Here is the situation:
The room was built by the builder during construction of the house. This wasn't an addition or anything. In fact I chose this house because of this room was included in the floor plan.

The drywall was "finished" by the builder approximately 5 years ago. By "finished", I mean it was completed with tape, mud, texture and paint just like normal walls in a room in a completed house. So in theory the room is sealed.

The 2nd layer was just finished (by yours truely :o) using 5/8" DW, with GG in between. Each sheet was hung using 2" DW screws (into studs when possible).

My plan is to cover the walls with acoustical treatments (Linacoustic or some substitute) and acoustical fabric. So I won't be painting the walls and you shouldn't be able to see the DW.

Here is the confusion:
I read in another thread that if you are going to mud & tape the 2nd layer of DW, then you don't need to bother doing so for the 1st layer. I believe I even read some say you can get away with just using some acoustical caulk on the 2nd layer if your going to be covering it with acoustical fabric and treatments. I am sure some purists would say "you must suffer the pain to see the gain" and deem it necessary to mud & tape both layers. Either as a cruel joke or just to see me start crying again. :(

Here is the question:
Now that I am finished hanging the 2nd layer of DW, do I have to go back and mud & tape it, caulk it, or (my personal favorite :D) move on to the acoustical treatment (aka, do nothing else to seal the DW)?

I actually kind of figured that I would need to caulk it originally, but then I wasn't sure since my first layer was "finished". Now after completing the hanging of the DW, I am even less sure that the caulk will be necessary.

Any help / thoughts are appreciated as always.

Caulk it quickly. Take care around outlets, etc. Also where the drywall contacts the floor

If you are going to cover it with fabric, why not just do a rough job of mudding and taping it, and don't even bother with sanding?

CJ

If you are going to cover it with fabric, why not just do a rough job of mudding and taping it, and don't even bother with sanding?

CJ

That was going to be my suggestion. I’d probably just put the first layer with tape up on the seams and not even bother with spotting the screw heads. At least that way the panels are taped together and off you go without bothering to sand.

Plus I would assume that a bucket of mud and a roll or two of tape would be cheaper than caulk, but I don’t know how much caulk a person would need.

-Suntan

Just keep the joints of the first layer tight. If you have existing wall, you're set already, obviously.

Apply second layer. Again keep the joints of the second layer tight.

You can seal everything with crude mud & tape layer, no problem. Or seal it up with sealant.

Possible advantage to mud & tape is that when the theater room goes away after you sell the place, you can maybe finish the drywall quicker. Also, a mudded wall is theoretically heavier...that's always good for sound.

Also, a mudded wall is theoretically heavier...that's always good for sound.

You definitely don't want to use lightweight joint compound then :)

I would caulk and then put a single coat of primer over the drywall. Tape and mud is not necessary.

hate to hijack this thread, but when doind dd and gg, i know the first layer of drywall gets screwed to the studs, but what about the second layer? does it also get screwed to the same studs or just to the drywall? thanks.

Screw to studs.

Okay, after much deliberation and contemplation... ok, not that much really...
I think I am going with the caulking. I was about to go with the crude mud and tape technique, but found some "50 year" caulk at Lowes and the convenience of the caulk (not to mention Dennis' blessing) made me go with that. But before I get started, I just wanted to make sure I had the right stuff. I bought this "DAP Premium Elastomeric Latex Sealant" at Lowes based on other threads where I have read that the acoustical properties of "50 year" caulk and acoustical caulk are equivalent.

Will this caulk work?

http://akersfamilyonline.com/albums/theater/drywall/Drywall_062009_260%20(Medium).jpg

Will this caulk work?


Yup, it'll do just fine!

Make sure you prime the drywall -- sheetrock is not made to stay "open" to the environment after installation - it needs to be sealed with a decent primer.

Any of the common primers (HD/Lowes/SW/Ben Moore/Porter, etc.) will do just fine.

Do you mean prime the second layer, the first or both?

I would have thought with green glue going in between I wouldn't have to do anything to the 1st layer but maybe caulk.

I would have thought with green glue going in between I wouldn't have to do anything to the 1st layer but maybe caulk.


That's true.