John Sayers' Recording Studio Design Forum Archive

Hi,

we're well on our way with the basement studio we're building. the inside of the recording room is steel studs, two layers of sheetrock, and the ceiling is two layers hung on RC.

Here is my problem. I know I'm supposed to caulk the joint between teh wall and the suspended ceiling, and on three of the walls that should be fine, but the attention to detail wavered a little on the 4th wall, and the gap between the ceiling and the wall is too large for just a bead of caulk.

how can I solve this problem? can I put something like foam in the gap, and then caulk over that? or some of that spray in foam stuff? I don't want to short out all of this work with this one joint, but I also don't want to have to take down a whole ton of sheetrock and cut new pieces...

please help!! I'm seeking creative solutions.

thanks a ton, again,

David

Davidlavin:

the gap between the ceiling and the wall is too large for just a bead of caulk.

How wide is it? (e.g. 1/4" is ok)
Is it straight or curved?
How long is it?

Can you add another layer of 5/8" gypsum to the wall to make the wall thicker to cover the gap?

If it's 3/4", then can you fill the space with caulk, and then cover the whole thing with wood molding? That will couple the wall/ceiling, but it would be thick. A similar alternative would be to make a kind of 5/8" deep 'soffit' of gypsum around that part of the ceiling, with a little mud on the inside lip, it could look ok, but I don't know how long it would last without cracking.

Can you cut some wood on a bandsaw and stuff that into the gap?

Can you fill the space with polyfilla ? (I like this one)
If the gap is more than 3/4", then perhaps a roll of window screening and polyfilla.

The only other thing I can think of is to
a) scribe a line with a knife into the lower layer of ceiling gypsum at about 1' from the gap
b) unscrew the gypsum to that gap
c) snap it off
d) fill the upper layer gap with acoustic caulk (even if it's an inch wide)
e) put up a new layer
-- this sounds horribly risky to me because:
1) it mght not break straight, so the whole ceiling would have to come down
2) the screws might push through on the good gypsum part, so the whole ceiling would have to come down
Instead of (a), using a saber saw to the right depth might make the line cleaner and straighter and more predictable and safe for the rest of the ceiling, but I've never used a power saw over my head before and I'm not entirely convinced I'd want to.

can I put something like foam in the gap

Expanding foam is usually not recommended, because it conducts sound well.

Depending on how close the RC is to the wall, I would cut back both layers so the gap is 2"-3" wide. Pain in the ass but so what. You need to fix it. That is the price for not paying attention to details. If the gap is parrallel to the RC, and the RC is too close to the wall, you MAY even have to remove this one piece of RC.

Now cut a 6" wide strip of 3/8" or 1/2" ply, long enough to cut enough pieces to fit between joists(shown) OR the RC without touching at the ends, same thing.
See the picture.

Pre screw two screws as shown(only 1 shown) one at each end of these strips, to manipulate the strip up through the gap to and pull it down against the face of the gyp board on the attic side. Leave a 1/2" gap between the ply and the wall. While pulling down on the handling screws, drive screws through the ceiling gyp bd into the ply as if it were RC. Once you have 3 or 4 screws driven, you no longer have to pull down. It works great. Remove these 2 "handling screws". Now cut your new filler gyp board strips, caulk the joint, and fasten these strips in place, leaving a 1/4" gap at wall. Now you can caulk this gap, tape and texture.
fitZ

Depending on the size of the gap (1 inch or less), you can try something like this: