Looking for some advice on isolation for new construction

So an architect is in process of finalizing my drawings for a 1st floor 3 Room addition, and I am at the point were I need to make some final decisions. So I turn to the experts for a bit of advice.

Theater room is 27x15x10 (half of the addition)
Floor is concrete slab (all three rooms will be on separate slab than rest of house). There is nothing above the addition other than attic space. This attic space will be separated from the rest of house attic space by concrete block - some minor punch through for electrical, etc. The two rooms adjacent to the theater will be a game room and an office (not true "living" space)

1) Back Wall - Concrete block - 1 inch air gap - standard 2x4 frame
2) Front Wall - Concrete block - 1 inch air gap - standard 2x4 frame
3) Side Wall - Concrete Block - 1 inch air gap - standard 2x4 frame
4) Side wall (separating theater from 2 other rooms) - 2x4 Staggered stud (2x6 sole plate)

I will do double drywall (5/8) with 2 tubes green glue on all walls.

Question) Is double drywall on ceiling necessary? I assume yes.

Walls and ceiling will be drywalled before soffits are constructed. A/C will most likely be housed in soffits, or come in through ceiling. I still need to determine best way to do this, since room will need a return (advice accepted )

Question) Even though staggered stud is decoupled, it is really still connected by sole plate, and also the door jamb. Anything else that needs to be done regarding the staggered stud?

Question) Is it necessary to put anything between framing and floor, or just anchor to bare concrete?


Although I know this question is subjective, is this "good enough?" Or are there additional things that will be NECESSARY to isolation?, i.e. What else is truly ESSENTIAL for isloation?

Basically I don't want to be that guy that everyone says "Can you believe that chump did DD/GG, Air Gap, Staggered Stud, etc, but he didn't bother to do XYZ, which truly negates what he DID do... and it wouldn't have been that difficult to do XYZ!

But then again I dont want increase my costs and effort 20% for something that will only increase isolation performance by 2%.

Thanks for all the help, I'm looking forward to your responses.

Thanks for the great advice and articles. Can you clarify the "Floating Joist" implementation? From what I can tell, these new joists will basically lie on top of the decoupled side walls, which are merely bolted to the floor. Wouldn't this cause a major stability problem, i.e. what actually holds the "new" joists in place?

So basically the floating joists are merely for weight, and stability (they really don't tie into anything structural). I guess from there, you would DD/GG, screwing into joists at will, since they are decoupled!

I guess the downside is a lot of extra wood, and a pain for the insulation guy, since his normal distance between joists is now effectively cut in half.

Just wanted to update: After room dimension analysis, I can't afford to shrink the theater width or the adjacent rooms anymore (I'm already pushing it). As a result, my room is as stands - 3 1" air gap walls, and one 2x6 staggered stud.

Does anyone know the best way to seal the gap under a solid door that is running over carpet? Or is a transition plate with weatherstripping really the only way to go?

Thanks!

Thats what I thought. I guess I'll try to find a fairly good looking transition to use...

Thanks Ted

So given 3 walls decoupled from exterior block, and 1 staggered stud wall (16OC, I am guessing), are the DC-04's necessary?

Also, if decide to decouple the ceiling with hat channel/clips, how is the drywall actually attached to the track? Standard drywall screws?

I guess anything attached to the ceiling needs to be really well thought out (projector mount, soffit, star ceiling, etc) so it can hit the hat track... you now dont have the option to rig up joist-to-joist pieces of wood for mounting....

Again for me, nobody upstairs, and not really bordering any true "living spaces," so I'm trying to use the 80/20 rule

Thanks!

Thanks Dennis. My room dimension analysis was a little bit less involved... The two adjacent rooms are already under 11' wide; I don't want to make them any smaller.

While I've already decided on airgaps and stagered stud for shared wall, and DD/GG for walls and ceiling, my decision now is on RISC/channel or no RISC/channel for for the ceiling. I know the ideal answer is "Do It," but I am wondering if I am just plain foolish if I do not.

As an aside, to me it seems like many of the folks on this forum have basement theaters in multilevel homes, where I would think isolation is much more an issue. Is this accurate?