# Newbie: Building Out The Walls



## Guest (Jul 4, 2007)

Folks --

I am a newbie so give me grace as I learn from you. I am building out my 24x13 x 8.2 home theater and will have 16 on center 2x4 construction done in three weeks. The outside walls behind the framing are concrete and I am confused about appropriate steps to make the room sound good. On DIY TV, I watched the HT Construction episodes and they put R13 insulation in all walls then added fiberglass panels (703s?) in every other stud opening. I also read about putting sound board on the walls before 5/8 drywall. Are both of these steps done for the room sound or for keeping sound out of other rooms.

how should I proceed? Where can I learn more about HT wall construction?

Thank you in advance for any direction you can provide....


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## John Simpson (May 10, 2007)

Here's a great link to get you started Steve:

http://www.bobgolds.com/AbsorptionCoefficients.htm

Also, the various plasterboard manufacturers will have specifications for how best to use their sound-treatment products.


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## bpape (Sep 14, 2006)

Save your money. That DIY special is basically worthless - sorry. There are 2 different things at work here:

- Isolation of the room from the outside world
- Taming interior room acoustics

They are 2 very different things. Right now, youi're in a stage where you can impact isolation. Standard wall insulation will be fine. Save the money you'd spend on 703 and get some PAC DC-04 clips, an extra layer of drywall, and a good solid core door. They'll make a LOT more difference.

Bryan


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## Otto (May 18, 2006)

> Are both of these steps done for the room sound or for keeping sound out of other rooms


The steps you mentioned would be done to keep your room isolated, as Bryan has suggested above. The idea is to keep external noises from coming in to your theater (someone walking on the floor above, a Harley outside, whatever), as well as keeping the theater noise (explosions, pod race scenes, whatever) from bothering everyone else in the house. 

Bryan is right about the clips (I think they're also called RSIC clips). They will isolate your drywall insulation from the studs such that sound does not transmit through the medium (or it is at least greatly diminished). They add cost and complexity, of course, but you only have once chance to "do it right." 

I've also suggested Green Glue in your "welcome" thread between your two potential layers of drywall. I have some that I'm going to be using shortly, but I don't have any results yet. It's the best I could do in my situation (i.e., I'm not using RSIC clips), but I don't know how it'll really perform yet...

I also have solid core doors. I'm using R13 in the walls and double R13 in the joists (yeah, probably should have started with something more appropriate for that space in the joists, but it is what it is). Mine is not a theater space, but more of a workout and guitar/drums/studio space. It doesn't have to be perfect, but I do believe that my efforts will greatly reduce the noise annoyance to the rest of the family, and that's my only goal.

I'm also doing a 2x6 staggered wall. I see you said that you are doing a 2x4 wall, but if you can change to a staggered wall, that will also help decouple the front layer of drwall to the backside layer of drywall for sound transmission.

You also said that you have concrete on the other side of the framing, at least in some cases. I believe that's good, as the concrete is very dense and not a good sound carrier. In my case, since my project is so basic and I like the industrial look, I'm just going to leave the concrete walls and floor.

If you are cutting a lot of holes for outlets or light boxes, you might want to make little drywall boxes on the inside of the framing that enclose them. I've read that those cuts in the drywall (or double drywall) can really let some sound through. I'd be curious to really know how much impact it will make, and perhaps Bryan can comment further. I'm almost to the point where that decision needs to be made, and being tired of the project, I'd really rather skip it. However, if it makes any significant difference, I will do it. 

I also watched those DIY channel specials (or one similar; they also did the 703 panels in every other stud thing). It was OK, but somewhat basic in places. Still, I think I watched every episode that showed up on the DVR. 

Once your room is complete, you will probably need to address the other end of acoustics -- making your room "sound good." If you have a lot of bare drywall, things may become very "bright" with sounds just bouncing all around the room. At that time, you'll consider room treatments to tame the noise, but right now you're at the isolation point.

Good luck!


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## fireanimal (Dec 21, 2006)

Also check out the Greenglue website, they have a lot of information available about sound isolation. For wall framing you should consider either 2x4 on 24" Center, or 2x6 staggered stud, with Double 5/8" Drywall. If steel studs are an option, they are slighty better for sound isolation, but a pain to pull wire through.

Use the R13 in all stud cavities, and save the 703 for accoustic treatments.

You can also try a room mode calculator to see if you can adjust the dimensions of your room before you begin construction.

Also if you will be using GreenGlue, 1 tube per sheet will work well if you are on a tight budget, but if you can afford more use 2 per sheet.

Another option for doors, is to use Exterior insulated doors, with good weather stripping.


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## bpape (Sep 14, 2006)

In addition to the RSIC-1 clips, don't forget the DC-04 clips which tie the room walls to the rest of the house structure in an isolated way to keep from transmitting too much structure borne sound.

Bryan


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## John Simpson (May 10, 2007)

Green Glue -- so is this the real deal? They've only recently started advertising heavily here in Australia, and I think a lot of people are taking their claims with a grain of salt. My plumber mate would just say "use silicon instead"... he loves the stuff.

Steve, there's some nice little illustrations for wall construction at the bottom of this site.


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