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Discussion Starter #1
I need to make a decision tonight.. I have a case of green glue on rush delivery set to arrive tomorrow morning.... I WAS going to go with Roxul 24" OC insulation - I've got 2x6 top and bottom plates I'm going to have 2 layers of 5/8 drywall overtop of that with green glue. My contractor said that nowhere has the 24" OC Roxul, only 16" - I understand that green glue is not recommended for 16" OC.... My question is: Do I go with R13 or R19 insulation? My contractor is insisting on R19 - but I want to know what's best... He also acted like "no one builds on 24" OC and that is why he didn't see 24" OC Roxul in the stores. So Should I tell him to use R13 or R19 insulation with the 24" OC stud wall? Please respond ASAP if possible as the job is being completed tomorrow morning.
 

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I'm not quite following what you're asking. If there is 3.5" of space in the wall (depth), use R13. If there is 5.5" user R19. I'm confused because you said the top/bottom plates are 2x6, but the studs are 2x4. Is this a staggered stud scenario? If so, I'm guessing you would want to use R19 in a width that fits between each stud. Anyway...sorry, I'm just confused about the width question alongside the R-value question. How does one have to do with the other? If you clarify maybe someone can help better (and of course I'll try, but I'm no expert).
 

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Just use the pink stuff - real any number of threads here that the Roxul doesn't do much for us in home theater applications (meaning, equivalent performance to the cheaper pink stuff). Search here in the forum for performance of R13 vs R19, but I don't think it will matter which you use. With 24" OC the R19 might stay in place better, though...


Jeff
 

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Just use the pink stuff - real any number of threads here that the Roxul doesn't do much for us in home theater applications (meaning, equivalent performance to the cheaper pink stuff). Search here in the forum for performance of R13 vs R19, but I don't think it will matter which you use. With 24" OC the R19 might stay in place better, though...


Jeff
Oh ya...and this. Good advice.
 

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Discussion Starter #5
Just use the pink stuff - real any number of threads here that the Roxul doesn't do much for us in home theater applications (meaning, equivalent performance to the cheaper pink stuff). Search here in the forum for performance of R13 vs R19, but I don't think it will matter which you use. With 24" OC the R19 might stay in place better, though...


Jeff

I have no choice but to go with the pink stuff really, as I want to use 24" OC to get the most effect out of the green glue. I was just wondering R13 vs R19 based on thickness... Wondering if the less thick R13 will provide an air gap that will actually help with soundproofing performance.
 

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Discussion Starter #6
I'm not quite following what you're asking. If there is 3.5" of space in the wall (depth), use R13. If there is 5.5" user R19. I'm confused because you said the top/bottom plates are 2x6, but the studs are 2x4. Is this a staggered stud scenario? If so, I'm guessing you would want to use R19 in a width that fits between each stud. Anyway...sorry, I'm just confused about the width question alongside the R-value question. How does one have to do with the other? If you clarify maybe someone can help better (and of course I'll try, but I'm no expert).
Top and bottom plates are 2x6 so the depth of the wall is 5.5" - studs are going to be 24" OC - so I was wondering if using the R13 which would fill less of that 5.5" depth and leave an air gap would actually HELP the aspect of the soundproofing (I believe I have read things like this on this forum) - OR use the R19 - would fill the depth more, but not give as much of a dead air cavity space.... That's what I'm trying to figure out now.
 

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Ah...okay. I think I was confused by you saying 2x4 stud in the title. I'm guessing the studs are 2x6, then, to match the plates? If so, just use R19. Having air in the wall, as far as I can tell, has not proven to help with sound-proofing. Roxul or pink fluffy, or whatever, doesn't do much...it just keeps sound from resonating (thus creating weird noises) in the open spaces inside of various boxes near your room (including walls). Mass, physical decoupling, and damping are what help with sound isolation. I wouldn't worry too much about over-thinking this part...just fill the space, which in your case is R19. Good luck. Exciting times...the beginning of the project.
 

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Discussion Starter #8
Ah...okay. I think I was confused by you saying 2x4 stud in the title. I'm guessing the studs are 2x6, then, to match the plates? If so, just use R19. Having air in the wall, as far as I can tell, has not proven to help with sound-proofing. Roxul or pink fluffy, or whatever, doesn't do much...it just keeps sound from resonating (thus creating weird noises) in the open spaces inside of various boxes near your room (including walls). Mass, physical decoupling, and damping are what help with sound isolation. I wouldn't worry too much about over-thinking this part...just fill the space, which in your case is R19. Good luck. Exciting times...the beginning of the project.
I was dealing with the task of education my construction guy I hired too! haha... Yes, it is exciting... Just got the whole ceiling replaced due to leak/water damage (put a new roof on my home last week to eliminate the ceiling leaks)... So now the wall is getting 2x6 plates, 24" OC studs, R19 insulation + 2 layers of 5/8" drywall with green glue on the second layer (2 tubes per sheet of drywall).
 

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What is green glue? Haven't heard that term before, I assume it is some brand of construction adhesive. 16" O.C. is most common in the US. I'm sure you can get the 24" wide roxul or "pink stuff" but it might take awhile because as your contractor said it is not commonly used. If your in a hurry, your going to have to stick with more readily available materials. If the wall is an exterior wall, I would definitely fill the cavity with insulation with no airspace. If an exterior wall you may need a vapor barrier depending on your location in the US (your contractor should be familiar). If interior wall, more insulation should deaden the wall better than less (and you don't need to worry about the vapor barrier). Plus if you don't fill the cavity the insulation can sag in the wall. You can also use metal resilient furring channels placed horizontally to better deaden the wall and add an extra layer of gypsum board (which it sounds like you are doing). Also go with the 5/8" thick gypsum board (drywall) over the 1/2" thick gypsum board. It is a common detail. You can go to USG.com and they should have some typical wall assemblies with STC ratings (sound ratings) if your curious on the performance differences.
 

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What is green glue? Haven't heard that term before, I assume it is some brand of construction adhesive. 16" O.C. is most common in the US. I'm sure you can get the 24" wide roxul or "pink stuff" but it might take awhile because as your contractor said it is not commonly used. If your in a hurry, your going to have to stick with more readily available materials. If the wall is an exterior wall, I would definitely fill the cavity with insulation with no airspace. If an exterior wall you may need a vapor barrier depending on your location in the US (your contractor should be familiar). If interior wall, more insulation should deaden the wall better than less (and you don't need to worry about the vapor barrier). Plus if you don't fill the cavity the insulation can sag in the wall. You can also use metal resilient furring channels placed horizontally to better deaden the wall and add an extra layer of gypsum board (which it sounds like you are doing). Also go with the 5/8" thick gypsum board (drywall) over the 1/2" thick gypsum board. It is a common detail. You can go to USG.com and they should have some typical wall assemblies with STC ratings (sound ratings) if your curious on the performance differences.
Green Glue is used on tons of builds in this forum. It's used between 2 rigid materials such as two pieces of drywall to reduce sound vibrations. The collective thought on this forum is to avoid resilient channel (high chance of failure rate) and use clips/hat channel or a double stud wall following a "room within a room" principle.
 

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What is green glue?
"Yer not from around these parts, are ya, pardner?" :)

Here is some more information on Green Glue for you. And a ton of current science on sound isolation here.

I used double drywall and green glue 10 years ago in my first theater (it had just hit the market), and I'm using it again this time around. Good stuff.
 

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I'm new to the forum, but I do have a fairly vast knowledge of construction and I've never heard of "green stuff". Of course, there is always things to learn as I'll never claim to know everything. Who is the manufacturer and what is the brand of the product?

Also, I'm curious on how it was concluded that hat channels are better than resilient channels for acoustics? I never heard of a wide spread issue of resilient channels failing and I don't know why any manufacturer would continue to sell the product as-is if they do. It is way too much liability for them to sell a product that is known to fail (too many lawsuits). Perhaps people are not installing them correctly which has caused this conclusion? If you look at the STC ratings resilient channels outperforms hat channels because they better decouple the drywall from the stud. The STC tests are done in a laboratory and certified. Has anyone done any testing or found any test data to show that hat channels perform better than resilient channels? Are you installing the hat channels using a different approach from the typical recommended install?

I've heard of the double wall approach and I would agree that would give you the great performance if you have space.

One thing to make sure your contractor does is to seal the top of the gypsum board and the bottom of the gypsum board with acoustical sealant (I'm assuming your wall is not required to be fire rated). Holes in the walls are actually contribute more to sound going though the wall than the wall itself. Make sure he fills every crack. You can also box out drywall behind the electrical junciton boxes if you want to be uber careful on sealing holes in the walls. I've never seen test results showing it would improve acoustics but it makes sense because you are sealing the hole around the electrical outlet. If you don't want to go to that expense, then at least make sure there is some insulation behind the junction box.

Also make sure you seal around your doors with gaskets if you want to stop noise. There are STC rated doors on the market but if too expensive you could just get a solid door which has some mass to it.
 

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Steve. Look at my last post. I gave you links to the manufacturer of green glue as well as more reading on some of the current state of the art in sound proofing. Resilient channel was never very effective, evidently, and hat channel with clips performs much better and with less chance of installation error (short circuiting with a screw in the wrong place), among other advantages. I don't doubt your construction knowledge one bit, but the soundproofing "industry", admittedly very niche, has come a long way in the past decade or so.
 

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Steve,

Welcome to the forum.

I was once in your shoes having been involved in many large municipal projects where the bigwig architects spec all sorts of stuff like RC.

After joining this forum I quickly learned that those techniques are actually very poor. You have professional designers on this forum who design theaters all day long. When it comes to noise they are going to be the experts, not an RA.

Green Glue, isolation clips and hat channel are used 9 out of 10 times here.. there are more threads on it than you could ever hope to read. If you are curious about RC, then search the forum for "resilient channel" and you are bound to find some explanation of why it shouldn't be used. Find some acoustical data on an RC assembly then compare it to one of the assemblies used here.

Some methods and techniques are so tried and true around here that you will have to look up the answers and study the data. That's not to say that methods do not change and evolve.

Tin
 

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Discussion Starter #15 (Edited)
The whole thing went great. Got the green glue on rush delivery by the next morning... The guys I was dealing with who were building the wall for me seemed skeptical about the green glue - like it was snake oil..... They kept it to themselves for the most part. The one guy couldn't believe how expensive it was for a case... but hey, the research is there.

They basically built a wall over top of the existing wall.... I didn't demo because the existing wall was plaster... behind it was just a wire mesh and brick. 2x6 top and bottom plates, studs 24" OC, a layer of 5/8" drywall, pink insulation - faced batts stapled into the studs, green glue (2 tubes per sheet), and then another layer of 5/8" drywall.

I did a quick test last night as the neighbor was running her LOUD mouth - ran up to the room and it was so peaceful and QUIET! I'm extremely happy so far. Next is having the room painted on Friday.. then I can move all my things back in Saturday. I never thought I'd get this done this quickly, but the guy gave me what I thought to be a fair price. He was there to just replace the ceiling that was damaged from a leak (I had a new roof installed recently to correct this issue).

Only thing that kind of stinks is that once I get my stereo in there, I still have nothing to gauge how loud I can really have it. I'm not really friendly enough with the neighbor to ask if I can run over there and see how loud my setup is!
 

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Sounds great and thanks for the links. I read the post so quick that I missed that. As I typically say I learn something new everyday. Thanks for the links.
 

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Only thing that kind of stinks is that once I get my stereo in there, I still have nothing to gauge how loud I can really have it. I'm not really friendly enough with the neighbor to ask if I can run over there and see how loud my setup is!
Just turn it up 'til the cops arrive. :cool:

I'm not one for going over the top, but I do like to listen to my music and movies loud. You've spent good money to do what you can, so at this point, just play it at whatever level you feel comfortable and let your neighbor deal with it. If it really bothers them, they'll come over and complain.
 

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Discussion Starter #18
Just turn it up 'til the cops arrive. :cool:

I'm not one for going over the top, but I do like to listen to my music and movies loud. You've spent good money to do what you can, so at this point, just play it at whatever level you feel comfortable and let your neighbor deal with it. If it really bothers them, they'll come over and complain.
I hear ya. It's great, it's like the neighbor doesn't even exist when I'm in that room! haha.... It's nice to have a space of my own back like this now... listening room that I can use again. It's made me very happy. I'm glad I did the research for a while though - before I was just going to slap 2 additional layers of 5/8 drywall over the existing wall! Would have done next to nothing.
 
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