# Soundproofing thread



## Mudshark (Feb 8, 2009)

I hope to make this a Soundproofing Thread where we can go to reference information. There has been other threads covering the topic of soundproofing in the past and hope to expand on that information with additional information. There are so many options out there from pre-manufactured board like Quiet Rock, to products like Green Glue that is sandwiched between layers of board. Resilient channel has been widely in use for years, while sound clips attached to the framework and hat channel is another option. 

For a starter I suggest looking at www.soundproofing101.com to get an understanding of the dynamics of soundproofing .
Here are a few links taken from the Soudproofing 101 website that are of interest:


Soundproofing 
Soundproofing.com is a relatively new site which gives more advanced soundproofing information written by industry professionals.

The Soundproofing Company
Green Glue is a next generation product used for soundproofing walls that is not very expensive, yet very effective. This company’s website is the main place to read about and research what this very new product is; additionally, they boast other soundproofing tools that are worth taking a look at. 

Sound Isolation Company
A national distributor of soundproofing products and advice; their products are tested, fully evaluated, in stock and ready for immediate pick-up or shipment.


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## Mudshark (Feb 8, 2009)

Putting up board using Green Glue - not the best example (see post # 7), but shows the glue applied to board


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## moore (Dec 2, 2010)

Mudshark said:


> Putting up board and using Green Glue
> 
> http://www.youtube.com/watch?v=rVtY6MZoFrY&feature=related


Two hangers with a lift???:blink:


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## Mudshark (Feb 8, 2009)

moore said:


> Two hangers with a lift???:blink:


Yeah I know, but did you notice one guy was just talking and not working? I suppose it made a good height to apply the glue to the board though.


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## Mudshark (Feb 8, 2009)

:walkman:Soundproofing with clips and hat track :walkman:


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## boco (Oct 29, 2010)

Ok, just went to a job condo job with 28 units with the sound proof crap. Ceilings only. Then double 5/8s Proroc. What a nightmare. Very few butts but the seams are looking ugly. Not much of a bevel. Last time doing them i had some problems with delayed shrinking and or tape swelling. They are small places 4800sq each. So basically i need to turn 2 over per week. Start Mon, prime Fri. Heat is no problem as each unit has 2 240w heaters and fans. My main concern is the ceilings looking good at night. Any tips would be helpfull. I only have 4 days per unit. If i had mopre time it wouldnt be an issue.


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## Ted White (Jul 14, 2009)

I like the thought of the thread. 

I would not use the Green Glue video as a resource for the following reasons:

A soundproof wall would not use ½” drywall. We want the mass of 5/8”

Much better framing than 24” OC is to actually decouple the drywall from the frame.

Cotton insulation does no better in a wall or ceiling than cheap fiberglass.

You would not leave a ¼” gap at the edge of the wall. It absolutely does NOT decouple anything.


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## SlimPickins (Aug 10, 2010)

Ted White said:


> I like the thought of the thread.
> 
> 
> 
> You would not leave a ¼” gap at the edge of the wall. It absolutely does NOT decouple anything.


I didn't watch any videos, so I'm not sure what you're referring to, but I thought the gap around perimeters was indeed a form of decoupling?


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## Ted White (Jul 14, 2009)

Nope. It's one of those things that seems to make sense but does not, in fact. Whoever instructed them in that video has less than accurate informaton


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## Mudshark (Feb 8, 2009)

Good to see you on this thread Ted. Interesting about the gap at the edge of drywall. I used to wonder about that, when some resources would have you caulk the gap and then cover with tape and mud, effectively joining them anyway. Yes I see the point on 1/2 inch versus 5/8 inch, makes perfect sense.


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## Ted White (Jul 14, 2009)

There are an AWFUL lot of urban legends thrown around out there. While the internet is great for getting good info, it's also great at giving you bad info. The 1/4" gap is one of these myths. 

Many of the myths revolve around what is intuitive to the average person. Leaving a gap seems to make sense on the surface. As does using an exotic insulation or extravagant specialty drywall. All of these things make sense at some level, however when we review hard lab data, we see a different picture.


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## SlimPickins (Aug 10, 2010)

Ted White said:


> There are an AWFUL lot of urban legends thrown around out there. While the internet is great for getting good info, it's also great at giving you bad info. The 1/4" gap is one of these myths.
> 
> Many of the myths revolve around what is intuitive to the average person. Leaving a gap seems to make sense on the surface. As does using an exotic insulation or extravagant specialty drywall. All of these things make sense at some level, however when we review hard lab data, we see a different picture.


I worked on a large apartment complex a few years back where all the lids were RC with double layer. Gap at the wall, and then gap at the lid when walls went up. That's an awful lot of labor thrown at an urban legend.

I suppose gaps don't make any difference when sound is being transmitted through the framing members....it would make more sense to soundproof the subfloor between units...a "whole-istic" approach, with forethought thrown in for good measure.


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## Ted White (Jul 14, 2009)

The thought that lots of labor = no urban legend isn't always a good litmus test. For example maybe once a month we see architectural diagrams _in new construction _showing resilient channel being applied to the first layer of drywall even though there is definitive lab data clearly showing how ineffective that is. So not at all uncommon to propose a more labor intensive technique that has little to no value. 

At issue is the edge constraint of the ceiling and how much that might limit up and down oscillation of the drywall. The reason to introduce clips and channels (or resilient channel, though we never ever recommend that product) is to give the ceiling the ability to bounce like a spring. The legend being that leaving the gap at the perimeter will allow maximum bounce.

Of course that's technically true, however we backfill that gap with sealant and hope that the sealant holds, and never separates from the drywall, exposing a clear crack. When we fill the caulk into place, that in and of itself will limit the movement of the wall or ceiling panel. So what have we really gained in a practical performance standpoint?

If the ceiling were a closet ceiling this technique would make more sense. A 3' x 3' ceiling would in fact have hindered movement because of edge constraint since the ceiling is so tiny. Look at a normal room ceiling and the edge constraint becomes a moot point. The ceiling will bounce up and down (1/16" max) just fine unless the ceiling is in a closet.

_Technically_ having zero edge constraint would be a good thing, but from a _practical_ standpoint this is not a factor. You just won't hear the difference. What is preferred is to run the wall drywall to the ceiling tight. No gap = no seal failure and it's certainly easier NOT to purposefully leave the gap, as you said, Slim.


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## Ted White (Jul 14, 2009)

SlimPickins said:


> I suppose gaps don't make any difference when sound is being transmitted through the framing members....it would make more sense to soundproof the subfloor between units...a "whole-istic" approach, with forethought thrown in for good measure.


I think this is accurate


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## SlimPickins (Aug 10, 2010)

Ted White said:


> The thought that lots of labor = no urban legend isn't always a good litmus test.


That's where I was going with my statement....I think we've all seen poor design running under the guise of "good planning". I remember at the time thinking that the gaps were a waste of time, when they'd simply get filled with mud, creating a point of contact. I've never liked the idea of two layers of 5/8 being held up with RC.


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## Ted White (Jul 14, 2009)

We're on the same page


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## Mudshark (Feb 8, 2009)

*To insulate or not to insulate*

Ted - To insulate or not to insulate - should ceilings between floors be treated with insulation or is it better to have that air pocket?


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## Ted White (Jul 14, 2009)

Well, that's a good question. Insulating the cavities improves performance. Here are the guidelines:

Look to fill the cavity 75% full of insulation. 100% is really no better, but if the cost difference between 75% and 100% full is meaningless, then go ahead and fill the cavity.

Cheap Fiberglass works as well or better than anything, so don't look to spend silly money on insulation. If mineral wool is cheaper, or you like the harmless fibers of cot tom, then by all means go ahead. Just understand that these products, while often costing a great deal more, will not perform better.

I like paper faced insulation if using wood framing so I can staple in place.

It doesn't matter if the insulation is up high in the cavity, down low or in the middle. 

Never compress the insulation when installing. Another urban legend. Compressed insulation can conduct a vibration.

Blown in cellulose or fiberglass can compress at pinch points when used after the drywall is up. Blowing insulation is a risk.

Insulation works best with decoupled framing. Less effective in a coupled wall. 

Insulation in a coupled wall might get you a couple points increase vs. un-insulated coupled wall.

Insulation in a decoupled wall might get you 5 points vs. an un-insulated decoupled wall.


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## Mudshark (Feb 8, 2009)

Speaking of urban legends....


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## Ted White (Jul 14, 2009)

I would not have built the wall they built...


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## Mudshark (Feb 8, 2009)

Ted White said:


> I would not have built the wall they built...


 
I would not have done many of the things Holmes does - but he markets himself well. :yawn:


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## Ted White (Jul 14, 2009)

...


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## Mudshark (Feb 8, 2009)

*Soundproofing Walls and Sound Transmission Class (STC)*

Soundproofing Walls and Sound Transmission Class (STC) is discussed in this link: 
http://www.soundproofingcompany.com/sp-solutions/soundproofing-walls/


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## Ted White (Jul 14, 2009)

You can build a very well isolated room at a reasonable cost if you follow the following basic, tried and true methodology.

#1 Decouple the framing. This can be done with staggered stud or double stud walls. To decouple the ceiling, consider clips&channel. Resilient Channel (RC-1) attempts to decouple, however there is no industry standard or specification for its construction, so there is concern about using it.

#2 Install absorption in the cavities. This means standard fiberglass R13 in the walls, R19 in the ceiling. Know that there is no data that supports that any other insulation (including the “acoustic” labeled, and recycled cotton) works any better. Also, foam (open or closed cell) is superior for thermal, but distinctly worse for acoustic. Use the cheapest fiberglass you can find.

#3 Add mass. Nothing better than standard 5/8” TypeX. Great mass at 70+ pounds a board, and cheap at $7 a sheet. Use two layers. Only mud and tape the final layer.

#4 Consider damping these drywall panels with one of several field-applied damping compounds. Some work better than others, and independent lab data shows you get what you pay for here. 

After that, you’d turn your attention to the ventilation, lights and doors. All of these are flanking paths for sound to get out of the formidable room you just built. They can be dealt with fairly easily, but you’ll want to design this in.


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## chris (Apr 13, 2011)

Ted White said:


> You can build a very well isolated room at a reasonable cost if you follow the following basic, tried and true methodology.
> 
> #1 Decouple the framing. This can be done with staggered stud or double stud walls. To decouple the ceiling, consider clips&channel. Resilient Channel (RC-1) attempts to decouple, however there is no industry standard or specification for its construction, so there is concern about using it.
> 
> ...


 drywall is cheaper and lighter in your parts


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## SlimPickins (Aug 10, 2010)

chris said:


> drywall is cheaper and lighter in your parts


I think he was talking about 8 ft'ers


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## Ted White (Jul 14, 2009)

I was indeed.


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## Mudshark (Feb 8, 2009)

another link showing STC values for wall assemblies from PAC International - makers of Resilient Sound Isolation Clips (RSIC) 

http://www.pac-intl.com/tests_wl_wood.html


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## Mudshark (Feb 8, 2009)

*Green Glue*

Not meaning to push one product over another but this website has some good information. Check out the testing they did to compare Green Glue against other types of applications. 

http://www.greengluecompany.com/


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## Mudshark (Feb 8, 2009)

*Donnaconna board*

:huh:Shell Busey says....

http://www.housesmartcentre.com/view_article.php?article_id=1006810940049234200 

I notice he uses Donnaconna board - seems a low tech solution but he is putting hat channel overtop of it, then the board. Is there a better way to use the Donnaconna board??


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## Ted White (Jul 14, 2009)

That last link has terrible advice. I would not follow even one of the steps.


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## Trim-Tex (May 4, 2011)

Ted White said:


> You can build a very well isolated room at a reasonable cost if you follow the following basic, tried and true methodology.
> 
> #1 Decouple the framing. This can be done with staggered stud or double stud walls. To decouple the ceiling, consider clips&channel. Resilient Channel (RC-1) attempts to decouple, however there is no industry standard or specification for its construction, so there is concern about using it.
> 
> ...


Great advice Ted! Attention to detail is important! Here are a few ways to improve the .005" thick paper connection at head of wall.









Super Seal Tear Away # 9210 permanent gasket seal that reduces sound.









Flat Tear Away # 9000








or add a quick layer and hide the acoustical caulk


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## chris (Apr 13, 2011)

Pretty slick:thumbsup:


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## Ted White (Jul 14, 2009)

Slick, but purposeful gaps are not recommended. http://www.soundproofingcompany.com...oofing-tip-ceiling-to-wall-seam-intersection/


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## Trim-Tex (May 4, 2011)

Aesthetics are the big part of a finishers work day, and their finished projects are usually judged on having straight, sharp, clean lines on inside/outside angles, good looking corners, plus flat walls and ceilings.
Angle taping over sealant that is not perfectly flat, out of square rooms, shrinking lumber, truss uplift, unrealistic deadlines and less than perfect drywall are what they have to deal with everyday. Your drawing looks good in a perfect world but they don't work in one! 

I'm just trying to help them by giving ideas on nice aesthetics, clean lines, while offering protection from deflection, uplift and all the issues other issues listed above. 

How about we work together and provide options for the drywall professionals that help them......sound control, aesthetics and call back protection, ect.?

Peace, Joe


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## Ted White (Jul 14, 2009)

It's very simple to have a thin application of sealant applied. No bulge, no problem. Cheaper, more effective, faster. I like that combo.


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## chris (Apr 13, 2011)

probably wrong thread to post but to make point on aesthetics.you can either flat tape and caulk,caulk only or put up tearaway:yes: (zipstrip) not only looks better but definetly does a better job and lasts forever:thumbsup:


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## Ted White (Jul 14, 2009)

Nice. For acoustic considerations, caulk first. We want the flexible sealant up into any gaps. Despite the goal of drywall to drywall contact, there may still be gaps. A taping blade can also square up that joint, particularly if you're using a latex-based sealant. 

It's done all the time with great success.


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## Mudshark (Feb 8, 2009)

Some further views on soundproofing from the Super Soundproofing Co. in California.
http://soundproofing.org/infopages/channel.htm


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## Ted White (Jul 14, 2009)

Keep in mind, some dealers sell everything that can possibly be thrown in. Not based on lab data, but rather based on what they can extract from a customer.


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## Mudshark (Feb 8, 2009)

Ted White said:


> Keep in mind, some dealers sell everything that can possibly be thrown in. Not based on lab data, but rather based on what they can extract from a customer.


So true Ted. Its not whats in it for the customer, but its whats in it for them with some of the sellers out there. Hopefully anyone looking at any of these links can educate themselves accordingly.


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## Ted White (Jul 14, 2009)

What really, really bugs me is that most dealers sell based on what they believe the customer will swallow. This is why Mass Loaded Vinyl (MLV) sells. It's very profitable for a dealer and intuitive to a customer that heavy rubber should be a good thing in my wall. So it's pushed with lab-proven limited results

Same with cotton insulation. Intuitive to a consumer that insulation plays a big role in soundproofing, which it certainly does not.

Rubber strips under the bottom plate of a wall is another useless waste of funds.

Foam strips on the edge of a stud or joist. Same thing.

OK I'm done with my rant


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## Mudshark (Feb 8, 2009)

Thats OK Ted, thats the stuff we need to hear - what NOT to do. :thumbup:


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## Ted White (Jul 14, 2009)

I'm afraid I sound like a whiner, but it's shocking and embarrassing to hear what some people are told they need by the time they call. Gives the whole soundproofing industry a black eye.


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