Thanks Stuart,
So here's the plan below - though walls will be straight to save time in construction at the expense of a little space. Budget is an issue as baby on the way, so i've had to simplify. I doubt i'll be recording drums.
Document 2 jpeg.jpg
Walls
Inner leaf : Bolted to the existing concrete floor. 100mm insulation slabs, 1x15mm sound bloc. if budget wasn't tight i'dd add two layers, though i think the mass of the brick outer lead makes up for this.
Loads of acoustic caulk .
Any advise on sealing up existing garage doors appreciated (still want it to look like a garage from outside)
Should I add resilient channels?
Ceiling
Semi-independent , extra support via isolation hangers attached to existing ceiling. Ceiling span tables don't account for this extra support. I want to conserve as much ceiling space as possible. the orientation of the room will not allow for joists in-between existing ceiling joists. - i guess the max span would be around 3.5m likely at 400mm centres - whats the small joist i can get away with for 1 layer of 11mm OSB 2 board and 1x15mm sound bloc?
Will add insulation to existing ceiling.
Could anyone advise me on joist size with this added support?
Floor
Nothing special here just insulation , electric underfloor heating and laminate.
Ventilation
Building regulations guy specified both vocal room (really just for storage) and main room should link to one inline extractor fan, which should be the MANROSE MF100T - lowest setting is just 20db. This will feeding into baffle box before exiting.
For passive ventilation intake will use the below item which promises up to 50db isolation - i assume this is better than just using a baffle box and flexible ducting?
ventilation.jpg
If you guys feels I've missed something please let me know!