopping performance, it's not due to it's mass, the mass is trivial.

it would be due to damping or some type of isolation effect (like rubber pucks, perhaps), or changing in the resonant behavior (moving it to a lower frequency to get higher STC). it's not the mass. you have to add ALOT of mass to really change walls. Now, drywall is stiff and very resonant and transfers energy very well, so perhaps roofing rubber attacks the resonance (damping) or the transfer (some isolation effect)

Green Glue sure isn't a mass-loading material, it's a damping material.

Roofing rubber isn't a practical or meaningful mass loading material, either, so it's effect has to be something else.

oh, hey, Vitod, i guess i got carried away talking about mass and didn't answer the

"which is better" question directly.

To the best of my knowledge, nobody have ever publicly offered a comparison of wall performance with and without limp mass, or even jsut with limp mass to leave us to guess as to what performance was like without it. that makes answering your question a bit harder, no? lol

i can simply say again that the mass of a roll of roofing rubber is largely inconsequential - drywall is far, far heavier, and it doesn't have a big change on overall mass.

and i can say simply that Green Glue is overwhelmingly superior as a damping material. limp materials have one big advantage over drywall - they aren't resonant. Well, Green Glued drywall isn't either (and it's cheap)

we have a large number of 3rd party tests now and in the near future, perhaps we'll pony up a nickel to answer the great limp mass question. Green Glue users won't be dissapointed. :) If we can squeeze it into our time/budget, we are also going to include non-green walls for as many of the cases as possible... since it's not feasible, or remotely, to compare data from lab to lab, that would give Green users the best idea of how things stack up possible.

So, rubber mass is not necessary as long as you have damping. For example:

stud>GG>drwall>GG>drywall. Correct?

What would be the STC more or less?

The rubber is not necessary and overly expensive for little to no benefit.

STC is meaningless for this application.

hey vitod, we'll release the tests when they are completed, and they'll have the STC calculations...

but what DE said holds: STC is just not a great measure of sound stopping at all.

STC disregards everything below 125hz, and even from 125-4000hz (the frequencies it does consider), it's calculation method is... not so good.

it stems from long, long ago when modern calculation speeds just weren't possible and a manual method for determining a rating was necessary.

Tedd:

I've just received a couple of pails of Green Glue to get me started

By the time you paid for import duty and/or goods & services tax, and customs brokerage fees if necessary, what was your final cost in Canadian $ ?

Thanks ... /FP

You have a pm, Ford Prefect. I guess I won't have the final costs until the charge card bill comes, but the Canadian dollar has made some impressive gains on the US dollar as of late. Sure beats a 50% premium I was paying as little as two years ago....

I have read the application notes .pdf from the website, but have a few questions:
1. "adhesive trowel" is this like 1/8" tooth vinyl trowel or a 1/4' tooth tile trowel?
2. What has anyone found a the best applicator for studs? same trowel? what about a "cake icing bag" type thing?

thanks!

I have a slightly different application that I don’t think has been covered in this thread. My dedicated theater room has three exterior walls and I get a very resonant – if that’s the right word – noise from outside passing traffic. We live in a developing neighborhood and there are a lot of work/delivery/utility vehicles that rumble down the lane. The walls of the room seem to amplify certain frequencies from the trucks and is REALLY distracting and quite loud. The facing wall is on the second floor and is about 25 feet from the road. The construction is 1/2” drywall+2x4 w/roll insulation+3/8” OSB+Tyvek+Hardiplank. Can I expect much attenuation of the low frequencies of the kind I am hearing via an application of GG and a layer of 1/2” drywall? Is another application more appropriate for this issue? Thanks!

hey sandwedg

1. is covered for you, you get the proper tool with every order

2. is something under research right now. The drywall tool works well, but improvements might be possible. A cake icing bag is a pretty slick idea, i'll have the lab gents take a look. filled conventional caulk tubes might be on the horizon :)

Bluetone

g'morning.

a quick side note: we experimented with some constructions once just to see if actual amplication of noise across a wall is possible in a case of severe resonance. the answer is affirmative, but that is a very tricky thing to measure with precision for a variety of reasons. i don't think the normal tests would ever reflect such a case.

on another quick side note: i worked in a building a few years back now that upgraded it's brick walls for higher STC. same effect, the low frequency resonance was so bad that the garbage trucks almost scared you if you were lost in thought. no high frequencies coming through, though! lol

with respect to your application, that is Green Glues very reason for being. do you have access to the outer part of that wall? can you treat (from behind, etc.) the OSB or whatever faces the street?

Brian

hey blue, is your construction

hardiplank / tyvek / 3/8" OSB / stud / drywall

at this time?

is there an air space between the hardiplank and the OSB? that's siding, right?

I just broke out the Green Glue last night and used the trowel to apply to the studs in the AV closet. It was time consuming for a single sheet and I doubt I'd have the patience to do a long run of studs this way. After reading the cake icing bag idea, I am wondering if the idea of a cake icer might be a good application tool. It is like a smaller version of a caulk tube (But refillable) and I wonder if the there is a suitable nozzle available to lay down a pattern similar to the notched trowel? As the Green Glue cleans up easily with water, this might work.

I just did a quick knuckle rap test on the 1/2" drywall/Green Glue/stud wall and the opposite wall 1/2" drywall/stud wall and I am impressed with a noticeable improvement in the wall already.

Brian - Yes, that is the construction. No air space between the OSB and the Hardiplank (fiber-cement siding), just house-wrap. I'm afraid that I can't get between the siding and the drywall w/o a crowbar. We just had the siding installed as a replacement for synthetic stucco. The noise level was more tolerable with the stucco. Are you thinking that the GG sandwich might be more effective somewhere other than between two layers of drywall?

hi all

Tedd, if you apply the Green to a sheet that is lying down by just scooping some on and spreading it, it goes pretty fast after a sheet or two. we just finished a survey of a couple of crews and also a few individuals and got ~4-5 min/sheet. I konw results will vary, i can't do a sheet in that time, and i think a video or two of that would help, i'll nag! anyway, good luck with the rest.

if you're working over an already painted wall, it's best to put the green on the painted surface.

Blue - i was just wondering if there was any way to damp the OSB, that's all. stucco is heavy, that helps with noise. Adding drywall + green to the inside should do very well if you can't access the OSB

:)

Brian, I just applied the Green Glue to the stud itself but after reading your suggestion, it just clicked in, that it makes more sense to apply it to all the sheet, on the first drywall layer. It is a dampening material after all... Somehow I had it in my mind as a "sandwich only" application. I still have access to the rear of the drywall to correct this. As this wall is common to a separate laundry room and a separate furance room, it is getting double drywall/Green Glue on both sides of the wall, studs filled with Roxul and a layer of Sonopan noise blocker.

Some of my construction is a retrofitting a second layer over existing 1/2" painted drywall (three exterior, insulated walls with pored concrete walls), with the common wall and ceiling pretty much being all new construction.

I was planning on running most of my drywall vertically. Buttering the rear of the drywall and standing it into place, horizontally applied, sounds alot easier then manhandling a 75 pound sheet of drywall, with sticky Green Glue applied, four feet off the ground for the upper horizontal run.

Good morning all,

The Green Glue is a part of a constrained layer damping system. To operate at maximun effectiveness, the Green needs to be applied in between two rigid layers. This can be two layers of drywall or two layers of subfloor, etc.

A sandwich is, in fact, what is needed.

Thanks!

Ted White just called me not two minutes after my last post and to clarify my misunderstanding:

Green Glue is to be used as a sandwiched material between two layers.

I expect Brian will get around to clarifying this but I don't want to be misleading anyone to wasteful use of their Green Glue.

Edit: (Boy oh boy is Ted White ever fast....!)

hi all,

Green has to be a sandwich, it can be effective only when sandwiched between two things.

there are two basic types of damping materials

1. constrained layer damping materials (sandwich damping materials) - Green is one of those, and a really good one

2. extensionsal damping materials - they sit on top (coatings, pads, ) - Green is thoroughly futile as one of these.

about extensional damping materials: they will all be fairly futile on drywall. Drywlal is just too stiff, and the fundamental limitation of damping materials sitting on top (not a sandwich), i.e. extensional damping materials, is that they can't control resonance in stiff things.

so they work very well on sheet metal and what not, but VASTLY less well on things that are stiff.

some damping materials work in both applications, but generally only when very thick and generally not ideally in either application. For anything around the price it is usually easy to make something far superior if you design it for one application or the other.

i'll try to remember to come back with some charts to illustrate

Brian

Originally posted by brianr820
hi all

if you're working over an already painted wall, it's best to put the green on the painted surface.

:)

Brian,

I assume the reason for this statement is because GG is water based and cures by the evaporation of the moisture, not some catalytic process. Does the unpainted dry wall soak up too much of the moisture too quickly if you apply the GG to the fresh drywall first? It would obviously be easier in retrofit applications, to apply the GG to a piece of drywall on sawhorses in a horizontal position rather than to the vertical wall. Could this problem be solved by pre-moistening the fresh drywall panel with a damp sponge or some other technique?

hey maddog,

i agree, it is very nice to put it on when the sheet is on the ground. after my comment today us lab chaps ran some tests on a painted wall where we put green on the new sheet, and laid it up, we'll report in about 7 days.

the convenience would be nice.

drywall does soak up water, good call, and Green dries faster in a sandwich than it does in open air as a result.

my thought was entrained air. the ridges from the trowel trapping little lines of air against the painted surface (the air can easily escape out through drywall/wood products, etc.)

one test will be done tomorrow (or monday if we don't have time to look at it tomorrow) to check for said entrapped air. if there is none, then in all honesty the other test is probably moot.

Brian

I post on installation when I'm done.

Can GG be used in addition to an In the Wall Barrier Acoustic Composite? Or would that be a waste of money? Thanks!

hey, i was just going to say "hi dork", then i realized you have an unusual screen name

so how's about hi 0900?

do you mean mass loaded vinyl? and if so, do you intend to put the MLV in between two layers of drywall, or in the air cavity.

i think most MLV sellers recommend the latter

take care,

Brian

two more things

first - someone mentioned the other day my comment somewhere herein that 3 layers with 50% Green on each layer would give higher mass (obviously) and also higher damping that 2 layers with 1 layer of 100% Green.

and that's true, but this gentlemans comment was that the drywall was by far the biggest expense. and i guess that's a regrettable fact of construction, eh? the materials are cheap, getting them in place isn't necessarily cheap at all.

In any case, we just offered observations on 3 layer walls with 2 damping layers, and they are really nice, however... 98% of the work we've done is on 2 layers sandwiches, so use whatever your space/budget/time/patience/code allows. :)


Second thing - about putting Green on pre-painted walls.

It would obviously be overwhelmingly convenient to be able to apply the Green to the new sheet, and not the existing wall. I'd expressed some wonder about the entrainment of air.

we've ran these tests many times over now, and we have not observed that effect, so it appears i was incorrect. in this case that's a good thing.

we're going to continue to look at it, but it does not appear that there is any reason to not utilize the material in this manner.

TAke care all

Brian

Ok, so I start on the framing this weekend!

A question that has crossed my mind... Is this stuff like peanut butter or more slimey?

Just curious about the application to a stud... like, will it all get smooshed out when you screw the drywall down? or is it heavier duty consistency?

thanks!

good luck with the framing, and happy thanksgiving

it's a light paste, not peanut-butterish.

B

Now the hard part...

brianr820,

I was wondering how effective it would be to put a composite layer of mass loaded vinyl and accoustic foam between the studs

and then

apply 2 layers of drywall with GG between them...

would this be effective or would it be a waste of money?

thanks!

Unlike many of you, we here in California do not benefit from a construction mindset that can conceive of the idea of a "basement". Sadly, when our land is arguably among the most expensive, and they are now building 3-storey houses on 4,000-square foot properties, NOBODY has opted to dig down :( :(

So, my theater is on the second floor of my new home. Despite the hideous costs, it is still a giant "cookie-cutter" home that I was not able to have customized. I did, however, pay to have all interior walls and floor insulated to help with soundproofing.

So, I'm trying to figure out the best way to revamp the room. I'm considering Green Glue and another layer of sheetrock on the interior walls. I will be building a wall across the back where the green "curtain A" line is on the diagram -- and I'll be soundproofing that wall, too.

However... what about the floor? The room is above a guest bedroom and the kitchen. Though the in-floor insulation does help dramatically, I am considering removing out the carpet -- since I'm going to build a platform and a wall (and run outlets into the floor for the Berkline 099's and riser's step lights)-- and then putting the carpet back.

If so, would I benefit much from putting Green Glue on the floor? If so, what should I put on top of the GG? (thinking like 1/4-1/2" wood of some form).

If so, I'm looking at about 700 square feet of GG... so I, too, would appreciate 1-gallon sizes!

Perhaps people here should sell others their leftovers :)

http://www.goglen.com/post/theater2.gif

Originally posted by dork0900
brianr820,

I was wondering how effective it would be to put a composite layer of mass loaded vinyl and accoustic foam between the studs

and then

apply 2 layers of drywall with GG between them...

would this be effective or would it be a waste of money?

thanks!

hi 0900, it's hard for me to answer that question, as i've never seen data for limp mass used in the normal manner (in the air cavity).

but MLV between the drywall/green/drywall sandwich and the studs sure wouldn't interfere with Green Glue's performance, so the result might be akin to whatever the result of MLV in a normal 2x4 wall is. in some upcoming tests, we are going to include this combination, as it seems to be interesting to many people. hopefully the results are great...

but without the results in front of me, the above is the best assessment that i have. :)

take care,

Brian

Whatever is not nailed down, is mine.
Whatever I can pry loose... is not nailed down!

duly noted! i'll have the lab equipment nailed down tomorrow. hee hee

nice picture, Glen! Green Glue is fantastic on floors. They tend to be screwed down rather tightly, and as such they tend to exhibit some substantially problematic midbass resonances as well as another problem, called coincidence, that is lower in frequency on a floor than a wall. Impact noise is another benefit of damping a floor, and reduction of flanking noise is another. A well-damped floor (or wall) makes a poor sound conductor, while normal constructions with conventional materials liek wood/drywall/concrete can typically transmit sound over great distances.

if you really want to attain a high level of sound isolation from the top down, treating the ceiling below is a great idea. Green Glue or RSIC clips are just some of the options. it's not impossible that the ceiling below has resilient channel...?

take care,

Brian

Brian,

Do you know roughly when those upcoming tests will be done? Thanks!


Quote:

____________

hi 0900, it's hard for me to answer that question, as i've never seen data for limp mass used in the normal manner (in the air cavity).

but MLV between the drywall/green/drywall sandwich and the studs sure wouldn't interfere with Green Glue's performance, so the result might be akin to whatever the result of MLV in a normal 2x4 wall is. in some upcoming tests, we are going to include this combination, as it seems to be interesting to many people. hopefully the results are great...

but without the results in front of me, the above is the best assessment that i have.

take care,

Brian

______________

hey dork, in the coming weeks, an exact date for when the data will be on the site isn't set, but ASAP in any case

:)

Originally posted by brianr820
drywall does soak up water, good call, and Green dries faster in a sandwich than it does in open air as a result.

Do we want it to dry, or do we not want it to dry? Seeing how this is a "glue" I guess it is supposed to dry? If it dries, what happens to it? Does it remain flexible? My understanding is that damping materials need to remain flexible.

If we don't want it to dry, would a layer of primer on the first course of drywall help keep the green glue from drying?

hey chris, it remains very, very flexible, and it should dry. it will exhibit good damping pretty quick (a day or even a few hours, conditions depending), but it should dry.

even if you put it between two sheets of glass, it will eventually dry unless you sealed the edges to be completely air tight. but drying is good.

take care,

Brian

i was thinking here in the wee hours of the morn about installation questions concerning Green.

it's straight-forward to use, spread it on, and screw, but sometimes questions do come up - things like wall texture and if the stuff will work with some given texture, for one example.

one fine gent commented that he'd asked alot of questions for a small order, but, see, here's the thing:

if some contractor orders 150 pails to make an apartment building, someone can just go demonstrate and make sure everything is exactly right. but you guys don't have that luxury, really. now, in 90% of cases minimum, it will all go fine, fine, fine, and AAlloy is making movies and taking pictures and timing crews using it and all of that, but these things take time, and it's not quite ready for the site.

but there are people to answer questions, the service is there, and if i was you i'd just go ahead and abuse it (the service). take pictures of your wall, ask that the lab test something similar, just spit it all out.

abuse is good!

Brian

and as long as i'm rambling, if you're thinking of using the Green feel free to fire questions about your room and construction in general. the folks here are reasonably nice, although i don't think there is a passable singing voice among 'em, competent in this general area (sound isolation), and you'll get a reply.

we are not remotely competent in any area of theater construction other than sound isolation, just to clear up my comment immediately above.

Brian

Originally posted by brianr820
Green Glue is fantastic on floors. They tend to be screwed down rather tightly, and as such they tend to exhibit some substantially problematic midbass resonances as well as another problem, called coincidence, that is lower in frequency on a floor than a wall.

So, given that I have particle-board floors currently under the theater, if I were to put down a layer of GG on top of them... what should I put on top? More particle board, or plywood, or some other substance?

Adding GG and sheetrock to the ceiling downstairs is out of the question. No way the wife would agree to me destroying the ceiling (one continuous ceiling from the kitchen (under the theater) through the family room and dining room and living room...

The ceilings (between the floors) are insulated for sound dampening... I'm just wanting to add a bit more in the theater itself.

Thanks...

I'm sure Brian will answer, but you should be able to use any rigid, flat material on top of the Green Glued floor to make the sandwich (Particle Board, OSB, Ply, MDF, etc.). It would just be screwed down over your current floor (with a thin layer of GG between).

we can't find particleboard here for ~the last year (just the melamine/painted shelf stuff). it's all OSB, ply, and MDF. and the wildest thing of all is that MDF is the cheapest of that lot.

what billwill said is exactly right. pick something of about the same thickness as the other layer (or a bit thicker), and that won't break the bank. Another layer of particleboard is a fine choice.

Brian...
Just reading this thread... a very exciting product. I'm putting together a spec for a new HT in the lower level of an existing home. We had planned to use homasote and decoupled drywall on both sides of a 2x4 wood stud wall for a STC value of 51 or better. ("Decoupled" per homasote's installation instructions of staggering the dryall edges, screwing drywall to homasote but not to the studs... not using resilient channel.)

I noticed you tested GG with homasote (440 sound barrier). Do you have any data that quantify:
a) the incremental benefit of homasote-GG-5/8gypsum versus homasote-5/8gypsum?
b) which is better... decoupled homasote and 5/8gypsum or GG and 2 layers of 5/8gypsum?

Thanks!

hey Tom,

the test we ran was for damping and wave speed in a drywall/gg/homasote/gg/drywall sandwich, which was what someone asked above. we found (in two tests) it to perform ~the same as drywall/gg/drywall/gg/drywall. the test we are

a) i wouldn't use soundboard + GG, i'd use 2 layers of drywall with GG. i would probably opt for 2 layers of drywall sans GG over drywall + soundboard as well. STC ratings can sometimes just mean a big problem moved just under 125hz, and nothing was really gained at all.
b) the latter. homasote has a damping factor of ~.04-.05, which is very high for a common building material, but 6-10x lower than drywall-gg-drywall, and...

the combo of GG + soundboard seems to interest alot of people, and we are working to find the ideal manner of use. we think these combinations are worth a look (and are trying some test walls, and may include one or two of these in our ind. lab test batch). the most intriguing is:

2 layers soundboard w/green glue then drywall on top (or a drywall/gg sandwich)

so soundboard/gg/soundboard then drywall or drywall/gg/drywall screwed to center of the soundboard sandwich. the presence of GG would raise the damping of the soundboard by an order of magnitude, and even over the 8-12" from the screw location to the studs, an immense amount of energy could be dissipated

Brian

i'd check with local code before not screwing drywall to the studs, BTW.

Brian,

A while back you mentioned in a post:

"i'll be back with another thought on the concrete + air cavity issue later this week"


Any further comment on this? I'm very close to starting the framing on my theater and two of my theater walls(front and left side) will be along concrete walls. I had intended to build these walls with a 1" gap between concrete and wall. I'm interested in what you found and have to say about using this type of wall construction.

Logan

hi logan, thanks for bringing that up. it would appear that i forgot to follow up later that week, eh?

i referenced some tests we were running on that type of resonance (concrete/air/drywall) and Green. To sum, using Green between sheets of drywall was very good, but adding green+something over the concrete didn't improve things enough to justify the cost for all but cost-no-object situations.

i.e.,
concrete/green/plywood/air/stud/drywall/green/drywall
was only marginally better than
concrete/air/stud/drywall/green/drywall

when you comment that you have a 1" gap between concrete and the wall, do you mean 1" between the back of the studs and the concrete or 1" between the back of the drywall on the concrete?

if it's a 2x4 frame + 1", that would leave the concrete ~4.5" away from the drywall - that's the important statistic here - concrete to drywall distance.

Brian

Originally posted by Brian Ravnaas
if it's a 2x4 frame + 1", that would leave the concrete ~4.5" away from the drywall - that's the important statistic here - concrete to drywall distance.
Brian
Hi Brian,
I'm interested in the concrete to drywall distance issue - I've got the same thing. 3 walls are concrete - 2 exterior & one long interior. For my exterior walls, I have 1" + 2x4 frame, for a total of 4.5" distance. My interior wall is more flush, for a total of 3.5". All walls will have fiberglass fill, the exterior will have 1" of air space, then 3'5" fiberglass (w/ a vapor barrier), then drywall+GG+drywall. The interior wall will have 3'5" fiberglass, then drywall+GG+drywall.

Does the concrete to drywall distance issue have to deal with resonance? Just yesterday I started doing fiberglass on the interior wall, I'm curious if my distances should change my approach.

Thanks!
Bob

hey Bob,

the air depth will affect the location of the resonance. the combination of the stiffness of the construction, the air cavity depth, and the weight of the drywall layers will determine the location of the resonance frequency.

it's usually good to drive those resonance frequencies down as low as possible.

the situation you describe will not cause problems in either case, proceed. :)

Brian

Originally posted by Brian Ravnaas
the situation you describe will not cause problems in either case, proceed. :)
Brian
phew - I had to shut down production, now I can start again. Of course it takes a couple of days to get all the equipment warmed up again:D

Brian,

Thanks for the quick reply. I will have 4.5" concrete to drywall and intend to build the same as Bob; concrete->1"gap->2x4->drywall->GG->drywall. The reason I brought this back up is same as Bob's. Resonance. Thanks for the insight.

Bob - at least you had your equipment running. I'm still trying to get mine to turn over and start for the first time. :D

Logan

Originally posted by elmn8r
....at least you had your equipment running. I'm still trying to get mine to turn over and start for the first time. :D
Logan
well the problem is I spend too much time on this forum and not enough in the basement!

This question may seem dumb, but can you use Green Glue in non-HT settings, say, like a master bedroom, where there is the stud then GG then drywall?
Could you do this without adding another layer of drywall, so basically you just put the GG on the studs facing the room, and then put the drywall (gg sandwiched between studs+drywall). I know the drywall wouldn't all be covered, but this way the only thing between the drywall and the stud is the green glue, so there would be some sound dampening. Is this approach good? bad? not feasible?
The only reason i am saying, is that I want to use green glue in my HT, however for soundproofing bedrooms, the builder just wants to put high density or high rating fiberglass insulation saying that will do the trick.
Let me know..thanks

- SR -

hey SR

great question - about using GG on only the studs. That's not much surface area, and it's in a fairly low-shear area, so the damping won't approach that of putting it over the whole sheets. But it will (i base this on internal tests) raise TL a few dB from the resonance region up. And since the surface area covered is so low, it's nearly free, and therefore i recommend it.

if you have a bedroom directly off the theater, i recommend more than just that, and how much isolation do you need in the bedrooms?

insulation isn't at it's most effective in normal 2x4 walls, because direct transmission from one side of the wall to the other via the studs lets most of the noise bypass the absorbing material.

Does the green glue retain its flexability over time? How long has the product been in testing?

hey Jneel, i'll answer in a second, but first a note about tech support since this is the Green Glue thread:

we have had some odd email behavior lately, and several messages have seemed to show up a day or so after they were sent. Also, i've gotten a few mails returned lately - some dating back weeks... i am very sorry if i haven't answered in a timely fashion someones query, we're doing the best that we can to figure out WTF is going on.

and never hesistate to just harass us about it. we mean well, and nobodies note has intentionally gone unanswered, so SEND IT AGAIN

:)

hey jneel, that's a great question, someone else had it up above in this thread as well.

GG is 100% modern synthetic polymers, it's not hydrocarbon elastomer material like neoprene, etc., it's not rubber, it's something else. Now the GG formulation has been around for ~ a year, and we've run what stability tests can be run during that time - like heat aging, etc., and have been very pleased with how it stacks up against laternate materials.

we have samples of similar resins that have aged in indoor out-of-light conditions for 15 years without degradation, and we've done what can be done to ensure even more stability. As i said above, the best way to know how something will be after 20 or 30 or 40 or 50 years is to wait 20...50 years, but considering the good quality of the composition and the extremely easy environment (no sun, no heat, etc.), it shouldn't be a concern. We've done what can be done to ensure that. :)

"but considering the good quality of the composition and the extremely easy environment (no sun, no heat, etc.), it shouldn't be a concern. We've done what can be done to ensure that. "

When you say "no heat", you mean extreme conditions or regular furnace indoor heat?

hey vitod, i mean industrial heat that would tend to acclerate aging. so extreme conditions.

for example, drywall is a nice material, probably won't fall off the walls, but it decomposes very rapidly with even mild "heat" of ~75-80C. with some amount of heat*time, it'll rever to plaster of paris (gypsum will). part of the great fire properties of gypsum board materials is that dehydration / reversion to plaster. The process of expelling the water molecule absorbs significant energy - that's called an endothermic reaction.

the most common flame retardant in use (i believe) is alumina trihydrate, or ATH, and it absorbs large amounts of heat / releases water as well to cool and smother fires. widely used in fire-retardant carpet backings, paints, and many other applications.

After reading this thread I'm very interested in this product, though my basement HT plan currently calls for a suspended ceiling. If I usd GG on the four walls, what could I use to treat the ceiling?

by suspended ceiling do you mean an absorptive tile ceiling? if so, and sound-isolation is a goal, using a drywall ceiling is a big start!

is that what's in the plan as of now? acoustic tile?

Yes, acoustic tile ceiling is currently my plan, though if I can see a compelling reason not to I'm willing to change my plan. I have quite a few plumbing shut off valves that I need to have accessible and I figured a suspended ceiling would be the eaiest way to accomplish that as well as making future wiring issues a lot easier.

The acoustic tile ceiling will limit low frequency isolation via the ceiling path, and whatever flanking paths relate to the ceiling. A flanking path would be noise going to the next room via the ceiling/structure/etc.

a drywall ceiling will be better at most frequencies, and an improved drywall ceiling - like one hung on RSIC clips or damped or channel or whatever, will be better still.

Rynberg of this forum mentioned a product that is acoustic tile with drywall in a sandwich, perhaps that is a useful compromise (much heavier).

perhaps you could make part of the ceiling removable via panels of some type?

but i do think that you should contemplate a bit the need for isolation, and how much the limited performance of that ceiling will limit that.

treating the floor from beneath with Green is a great idea if you must have the tile ceiling. that will do alot to limit flanking sound.

Brian

Hi,

I am finishing out our basement and putting in a media room (not a dedicated HT, unfortunately). The front and left side wall is cinderblock, the back of the theater is 22' from the front wall and is marked by columns, the kids play area is directly behind the columns, the actual back wall of the room is 38' from the front wall so the kids area is 16' deep. The right wall is basically a wall that has an opening for the eq rack and then a long double door closet. I am not terribly concerned with sound isolation since the sleeping quarters are two levels above but i am concerned with sound quality. Does double drywall with gc make sense in this situation and if so where would you use it. Also if I am planning on using insul shield on the dry wall (either single or double) would you use gc between the insul shield and the top dry wall layer? Thanks Ron

Hey Ron,

This is a fantastic question. Maybe it would be helpful if some of the AVS members who have/are working with green chimed in. Most of them aren't finished with their rooms, i don't think. But a couple of gents from this forum have commented that it cleared up "echos" in their room (one of their words), etc. if they see this, perhaps they will comment.

I will answer this with what i know, as i know it.

it'll eliminate or at least grossly reduce the chance of the wall rattling. it will improve sound transmission, blah blah blah


My understanding of the impact of Green Glue on in-room absorption is somewhat different. I would anticipate that the absorption of a common wall would ahve two traits

1. it would be fairly narrow in band
2. it would ring (re-radiate some sound back inot the room after the music stopped)

Green glue would (this is my thoughts) flatten and broaden the absorption curve, and it will 110,000% wholly eliminate ringing. But i don't think it will raise the peak absorption of the wall.

anyone is welcome to chip in.

Now, i am not nearly as competent to discuss room acoustics as Noral Stewart who is a very noteworthy acoustics professional. see here: http://www.stewartacousticalconsultants.com/people.html

in this thraed: http://groups-beta.google.com/group/alt.sci.physics.acoustics/browse_frm/thread/d10d829078db658c?hl=en&lr=&ie=UTF-8&newwindow=1&safe=off&rnum=1&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DUTF-8%26newwindow%3D1%26safe%3Doff%26selm%3D9bhbtf%2524cap%25241 %2540slb5.atl.mindspring.net

he enters this comment about damped walls in this regard: "In theory and concept it should provide some benefit as claimed. Light gypsum walls do vibrate and absorb some energy in doing so. In concept, the material improves this ability to absorb energy and reduces the chances of any of that energy being re-radiated."

so perhaps my understanding needs a tweaking.



another thing that is interesting to measure, although i don't know what it means for the sound in a room, is the tendency for walls, ceilings, etc. to vibrate (sometimes strongly) at their resonant frequencies even when no noise is being played at those frequencies.

in loudspeaker cabinets this is called "wolf-tone" behavior.

we did a study in one room, on the walls and ceiling, and found that this wolf-tone behavior spanned about one octave. The ceiling had a primary structural resonance at an average of 172hz.

noise between 100 and 250hz caused the ceiling to vibrate at 172hz (average, again). For about 1/2 octave, the ceiling vibrate dmore at 172 hz than at, say, 157hz or 198 hz.

interesting, and i don't know what any of this means.


whatever the case, this is something that we will study when time allows, and attemp tto offer predictions of absorption for Green walls of various configurations.

take care,

Brian

I wrote in another forum that once my walls were up with "Green-in-Between" (What is my kickback for providing you your slogan?) I had less echo. Basically, when I clapped my hand within the various rooms in my basement, the bathroom and HT had the least amount of slap echo. Remember that there is only a concrete floor, no pad or carpet yet. The bathroom probably had less echo due to the fact it had less parallel surfaces with the tub, shelves, and closet. The HT is almost exactly the same configuration as another room, but it has less echo. The echo dies much faster. I don't have any measurements or recordings to prove this, but even my non-audiophile wife could tell the difference. I can also say there is MUCH less impact sound from the family room above it. I can't say this is just because of Green since I have quite a bit of layers there. The joists were filled with R-19 insulation, then a layer of sound board (with Green where the joists were), then 5/8 drywall, Green Glue, then 5/8 drywall. I will have to wait to install the door prior to telling you about the reduction in sound transition.

hey Bruno, that is pretty catchy!

the echo - was that low frequency echo or pingy echo...?

It was slap echo that fairly low to mid fequency. I am sure someone could tell us the typical frequencies for a hand slap. Obviously there is an echo still present since you would never get rid of the first reflections, but it certainly dies down faster.

that's very interesting. I do think this is something worth exploring, as that's at least the 3rd similar feedback i've recieved. curse my lack of in-room absorption expertise

;)

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.

Peter, I noticed on your theater that you installed a layer of plywood and then two layers of drywall. Did you put Green Glue between the plywood and first layer of drywall, or is it just between the two layers of drywall? Your theater is the first one I've seen with the plywood layer. Was this for additional sound proofing or was there another reason for it? If it was for sound proofing, do you think it was worth the additional cost for the results you acheived? I'm working on the design of my HT and I'm wondering if I should add the plywood with an additional layer of Green Glue between it and the first layer of drywall.

(By the way, every time I see one of your posts, I can't help myself but go look at your HT again. It still inspires me!)

First, thanks for the kind words about the theater.

Second, the plywood is there for the resilient channel system. It was recommended tha this be attached to the plywood. The Green Glue is best between two layers of drywall, ergo the reasoning.

However, if you are not using a resilient channel system, then I would drop the plywood and simply go with two layers of 5/8" drywall.

Hope that helps.

I am getting close tho the drywall stage of the HT project. Studs are up and electric is being installed.
Next is drywall.
I am doing double wall construction with two layers of drywall. (5/8 bottom and 1/2 inch top.) I am thinking about going with GG, but my original plans were to just use liquid nails in between the drywall layers and screws. Do you/can you use both methods at the same time or is this a no-no?

Craig :)

Originally posted by suffolk112000
I am getting close tho the drywall stage of the HT project. Studs are up and electric is being installed.
Next is drywall.
I am doing double wall construction with two layers of drywall. (5/8 bottom and 1/2 inch top.) I am thinking about going with GG, but my original plans were to just use liquid nails in between the drywall layers and screws. Do you/can you use both methods at the same time or is this a no-no?

Craig :)

Do you mean put both Liquid nails AND Green Glue in the same layer?

I'm pretty sure this would be a bad idea.

Liquid nails will bond two sheets of drywall into a single ridgid layer--basically making it one sheet of drywall.

Green Glue is flexible, and allows both sheets to sheer against each other.

Originally posted by Toeside
Do you mean put both Liquid nails AND Green Glue in the same layer?

I'm pretty sure this would be a bad idea.

Liquid nails will bond two sheets of drywall into a single ridgid layer--basically making it one sheet of drywall.

Green Glue is flexible, and allows both sheets to sheer against each other.

Toeside,

Yes... the same layer. Common sense was telling me that it was a bad idea to not use the two together, but hey... you never know.
So, if I use GG, I should not use any caulk at all when drywalling.. ??
Not even between the studs and first layer of drywall... ??

My theater is going to be 18.5 X 22.5 with an average ceiling height of 8.5 feet
If I go with GG, how much of this stuff am I going to need to buy?

Craig

Originally posted by suffolk112000
Toeside,

Yes... the same layer. Common sense was telling me that it was a bad idea to not use the two together, but hey... you never know.
So, if I use GG, I should not use any caulk at all when drywalling.. ??
Not even between the studs and first layer of drywall... ??

My theater is going to be 18.5 X 22.5 with an average ceiling height of 8.5 feet
If I go with GG, how much of this stuff am I going to need to buy?

Craig

If you are planning on using Green all all 4 walls and ceiling, that's about 1113 sq ft, or 18.5 Gallons of Green. Remember, Green is advertised to be 75% effective at 50% coverage.

Luckily, my project includes both sides of a double wall (one side vaulted to 12 ft, the other side is 8ft), plus another 16x8 wall. I figure I can do all this at just over 50% coverage--my budget allows for only one 5 gallon bucket of Green. :(

Oh yeah, about whether to caulk or not... Liquid Nails get's rock hard, caulk doesn't. Several people are using acoustic caulk in their drywall seams and electrical boxes. One person, might have even been mentioned in this thread, said he was going to use green between the framing and the first layer of drywall.

Originally posted by Toeside
If you are planning on using Green all all 4 walls and ceiling, that's about 1113 sq ft, or 18.5 Gallons of Green. Remember, Green is advertised to be 75% effective at 50% coverage.

Luckily, my project includes both sides of a double wall (one side vaulted to 12 ft, the other side is 8ft), plus another 16x8 wall. I figure I can do all this at just over 50% coverage--my budget allows for only one 5 gallon bucket of Green. :(

Hmmm... $1000 for GG.
I will have to pass. :(
Thanks for the reply.

Craig

Originally posted by suffolk112000
Hmmm... $1000 for GG.
I will have to pass. :(
Thanks for the reply.

Craig

I just ordered mine yesterday. I ended up getting enough to do the floor too... I think the total was $510 with shipping. What's crazy is total materials for my project is around $1900. $510 of that is Green Glue, $380 is the door. 1/2 of the budget is gone right there.

Brian,

Have you done your attenuation through the wall vs. frequency measurments yet?

Also, my theater will have a blueboard-homasote-blueboard stackup. If layer 1 is the layer that attaches to the studs, I'm planning to use Green Glue between layers 2 and 3. If you measure a significant improvement with Green Glue between both 1 & 2 and 2 & 3, Ill do that too.

hey guys, liquid nails and Green Glue could be used in combination if you put the liquid nails in a specific pattern to avoid interfering with the necessary shear.

but that wouldn't really be worth the bother

i think most people who are building new walls and using green have put it between the drywall and the studs, no?

Now, if you used 50% coverage with GG, you'd wind up with (in theory) 120sq feet/gallon, so about 2 pails. It's up to you to make sure you meet your coverage goals, of course. I suppose it depends on what type of liquid nails you opt for, but it would cost maybe 12-25 dollars a gallon? around there? might be interesting to calculate the cost difference of green to a common adhesive, maybe someday.

Brian

hey Ken,

our time in the labs is nearly here, the measurements should not be far off.

I would offer that using 1/2 coverage of Green between twice, rather than full coverage once and none once is another option.

what is blueboard?

Brian

also, Ken, homasote is generally recommended as the inside layer, and then you screw the next layers into it. so it can act as a resilient de-coupler of sorts.

as a central layer, i wouldn't recommend it over just a sheet of drywall. The drywall is heavier, which is a good thing.

Brian

I am retrofitting an existing space. Any areas of all new wall construction will get GG on stud surfaces. My one test panel of a single layer of drywall with GG between it and the studs, showed a noticeable improvement over the existing prehung drywall (no GG). I figure it won't use much GG, but it is fussy enough work applying GG to the studs that I have considered buying another trowel, and cutting it down to putty knife size. All new wall sections I build, that will be common to the rest of the house, will get GG on stud. Ditto for the ceiling.

Blueboard is regular drywall with a waterproof coating (which happens to be blue). Our architect specified it.

http://www.bobvila.com/ArticleLibrary/Task/Building/Blueboard.html

hey Tedd, that's a great idea. i know a place that sells stud-sized trowels, and i will request that audio alloy begin shipping them with orders upon request to accomodate this use (studs), as big trowels ARE a PITA.

that's cool feedback as well.

Ken,

is the blueboard literally waterproof/airtight? if so the central layer of your 3 item sandwich should be something that isn't, like regular drywall (which i'd still recommend over homasote). i LIKE homasote+homasote with green glue, but we get better results here with drywall+ drywall than homasote+drywall if they are to be used as a sandwich ala your description.

now, homasote/homasote damped + drywall/drywall damped used in the normal manner has just marvelous potential, but that's a bit different than your application.

Richard Bird at Rives Audio specified that stackup. I'll have to ask him about it. They have done quite a few high end theaters, so presumably experience has led to this configuration.

Thanks

Trust me, you won't need no stinkin liquid nail.

:D

I'd dropped into this thread back in November, but had to put my HT upgrades on hold until my furniture actually arrived.

Now, I am once again ready to tackle this project!


My need, is to build a wall that is as thin as possible, while being as effective as possible, across the back of my theater. It will be in the position of the crude green line in the picture below (yes, I'd rather do double doors, to make the area as open as possible when not "in use" - and I've checked out threads here about using heavy outside doors, etc).

http://www.goglen.com/post/theater3.jpg

The reason I need it thin - is that the sofa needs to be as far back as possible, to give it room to recline (the 1st row position is set - large Berkline 099's that need to be in line with the side speakers.

So, what would be the best way?

I'm currently thinking: (outside to inside)
Sheetrock
GG over studs
studs (with insulation between)
GG
sheetrock
GG
sheetrock

Given this, would it be feasible to use the studs as 4x2's instead of 2x4's -- in other words, have the cavity between the outside and in only 2" instead of 4"?

Would I achieve any noticable advantage if I did another layer of GG and sheetrock on the outside wall (ie, so both inside and outside walls are a sheetrock/GG/sheetrock sandwich)

This outside wall is important - as it is needed to block the sound from the bedrooms and large open staircase (where the downstairs kitchen and family room are open to the bottom of the stairs).

Thanks...

Brian:

now, homasote/homasote damped + drywall/drywall damped used in the normal manner has just marvelous potential
Would you elaborate on that please? :)
How would
{hemasote + GG + hemasote + drywall + GG + drywall}
compare to
{drywall + GG + drywall + drywall + GG + drywall}
compare to
{drywall + GG + drywall + GG + drywall}
as a wall layer.

Glen, 2x4's used as 4 wide and 2" deep ( 3 1/2" by 1 1/2" actually) will not give you anywhere to run electrical wire, unless the cable is armoured. I imagine your local code will require outlets in the new wall, and the depth is not there for them either. I also expect studs used in that manner will warp and give you a "wavey" wall. If that hallway is wide enough, you could pull the theater wall back abit.

Hey Brian R., you guys at AA should make GG in a tube for caulking guns. Then all you'd have to do would be to run a 1/2" bead on each stud/joist and hang the drywall.

Originally posted by Fatman513
Hey Brian R., you guys at AA should make GG in a tube for caulking guns. Then all you'd have to do would be to run a 1/2" bead on each stud/joist and hang the drywall.

Wow, that's a good idea!

Originally posted by BasementBob
Brian:


Would you elaborate on that please? :)
How would
{hemasote + GG + hemasote + drywall + GG + drywall}
compare to
{drywall + GG + drywall + drywall + GG + drywall}
compare to
{drywall + GG + drywall + GG + drywall}
as a wall layer.

Hey bob, you raise a great question. And one that is on the to-test list, but hasn't gotten done yet. Any of those walls would be heavy, low-resonance walls, but it's the apparent legality of being able to screw drywall into the homasote that intrigues me.

see, with damping materials energy is destroyed over distance. And that might seem quasi-trivial when studs are 16" or 24" apart (easier to visualize, perhaps, on a staggered stud wall where the distance to th eplate is larger). But when damping reaches high levels like 20-35% of critical damping, decay rates get immense.

The homasote does two things here. 1) allows drywall to not be fastened to the studs 2) modest bending wave speed

so by screwing into the homasote, you create a much larger path, also part of that path will have slower wave speed, and ...

i conject that one may be able to attain a level of performance with this construction that is unique for a thin, single stud wall.

>side note< via calculation of bending wave speed for a GG damped 1/2" drywall sandwich with critical frequency @ 2500hz and damping on par with the tests we've run on production material over the last time here, the predicted decay rate over distance is ~~~~~ 50+ dB/meter at 1khz. Even at 100hz it remains ~24dB/meter. And the path length in this case becomes very long when you consider the (i think/ponder/theorize) complex reflecting / partial transfer through the mechanical elements nature of vibration moving from drywall to stud and then to the other side.

but, then, i wager a surprise or two is in store for a normal construction as well.

:)

i want to add a technical note to my last commentary. Those number - 55db/meter of energy decay - seem out of control, let's just say. So part of this is the background math and part is an explanation of why (once we figure out how to measure this with more confidence, the numbers on audio alloys site are conservative to a considerably degree). PITA factor in testing this, skip long story here.

But, for example, we have run simple (4-11 data points) damping tests on every batch of Green that the plant has produced. I have here the reports for the last 7 in my study, and taking an average of these values we have

100hz = 0.57 = 28.5% of critical damping (not an official spec,)

with a calculated critical frqeuency of ~2500hz for a 1/2" drywall sandwich, this leads to an estimated bending wave speed of 70m/sec @100hz. With damping=0.57 that correlates to 22db/meter of decay.

at a frequency barely above subwoofer territory. and that's pretty neat.

This is all informal data, only for discussion purposes here.

but now let's say that rather than ~50db/meter, the actual decay was 40db/meter or whatever at 1000hz.

a reason that this figure might be lower is the transfer of energy over distance in the form of quasi-longitudinal waves. These waves are not important for the transfer of sound in the normal models, but they are very efficient at transferring energy from point A to point B.

but they cannot generate sound - these vibrations do not generate sound on the other side of the panel.

but again, the presence of energy at point B may lead to the bending waves that do re-create sound in this great process somewhere at a greater distance.

end that disclaiming pile of jabber

Originally posted by Fatman513
Hey Brian R., you guys at AA should make GG in a tube for caulking guns. Then all you'd have to do would be to run a 1/2" bead on each stud/joist and hang the drywall.

This will come to pass, it will it will. :)

Originally posted by kwolff
Richard Bird at Rives Audio specified that stackup. I'll have to ask him about it. They have done quite a few high end theaters, so presumably experience has led to this configuration.

Thanks

Hey again Ken,

I checked out Rives web site, very nice. The recommendation of drywall/soundboard/drywall may be related to damping of the panels. Drywall has essentially no internal damping, with a damping factor of about .004 to .008, or only a fraction of a percent of critical damping.

Homasote has damping of ~.05, which is the highest (i assume other soundboards are similar, i mean this fiberboard/soundboard type of stuff is the highest) of any common construction material that i'm aware of. The semi-compressible very rough surface of the stuff may further improve damping via friction effect between the layers. i don't know, it seems reasonable.

If homasote is associated with some improvement in such a sandwich due to damping, this is not applicable to a green glue wall as the GG will supply 99+% of the damping, and to maximize this aspect of performance, one should work to optimize the use of gg, and forget other factors.

And soundboard has a PHENOMENAL name - soundboard - and 4 decades of strong marketing to back it and push it into the minds of people for this (and other) applications. Indeed organizations above and beyond the companies have labored intensively over the years to find ways to use this stuff in these applications, and it has probably been the beneficiary of many hundreds of lab tests worth ... millions, i suppose, of R&D dollars.

It's not magical stuff. It's flexible, it has less severe resonant behavior than other materials, it's usually tested in wall configurations that drive the low frequency resonance (it's flexibility helps here) below the 125hz STC cutoff, and it's usually marketed around STC (which rewards you handsomely for pushing problems below 125hz).

those are my thoughts, i have no doubt that Rives is emminently competent. And i have no doubt that GG will outperform soundboard and will perform better with all-drywall save perhaps as i discussed above in reply to basementbob.

take care,

Brian

Originally posted by Glen Graham
I'd dropped into this thread back in November, but had to put my HT upgrades on hold until my furniture actually arrived.

Now, I am once again ready to tackle this project!


My need, is to build a wall that is as thin as possible, while being as effective as possible, across the back of my theater. It will be in the position of the crude green line in the picture below (yes, I'd rather do double doors, to make the area as open as possible when not "in use" - and I've checked out threads here about using heavy outside doors, etc).

http://www.goglen.com/post/theater3.jpg

The reason I need it thin - is that the sofa needs to be as far back as possible, to give it room to recline (the 1st row position is set - large Berkline 099's that need to be in line with the side speakers.

So, what would be the best way?

I'm currently thinking: (outside to inside)
Sheetrock
GG over studs
studs (with insulation between)
GG
sheetrock
GG
sheetrock

Given this, would it be feasible to use the studs as 4x2's instead of 2x4's -- in other words, have the cavity between the outside and in only 2" instead of 4"?

Would I achieve any noticable advantage if I did another layer of GG and sheetrock on the outside wall (ie, so both inside and outside walls are a sheetrock/GG/sheetrock sandwich)

This outside wall is important - as it is needed to block the sound from the bedrooms and large open staircase (where the downstairs kitchen and family room are open to the bottom of the stairs).

Thanks...

the utilization of non load-bearing steel studs comes to mind for the thin wall with high performance. the 2.5" type (65mm, however you find them).

Before i offer that as a formal recommendation, allow several more days for an in-progress exploration of this in our labs for an industrial application. I will comment then on the impact that GG has on the low frequency behavior of this type of wall. Which is not good normally. Steel studs like RC on common 2x4 walls yield high STC but ... probably unaccpetable sub-region performance for this application.


WRT using green on both sides -vs- 1. Yes, you will gain quite a bit. VERY ROUGH estimate only here, about 60%/40% of the gains for upgrading the two sides. you can use 50% green on both sides and this WILL 100% outpeform 100% green on one side, and will keep the gg component of costs the same. i know that installing the drywall may well be more expensive than the extra gg, but i guess i can't do much to help with that one.

perhaps others can offer better thoughts on the non-sound-isolation ramifications of using the thinner wall. it won't help...

now, the doors will likely be the weak link over most of the frequency range. put alot of care into those, as even the greatest wall in the world can fail if it has two shoddily sealed/made/selected double doors right smack in the middle.

good luck and post again if you need more of my pennies

Brian

Originally posted by markfh
Trust me, you won't need no stinkin liquid nail.

:D

ah, but if the days get too long, maybe that stink can be put to good use?????????????????

did i say that out loud?

anyway, it's worth adding that over some frequency range in the sub region on a normal 2x4 wall, mass will be a/the defining factor. And the 4 layers of drywall that bob commented about are heavier.

Brian what if a person was to sandwich your green glue between 2 sheets of 703 fiberglass and mounted it on a door. Would this be an effective means blocking sound without being to heavy for an enterior door. Sorry in advance if this is a stupid question, how about if I plead the 4:30 am punch drunk insanity defense?

Originally posted by dynamowhum
Brian what if a person was to sandwich your green glue between 2 sheets of 703 fiberglass and mounted it on a door. Would this be an effective means blocking sound without being to heavy for an enterior door. Sorry in advance if this is a stupid question, how about if I plead the 4:30 am punch drunk insanity defense?

Brian has to sleep sometime (I think?!), so if he doesn't mind, I'll give you an answer. A damping material like Green Glue would have no affect as a sandwich between layers of semi-rigid fiberglass. Because fiberglass is very light, flexible, and internally absorbent of energy, it bends freely without resonating. So there are no resonances in it to dampen.

- Terry

Originally posted by Terry Montlick
Brian has to sleep sometime (I think?!), so if he doesn't mind, I'll give you an answer. A damping material like Green Glue would have no affect as a sandwich between layers of semi-rigid fiberglass. Because fiberglass is very light, flexible, and internally absorbent of energy, it bends freely without resonating. So there are no resonances in it to dampen.

- Terry

Would adding an OC 703 panel to doors help at all?

Originally posted by Toeside
Would adding an OC 703 panel to doors help at all?

Not for sound isolation.

- Terry

hey terry, since you're around these parts...

in your opinion/experience, is there a substantial possibility of FRK-faced 703 or 705 to exhibit resonant panel behavior?

about the FRK - i'm just curious because i've seen considerable discussion about this on other forums. - about FRK panels exhibiting resonant behavior that wouldn't be seen with non-faced panels.

Originally posted by Brian Ravnaas
hey terry, since you're around these parts...

in your opinion/experience, is there a substantial possibility of FRK-faced 703 or 705 to exhibit resonant panel behavior?

Hi Brian,

I've never done any testing for such resonance of FRK-faced fiberglass. But Kraft paper is pretty heavy -- I'm guessing a typical paper density of approx. 1000 kg/m^3 and a nominal thickness of 7 mils. The foil layer, though even denser, can probably be ignored because of its extreme thinness.

The predicted panel resonance (plugging these numbers into our proprietary impedance transfer matrix model, which assumes infinite extent of panel, of course ;) ) is about 400 Hz for 2" 703 plus a 2" airspace. And the absorption coefficient is predicted to be a little over 0.9, with a Q of around 2. So I think there is no reason to believe that panel resonance wouldn't be a significant effect.

- Terry

Thanks Terry and Brian you both are a world of information.

I have gotten word from one of my partners in crime here in the lab that Green fire test results are back.

per the appropriate standards and regulations, the dried Green's flammability was assessed. It passed with flying colors, recieving a score several times better than necessary.

so if fire is on any Green customers mind, this is a very good thing.

Does this mean I need to talk to by building inspector to see if this is acceptable?

i don't understand, i don't think, ken.

the fire tests passed with considerable headroom coming within a few points of drywall for flammability. So, no, my post immediately above is not grounds for this at all.

Originally posted by Brian Ravnaas
i don't understand, i don't think, ken.

the fire tests passed with considerable headroom coming within a few points of drywall for flammability. So, no, my post immediately above is not grounds for this at all.

Perhaps there's confusion in this statement:


it's score was several to many times lower than what was allowable to maintain the fire rating of the wall


Is lower better?

oh, i do apologize to all.

yes, lower is better. in this case lower=less smoke, fire, etc.

my bad, and i do apologize.

Originally posted by Brian Ravnaas
oh, i do apologize to all.

yes, lower is better. in this case lower=less smoke, fire, etc.

my bad, and i do apologize.


Phewww. After just ordering 10 gallons, I was worried, but was going to use it anyway. :p

But, nothing to worry about.

oh, heck, see edit above. passed with flying colors.

Originally posted by Brian Ravnaas
oh, heck, see edit above. passed with flying colors.

So much for your goal to NOT have misunderstood posts, huh?

Soon enough, the regulars will understand which numbers should be low, which should be high, etc.

But then the newbies will enter...and start the cycle all over again. :)

no kidding. i think i won't mention this incident again after today.

hee hee

no kidding. i think i won't mention this incident again after today.

on a similar note, last week i emailed a guy from another company who sells product to this kind of market and said "I saw a review of your stuff and it DOESN'T sound like you have a good product" (the review was very good)

?????????????????????????????????

Brian... can you direct us to the review?

If using green between 2 layers of 5/8, but not between the studs and the first layer of drywall is it better to:

A) Use only screws

or

B) Use both screws and conventional drywall adhesive

I was thinking option A would provide less coupling, but B would provide a better air seal.

Also for those that have applied GG to the studs what application technique/tool seemed to work best?

hey mmm,

do you mean using drywall adhesive between the studs and the drywall, or in between drywalls in addition to the gg?

if the latter, don't bother. If the former, drywall adhesive costs 1/2 of what gg does, and the cost of coating the studs is very small (small surface area), so i'd recommend using GG in all those nooks. If this throws off your plan for X number of pails, call audio alloy and something will get worked out so you don't have to waste a bunch of green/money.

backdoor, if you mean the fire review, you can sure have a copy when i get one. if you mean the product review, that was someone elses product. :) no mag reviews of gg that i'm aware of

Brian,

The question above related to between the studs and the drywall. I am definatly using GG alone between the two layers of 5/8.

The question came up because, based on some of the previous posts, it sounded like it could be a pain to apply GG to the thin edge of stud since it comes in a bucket rather than a caulk tube and I was wondering what the recommended attachment method for the first layer of 5/8 should be given that it will be followed by GG and another layer of 5/8.

Example:

Optimal= Stud > GG > 5/8 (Screwed) > GG > 5/8 (Screwed)

Next best option is A or B?
A) Stud > Nothing > 5/8 (Screwed) > GG > 5/8 (Screwed)
B) Stud > Conventional Drywall Adhesive > 5/8 (Screwed) > GG > 5/8
(Screwed)

Sorry if my first post was confusing.

I haven't ordered my GG yet (I will in a week or two...promise). But what I was planning on doing in order to apply it to the studs was to cut the corner off a gallon size Ziplock bag and use it like a mortar bag. Is the viscosity of GG such that a method like that would be feasible?

Originally posted by mmmkam
Brian,

The question above related to between the studs and the drywall. I am definatly using GG alone between the two layers of 5/8.

The question came up because, based on some of the previous posts, it sounded like it could be a pain to apply GG to the thin edge of stud since it comes in a bucket rather than a caulk tube and I was wondering what the recommended attachment method for the first layer of 5/8 should be given that it will be followed by GG and another layer of 5/8.

Example:

Optimal= Stud > GG > 5/8 (Screwed) > GG > 5/8 (Screwed)

Next best option is A or B?
A) Stud > Nothing > 5/8 (Screwed) > GG > 5/8 (Screwed)
B) Stud > Conventional Drywall Adhesive > 5/8 (Screwed) > GG > 5/8
(Screwed)

Sorry if my first post was confusing.

According to Dennis you should use an adhesive over nothing be it Stud Adhesive or GG. There is a possability of the drywall vibrating against the studs without adhering it to the stud face.

John

Thanks john thats exactly the info I was looking for.

IRT everyone who is concerned with how to apply to a stud face.....

I too was wondering about that, even posed the question of getting a cake icing bag from a cooking store.

Well I can tell you, as I have 2 buckets in my basement, I cracked one open to use a little for some soffit framing where the frame touched the ductwork. Here are my oberservations:

The stuff is thick AND gooey. (to me, it's kinda a cross between vinyl flooring glue and liquid nails thickness) I don't think I would want to mess with trying to load it into bags. I think the least amount of touching you have to do to the stuff, the better off you are.

My plan now is to get a plastic drywall mud "trough" (those ones you use for mud and tape - 12" x 4" x 4" and cheap to throw away when done) and a big spatula and scoop it out into the trough and use the supplied trowel to "butter" the GG onto the stud face, working perpendicular to the long axis. I don't think it will take very long at all that way.

I had the same thought about using the 12"x4"x4" trough to get it on there. Let us know how it works out. I also thought about getting a cheap 2" putty knife and cutting some notches in the blade to scrape off excess like a small notched trowel.