I know there are no stupid questions really....but.......

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rushfan33

rushfan33

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.....there are stupid people, and I feel like one of those at the moment! :o

A home studio is finally a real concept. We now own the house and the garage is mine! I've been reading TONS of threads about the subject of construction and have done search after search. Here's what I can't visualize:

1. I read that Durarock is great to use to increase mass. I read that it should be applied between the studs as opposed to on top of the studs. Any truth to that? It just so happens that the contractor that rebuild our kitchen & bathroom ordered about 10 sheets too many of 3x5 Durarock.

2. Is firecode sheetrock mainly for safety or does it actually offer additional sound "control"?

3. If I were to build a floating floor for the drum/live room, would that mean that I'm building a floating room essentially? The studs would sit on the floating floor as usual.... right?

4. Ceiling connection- I read that you shouldn't connect the sheetrock on the walls directly to your ceiling sheetrock (I may have misunderstood), but I can't fathom how to seal the connection.

5. I read that if building a room within a room, the second(new) wall should rest on the neoprene pads. The problem is that if a pad is 1" thick, that would leave a 1" gap on the bottom of that wall to the concrete. It simply said to just caulk. That just doesn't sit right with me! Any thoughts on that one?

Lastly, should I caulk sheetrock joints before I mud and tape them?

Thanks,
RF
 
rushfan33 said:
.....there are stupid people, and I feel like one of those at the moment! :o

A home studio is finally a real concept. We now own the house and the garage is mine! I've been reading TONS of threads about the subject of construction and have done search after search. Here's what I can't visualize:

1. I read that Durarock is great to use to increase mass. I read that it should be applied between the studs as opposed to on top of the studs. Any truth to that? It just so happens that the contractor that rebuild our kitchen & bathroom ordered about 10 sheets too many of 3x5 Durarock.

2. Is firecode sheetrock mainly for safety or does it actually offer additional sound "control"?

3. If I were to build a floating floor for the drum/live room, would that mean that I'm building a floating room essentially? The studs would sit on the floating floor as usual.... right?

4. Ceiling connection- I read that you shouldn't connect the sheetrock on the walls directly to your ceiling sheetrock (I may have misunderstood), but I can't fathom how to seal the connection.

5. I read that if building a room within a room, the second(new) wall should rest on the neoprene pads. The problem is that if a pad is 1" thick, that would leave a 1" gap on the bottom of that wall to the concrete. It simply said to just caulk. That just doesn't sit right with me! Any thoughts on that one?

Lastly, should I caulk sheetrock joints before I mud and tape them?

Thanks,
RF
Click to expand...
No, do not caulk the joints in sheetrock before taping. It will cause cracking in the tape joints as the caulk cures.

I think a good butyl caulk would work fine for those floating gaps, just try to keep it thin to prevent sound transmission.
 
I've always heard that you should use two layers of sheetrock and stagger the joints.
 
#1 - I dunno?

#2 - Fire code sheetrock is thicker, usually 5/8", and it provides a certian "fire rating" or time that it would take to burn through; usually one hour. The very nature of it being thicker and more dense would add to sound control.

#3 - Right.

#4 - I'm not sure. I believe the idea is to decouple the walls and ceiling from room to room, not necessarily decouple them in the same room.

#5 - If you're going to use a 1" thick neoprene pad, you'd need to anchor the sole plate to the foundation or subfloor by using those concrete anchors and lag bolts. Those will allow you to really torque the sole plate down and squeeze down the neoprene pad. Additionally, when you load the wall with sheetrock, which is really heavy, that gap will be minimized. 1" neoprene seems extreme to me, but, what the hell do I know!?
 
For sound proofing, the name of the game is MASS, as long as there are ZERO holes or cracks. So, installing Durock is OK in place of sheet rock, as long as you fasten it without breaking out around the holes, and caulk the fasteners. There are only TWO places the mass should go - either part of the INNER leaf of the wall, or part of the OUTER leaf. In other words, there should be ONLY TWO centers of mass and only ONE air space in a sound proof wall. Ignoring this particular design feature can cost you as much as 22 dB of Transmission Loss, using the EXACT same amount of materials!

If you're sound proofing an existing room and have access to the OUTER wall panel but only from the INSIDE, then you can cut sheets of Durock or sheet rock to fit between the studs and up against the outer wall leaf, in order to beef up the outer leaf's mass. Otherwise, it's better to have un-broken sheets OVER the studs if possible.

I believe I read that Firecode sheet rock is maybe 1 dB better than 5/8 standard sheet rock, but I'm not positive on that. If I did, it was either here

http://www.usg.com/Design_Solutions/2_3_8_tableofcontent.asp

or here

http://www.usgaction.com/handbook/toc.htm

3. - Yup.

4. - Depends on what's already there, and whether you're building a true room-in-a-room. If you're putting walls up to an existing ceiling without changing the ceiling at all, you should build them to within 1/8"-1/4" of the ceiling, then caulk BOTH SIDES with true acoustic-rated caulk. The acoustic stuff is normally heavier bodied and gives better sound blocking, as well as not hardening so cracks don't develop. A 1/64" crack 4-5 feet long will drop the STC of a good wall anywhere from 6-15 dB.

If you're building a full room-in-room, and have the necessary height, it's better to suspend the ceiling INSIDE the walls using commercial dampeners on EACH WIRE for isolation from the outer structure. This ceiling should also have two leaves separated by insulation, and caulked at the junctions of both the inner and outer leaf, where they meet the wall.

Remember, any building material that extends beyond the sound proof (hopefully) room can carry structure-born sound. Leaving the gap between walls and ceiling and using acoustic caulk dampens this transmission (good thing) Better is not having construction materials common to two areas that need isolation - this is harder to do.

5. - The only place you would use neoprene that thick would be UNDER a floated floor. If you have to resort to bolts thru the neoprene, then don't bother with the neoprene because you just "shorted it out" -

There are two ways of building an isolated room - one is to float the floor (physics of this are more complex than most people realize) and rest the walls on TOP of the floor, then rest the ceiling on top of those walls. 1/4" neoprene with caulking inside and out is used under the wall frame and between the wall and ceiling frame. You want no rigid coupling between any inner surface if possible. You CAN rest just the ceiling joists on neoprene, then build the ceiling INSIDE the walls after the walls are done, suspending the ceiling's inner leaf inside the walls, making sure to leave a small gap for caulk.

The second way is to float the walls separately from the floor, resting them on the original floor with 1/4" neoprene, and building the ceiling as in the above paragraph. When you do this, you need to put a "surround" board of Celotex or other soft material around the perimeter, so the floated floor doesn't have hard contact with the walls. Caulk this joint well.

It doesn't hurt to caulk sheet rock joints for INNER layers, but tight construction and offset joints are more important.

Before you go to all this work, remember the "weakest link" scenario - 60 dB walls are a waste of time if you cut holes in them for electrical, leave cracks anywhere, use cheesy doors/seals, etc - I read one experiment where they built 60 dB walls, put two solid core doors (not sound lock, just one in each side of the wall) then CAULKED THE DOORS SHUT, and it STILL lowered the STC to something like 45... Steve
 
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