John Sayers' Recording Studio Design Forum Archive

Looking for the proper way to enclose this staircase in my live room build, without any 3 leaf problems. It will be a MAM, room inside a room. The outer leaf mass under subfloor is not far from being done. I have two layers of 5/8 drywall with green glue, cleats, and miles of caulk and 3/8 filler rope. I have 3 wall that are concrete, one wall you see that is 12ft leads to the mixing room. I will be installing two sets of sliding doors going into the mixing room.


Thanks for any advice

are you not planning on decoupling the inner room drywall?

why not enclose the entire stair case? use a single layer of plywood inside, then insulation.

the amount of true isolation you're going to achieve in the approach i'm seeing will be limited to the mass you apply, then all structural. if you can add decoupled hat channel etc to the walls and ceiling, then you can improve on that.

Thanks Glenn for the reply.. Yes this will be a room inside a room, completely decoupled. I will be completely closing off the staircase which would make that part of my outer leaf. There will be insulation and then an air gap before starting the inner room. I guess what I'm asking is do I plywood the inside of the stair wall then add strips 14.5" wide of 5/8 drywall between my staircase studs which are 16" centers. It would become an "Inside out wall". My other option may make a 3rd leaf, is to just plywood over the outside of the staircase studs and add drywall on top of that. Thats the easiest but the inner exsisting drywall I outlined in red would then make a 3rd leaf. I just don't know if that's a problem or not. Thanks for taking the time to respond.

i think you'll have some limitations regardless and a "lightweight" third leaf won't be the most significant, hence the suggestion to go with the plywood - it will help maximize the air space between layers.

Glenn thanks for the help. Before I go any further, Am I going about this the wrong way? Obviously if I enclose the outside of the staircase wall with one layer of 3/4 OSB and two layers of 5/8 drywall, that would be the easiest but is it the right way to do this? Is there any treatment to the under the stairs cavity I need to address? I will put insulation between the studs before I put up the 3/4 OSB. My only thought is when the inner room is put up, use 2x6 walls around the staircase to give more room for insulation. It won't be like Rods book but the only way to make it like rods book would be plywood the inside, opposite of what I'm doing and then cut strips of drywall to fit between the studs and caulk, caulk caulk.

The way I'm doing it would make a better seal but dosn;t make it right lol..

im in a spot that I can change things easy if needed. I will wait for some feedback before I continue.. thanks for all the help here.

The door you see in the pics will be moved. FYI

Also when tapping on the one sheet of OSB that is up, sounds like a bass drum.. the under stair cavity could be a problem for me if I don't address this the right way..

the underside of the stairs should get covered with insulation (damping factor) and of course all the walls /framing need it. if you could perhaps set up some wires and drape it in the empty space, you could leverage that empty space to burn off some LF which will inevitably makes it way into there. set up some wires stud to stud and drape R-30 batts over them - enough to almost fill the space.

Thanks Glenn. Im off to get insulation and the wire. I will address the underside of the stair cavity and continue with the OSB when im done filling the void.. Wire and drapes made out of insulation is a great idea. Im on it..