Rehearsal Room Design

[woliver]

Hi-
I have been researching for months on how to build a soundproof rehearsal room, and I think I finally have a plan. Will this work? Are there any low-cost additions to the structure I can make? I will try to descibe it, I have some basic dimensions and drawings but I don't know how to post them, but if anyone wants to tell me how I can post them.

Here is the plan: Very basic, no frills at all.

I am going to do a room-within-a-room. A large room, about 37x21 to start, with a smaller room about 31x15 inside of it. This will give about 3 feet of airspace on each side, and I would build so there's a foot of airspace on top. I will have 2 layers of 1/2 inch sheetrock on the inside wall and 3 layers of 1/2 inch on the outside wall. Everything will be caulked and sealed, of course.
The doors will be solid core doors, offset from each other by about 20 feet. No windows.

I am going to build one layer of roof with 3 layers of 1/2" drywall and the second layer with 2 layers 1/2" drywall, and deck plank.

I am going to build on a slab, so no floating floors for me. I am hoping to have metal bands play in here with minimal sound leakage. How does this look so far? anything I should change before the blueprints are drawn? Everyone who is in construction or an architect keeps telling me to use soundboard, but I keep reading on here that MASS and AIR are key, and that sheetrock is the most cost-effective and densest way to get mass.

A also had another question: Fire code might not let me build with a drywall/open stud/airspace/open stud/drywall configuation, i.e. I may not be able to put sheetrock JUST on the inside of the inner wall and JUST on the outside of the outer wall. I might have to put it on the inside of the inner wall, and on the inside of the outer wall, as well. This would mean that I have to use some other siding outside of the outer wall. Will this ruin everything by acting as a third leaf? Is there a material that won't vibrate yet will protect the building and make it look decent, or (maybe) will the sound be so dampened by the time it gets all the way outside that it won't make a difference?

THANKS!!

[woliver]

I think I found out how to attach files...
It is an attachment to this post, some rough dimensions.

[avare]

I hope you will have insulation in the cavity. The overall concept looks good. I would spend the extra money for extra layers of drywall and reduce the space between the room walls.

Andre

[woliver]

THanks for the reply. Will insulation help a whole lot, or is this just to increase the floor space inside? Because I was hoping/planning on using the airspace as storage space. Bad idea?

[avare]

Will insulation help a whole lot

Yes, up to 10 points STC.

Andre

[woliver]

Hi-
Is there any way to use insulation while still keeping the space available for storage? Would it be terrible to do it like, from the outside in:

OUter siding - Drywall - Insulation in between the studs - some other kind fo siding to keep the insulation in - AIRSPACE (storage) - More siding to keep the inner insulation in - insualtion between the inner studs - drywall?

Or would this be a 4 leaf system? would the STC gained by the insulation be more than the STC lost by a 4 leaf system?

Does anyone know the answers to any of the other questions, about soundboard, etc?

Thanks

[bpape]

I'd agree with Andre. While a larger space between will help, I can't see you losing all that space.

The best isolation will happen if you fully fill the cavity with insulation - not storage.

Bryan

[woliver]

thanks for the info. Is there an 'ideal' gap size for isolation, that I can still fill with insulation (1 inch, 6 inches, a foot, etc)?

Will I be okay with just sheetrock, if it's well caulked, for mass?