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A thread about wall construction

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Curious here, I know I'm opening a can of worms but, if I'm building a room inside a room, how much does is matter where I put the mass?

What are the merits of symmetrical construction as opposed to asymmetrical? For instance... Two layers of drywall, wood frame, insulation, air, wood frame, two layers of drywall - vs. - One layer of drywall, wood frame, insulation, air, wood frame, and three layers of drywall.

As long as it's all sealed up, how significant is the difference? I'm building inside an existing structure and I intend to remove the layer of drywall on the inside of the space and build inside it. Yes, I can add an extra layer to the outside of the existing wall but that would involve removing/replacing a few existing parallel walls, adding the second(or third) layer and then replacing the parallel walls.

Can I use the drywall that I remove from the inside leaf to reinforce the outside layer by green gluing it to the inside of the outside wall if I place it between the studs?

Now that I think about it, I'm willing to bet that the existing structure is built of 1/2in. sheets and I will be using 5/8in.


I would skip the Green Glue / Resilient channels etc, focus on a well thought-out wall assembly and add mass instead.

Here's a couple documents that will for sure help you too:



Awesome! I'll be back in a week with more questions.

I'm with Thomas on this one.. Build a simple, but massive wall... Watch your flanking paths and keep it simple.. 2x 5/8" - Stud(Insul) 2x 5/8"... Build it tight and seal it up. On Inner walls, we try to use a min of three layers (materials may vary) just to have a rigid leaf on the inside (of floating rooms). Rarely do we go over 4 layers (diminishing returns) because of mass law.


Ok, I've read and digested all of this but the math involved in the flanking study is waay over my head. I think I have a good idea of what needs to be done here but as always, there are lots of variables.

In the interest of full disclosure, there is an existing thread here...



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