Building a 2nd structure inside my garage

[Ironcrow]

Oops sorry, I was agreeing with you. I meant why risk the cinderblock structure cracking my slab. My brother in law keeps insisting it will be fine but I've been leaning towards a framed drywall structure.

The drywall structure will be slightly complicated given that I'm going with a double stud wall construction in order to maximize low frequency isolation:

The pink stuff is cheap R13 insulation. The green stuff is green glue, an acoustic compound, sandwiched in between layers of 5/8 drywall. This is a proven method in studios and home theaters when low, rumbling, bass frequencies need to be isolated. Since I have plenty of space, building these double walls should be worth it. The ceiling is another matter, but I have a plan for that.

Consider Bondedlogic Ultra Touch Denim insulation. It is more dense and better for sound absorption than fiberglass. Stagger the studs too, if you can.

 

[Bob_McPhee]

I wouldn't even try a block wall on what is almost certainly a cheap, thin, floating slab. Even if by miracle the side and back wall footings are overbuilt, the inner and front walls will probably destroy the slab. You can do great things with lighter, easier to handle materials.

yeah, lol.

A qualified expert, tasked with this project, would NOT be building a second block wall and would NOT pour a 2" concrete 'ceiling'.

A qualified expert would simply take the existing room and soundproof it. No muss, no fuss.

But there is something exciting about doing it 'wrong'...document it on youtube...'crazy man crazy'... all that stuff

These are the kind of responses I was looking for. The unknown qualities of my slab seals the deal, I will NOT be going with a CMU.

Sorry for the late responses, we're wrapping up the school year.