Frame on slanted concrete slab

[mcdermott]

Guys,

Newbie here, I've never done any real framing, nor have I had any real construction experience, I'm good with my hands though. I'm about to build a tiny room in my garage so I can play drums, and obviously so my neighbors won't hear it. A simple question:

What is the best way for me put down a level frame in my concrete slab in the garage is slanted? Can someone explain this probably simple task to me?

Thanks

[tooltroll]

Are you framing all 6 sides? To be soundproof, complete enclosure (to the point of air-tightness) and isolation (from any other structures) are required. Professional studios go to extremes when building, even as far as mufflers on all air ducts and separate concrete slabs on springs . Obviously, for a little practise room like you're suggesting, building it like a high end studio is overkill, but knowing the theory helps.

If I was building it, I'd basically build a shed in the garage, 2x4 & OSB (2 layers of 7/16", joints staggered) floor, blocked and shimmed level; 2x4 walls and ceiling, stuffed with fibreglas batts and drywalled both sides; and an exterior insulated door with weatherstripping. Vent it with good lengths of fiber ducting in and out (the longer the ducts are, the more the fiber can absorb the sound) with perhaps a decent kitchen or bath exhaust fan to move the air.

[mcdermott]

Are you framing all 6 sides? To be soundproof, complete enclosure (to the point of air-tightness) and isolation (from any other structures) are required. Professional studios go to extremes when building, even as far as mufflers on all air ducts and separate concrete slabs on springs . Obviously, for a little practise room like you're suggesting, building it like a high end studio is overkill, but knowing the theory helps.

If I was building it, I'd basically build a shed in the garage, 2x4 & OSB (2 layers of 7/16", joints staggered) floor, blocked and shimmed level; 2x4 walls and ceiling, stuffed with fibreglas batts and drywalled both sides; and an exterior insulated door with weatherstripping. Vent it with good lengths of fiber ducting in and out (the longer the ducts are, the more the fiber can absorb the sound) with perhaps a decent kitchen or bath exhaust fan to move the air.

Thank you very much Bob for the reply. You changed my thought process, I was initially thinking of cutting the vertical 2x4's at an angle (long-ways) to compensate for the slant on the concrete slab. From there I would frame up walls etc. And, yes once I stepped in through the door, my drum set would sit on top of the concrete itself. I have read though in other forums that a floating floor is really the way to go.

One more question - I'm also going to build a room within a room using your basic instructions. Any advice or "told ya's" for that? The only thing I've really thought of thus far is to build the bigger outside room first. I'm going to drywall both sides of the outerwall, at least 2 or 3 panels thick, and of course insulation inside of that. The "inside" room will also have drywall on each side.

[tooltroll]

Wow! Double walls with 2-3 layers of drywall? You must have really cranky neighbors! Your thinking is sound though, (no pun intended,) the more mass to the floor/walls/ceiling, the less noise it transmits. Are you planning on doubling the floor and ceiling? Honestly, unless you do, there's no point in doubling the walls. The whole thing is as good as the 'weakest link'.

An alternative would be to use a 'staggered stud' framing; I've attached a sketch showing a typical arrangement. The idea is to decouple the inner wall from the outer, so sound won't transmit through the studs/joists. Filled with fibreglas and an inch of drywall on each side, you could set a hydrogen bomb off in it, and your neighbors wouldn't complain (because they'd be incinerated in the blast, but that's beside the point.) Note that you'd have to frame the door with 2x6s, and I'd recommend double doors; one opening out, and the other in, both solid/insulated and weatherstripped for a good seal.

If you do go with doubling everything, I'd do it in this order:
Outer floor
Inner floor
Frame inner walls & ceiling
Insulate & drywall inner room, both sides
Frame outer walls & drywall inside while they're lying flat
Tip outer walls up, insulate & drywall outside
Now the tricky part:
Frame the outer ceiling and slide it partway onto the room (You'll need to have a temporary 'wall' to sit the free end of the frame on while you drywall the underside; A 2x4 frame with some diagonal bracing should work for this.)
Drywall the underside part you can get at
Slide the ceiling over so you can drywall the rest of the underside
Once you've got the bottom drywalled, slide it into place
Insulate and drywall the top