Converting and soundproofing a detached single skin garage?

[Booty67]

I am a bit confused on how I should be going about this. The current size is 5.27m * 2.50m, I want to keep as much of the width as possible.

I am looking into converting it myself, just unsure how to maximum the noise cancellation and not loosing much width.

I will be getting the door taken off, bricked up and a window installed.

FWIW I wouldn't be listening to it loud ever, I just don't want the neighbours (5m+ away) from hearing me watch The Dark Knight trilogy at 3am

Should I use 70mm rockwool with two layers of acoustic plasterboard?
Or
50mm rockwool with 20mm insulated PIR + two layers of acoustic plasterboard

How should my layers be for both of these

100mm Brick
50mm Air Gap
DPM?
70mm rockwool
Vapour Barrier?
Plasterboard
Green Glue
Plasterboard
Skim
Paint

I don't think I'm getting building regs involved too...

 

[Booty67]

Maybe I should look into this superquilt insulation stuff?

 

[Notch7]

Seal up all the holes, everywhere to stop higher frequency sounds escaping

Low frequency is more difficult it relies on mass to prevent passage of vibration + isolation.

20mm PIR is good for thermal efficiency not acoustic

I’d go with 70mm rockwall and 2 sheets acoustic plasterboard

 

[freddiemercurystwin]

Superquilt needs a 25mm air gap either side to perform properly, it provides very little benefit.

 

[Booty67]

I'm not sure if I've done this correctly. I couldn't find a definite figure for the conductivity of my external bricks, but its pretty negligible

 

[Booty67]

Celotex 25mm + Rockwool 50mm

Although if my calculations are correct 50mm rockwool + 40mm celotex gets me down to 0.28 u Value which I believe is the minium I need for building regs

 

[Booty67]

I've forgotten the airgap in these actually

 

[Booty67]

Thanks for the help so far. So my current plan is

100mm Brick
50mm air gap
DPM
75mm rockwool
Vapour barrier
Plasterboard
Green Glue
Plasterboard

Air gap, DPM, and vapour barrier I assume are needed in this case?

Do you think 75mm of rockwool will be enough to be comfy, this is an office/home cinema room? I will be insulating an air con for heating and cooling.

How should I plan on doing the roof and floor? (This is detected pitched roof, think I'd like to add a loft hatch in there as well)

Floor boards
140mm PIR insulation between joists
DPM
Existing concrete floor

 

[Deluks]

What are you attaching the plasterboard to?
Think about a stud wall that doesn't touch the existing wall, and you'll be on the right track. 3*2 CLS rockwool between, you could use a laminated PIR plasterboard over the lot, and attach a layer of soundblock PB onto that.

 

[Booty67]

What are you attaching the plasterboard to?
Think about a stud wall that doesn't touch the existing wall, and you'll be on the right track. 3*2 CLS rockwool between, you could use a laminated PIR plasterboard over the lot, and attach a layer of soundblock PB onto that.

Yes I will be doing stud wall 50mm from the brick, if that air gap is required. Which I think it is with single skin brick.

 

[Booty67]

Honestly I think

100mm Brick
50mm air gap
DPM
50mm rockwool in 50mm studs
Vapour barrier
20mm insulated Plasterboard
Green Glue
Soundblock Plasterboard

Could be the best of both worlds?

 

[Booty67]

Something like this perhaps if this is correct?

 

[Deluks]

The air gap will be a weak spot in the soundproofing.
You could potentially use cavity slab insulation to fill the 50mm air gap. Designed for use in 'full fill' cavities.

 

[noseall]

Honestly I think

100mm Brick
50mm air gap
DPM
50mm rockwool in 50mm studs
Vapour barrier
20mm insulated Plasterboard
Green Glue
Soundblock Plasterboard

Could be the best of both worlds?

Fit or trap the DPM directly against the brick wall. Allow it to lap onto the ceiling and the floor by 300mm or so.

 

[Booty67]

I could be totally wrong, and this garage isn't single skin brick, this is a house I've bought and in the process of moving into, hopefully in 2 weeks. However, I assumed it was single skin without checking, stupid of me but whatever. But based on the images I have, I've worked out the outside of the garage = 2.9m practically dead on. So what does this mean? Can I forgo the air gap and DPM on the walls?