John Sayers' Recording Studio Design Forum Archive

First, you should check out this thread

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=1114

and see if it applies to you - if so, this is going to get expensive and time consuming or it will fail, near as I can tell.

Stuff on concrete walls - depends on the dryness of your space, how it's drained/sealed already (see next links)

http://irc.nrc-cnrc.gc.ca/fulltext/prac ... c47024.pdf

http://www.buildingscience.com/resource ... ystems.pdf

Any wall that will NOT have Resilient Channel toward the sound room needs to be isolated from structure, especially at the top of a basement wall - otherwise, you'll get a lot of flanking into the rest of the house. See this link for more -

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=2553

Outer walls arent critical if they are on separate frames - it's the inner wall surface that needs to be either RC'd or the frame floated.

If you're short on space you can install the lath (screws) BEFORE you tip up the wall frame - another way might be to use a right angle drill such as the Makita, with a short screwdriver bit - this would still need at least 5" or so between the concrete and the face of the stud where the lath will be attached.

Typical is that you build the frame on the floor in front of where the wall will go - then lay a bead of caulk across the floor where the frame will set, and tip up the frame. you only need to leave about 1/4" off total height between floor and ceiling joists for the frame to be able to tip up. Then, you can either get crazy with sway brackets or add shims and nail the frame to the ceiling joists - if you fasten the frame hard like that, you'll need to use RC for the wallboard on that wall.

Ceilings should be suspended on RC INSIDE the walls if you want best isolation - otherwise, the ceiling wallboard will flank noise into adjacent areas... Steve

Thanks, Steve. I'm reading through those links now. But, let me show you a couple of drawings regarding attaching the outer wall leaf to the ceiling joists and whether using blocking is required. The first pic are the walls running parallel to the joists and the second is the outer wall running perpindicular to the joists.

Sorry, got as far as your post and need to leave for night shifts; I'll do more tomorrow eve - first, I'd swap your inner and outer wall construction, and swap the soundboard for another layer of (half-price, better mass) gypsum. This will give a couple dB better TL, but will also slightly improve bass absorption inside the room.

I'll have to look at your other questions more tomorrow... Steve

Steve, I think I found the answer (yours) on another thread and I think I finally understand how to do this. I'm gonna post a drawing in a few minutes so that we can clearly communicate on this thing.

Is this right?

Oops, there is a mistake in the above pic. It shouldn't sat "2x4 blocking", it should just say "blocking". I know 2x4's won't fill the gap in 8" wide joists. Anyway, I hope you get the point. This next pic is the same thing but looking the direction of the joists. So, do you fill the blocking with gyp and insu?

Looks like you've got it down pretty good - but since wood framing is only about 85% as dense as gypsum, it's better if you extend the double gypsum as I've changed your drawing - this way, your outer leaf is continuous and part of structure, so doesn't need to be resilient; the inner leaf is decoupled from structure and is continuous also.

As I mentioned, I would forget the sound board/celotex stuff and replace it with a layer of 1/2" gypsum between the two layers of 5/8 rock on the one side; then two layers of 5/8 on the other side, and you're set... Steve

Thanks, Steve. That's great help!!

One thing I didn't catch - since your ceiling will be only two layers of drywall, you would likely see better isolation by keeping each leaf at a consistent strength; this would mean moving that extra layer of 1/2 wallboard to the OUTER leaf, where your added ceiling mass would match it closer; that way, you'll have a heavier leaf for the outer, and a lighter one for the inner - this should also make for less bass trapping needed to balance things out, since the lighter inner wall should flex a bit more and act (a little bit) as a panel bass trap... Steve