Plasterboard Corner Layout (gap?)

[famadorian]

I found this picture and I wonder if it's correct?

When using several layers of plasterboard, do we leave such a gap in the corner for caulk?

[Soundman2020]

Hi. Please read the forum rules for posting (click here). You seem to be missing a couple of things!

When using several layers of plasterboard, do we leave such a gap in the corner for caulk?

That's one way of doing it, yes. Another is to use backer rod if the gap is large or deep. A third way is to just caulk each joint once the drywall is in place.

- Stuart -

[famadorian]

Hi. Please read the forum rules for posting (click here). You seem to be missing a couple of things!

When using several layers of plasterboard, do we leave such a gap in the corner for caulk?

That's one way of doing it, yes. Another is to use backer rod if the gap is large or deep. A third way is to just caulk each joint once the drywall is in place.

- Stuart -

Right, but which way is correct or which way yields most soundproofing? If you just caulk each joint, is that as effective as having a gap?

[Soundman2020]

Right, but which way is correct or which way yields most soundproofing? If you just caulk each joint, is that as effective as having a gap?

Both methods work. The difference is in decoupling: if you want to decouple the drywall on one wall from the drywall on the adjacent wall, then leaving a gap and filling it with caulk will help to do that, but it isn't strictly necessary. You'd only need to do that it you were looking for very high isolation, and had taken all the other necessary steps to get very high isolation. So for most home studio builders, decoupling like that isn't necessary , but you can if you feel like doing it.

The two most important points are keeping the surface density consistent, and getting an airtight seal. That happens with both methods.

Caulk has roughly double the density of drywall, so a bead that is at least half the thickness of the drywall s going to give you enough mass to keep the surfaced density. And as long as you apply it properly, it will seal very well in both cases.

- Stuart -