Garage Conversion - Material Suggestions

[Tenatious]

Hello all,

I am going to embark on sectioning off half of a detached garage and turn it in to a music room/gym area so wanted to get some advice on best materials to use and techniques that might come in handy.

At the moment my plan looks something like this:

- Stud wall splitting the garage in half with a door. Insulated plasterboard both sides with insulation on the inside (Need advice on the best insulation to use for the best sound proofing. Seen either Kingspan or Rockwool get mentioned. I did notice places like B&Q have their own cheaper versions. Are these as good?)

- Stud walls on the three single brick garage walls. I was going to line the back of the stud wall closest to the brick with a DPM (Suggestions on which to go for please). Then again, insulated plasterboard and as above an insulation in between the studs. I’ve seen a technique shown on a lot of videos where after doing the insulation between the studs, a secondary layer of insulation is done over the entire wall in the same material before the plasterboard goes on. Is this the best technique as it will add some significant cost to the build I would imagine, or a cheaper alternative I haven’t seen yet?

- For the floor, it is currently a concrete slab. I’m not sure if it has a DPM under it so I was planning on placing another on top (again, recommendations on best product please). Then I was looking at adding a layer of something like Kingspan and then tongue and groove chipboard on top of that, glued together to make a floating floor.

- For the ceiling, is the best method to use insulating plasterboard and then just standard loft insulation on top? Or as for the walls cover the whole thing in a layer of insulation board before the plasterboard goes on.

I’m sure I’ll have many questions as I go along but for now finding the best materials to use and the correct technique to get the best sound proofing will be a good start.

As for dimensions, the room when split will be about 3 x 2.5m.

Budget wise, if possible I’d like to keep it under £2k. Is this a reasonable budget for what I’m wanting to do?

Thanks

 

[noseall]

- Stud wall splitting the garage in half with a door. Insulated plasterboard both sides with insulation on the inside (Need advice on the best insulation to use for the best sound proofing. Seen either Kingspan or Rockwool get mentioned. I did notice places like B&Q have their own cheaper versions. Are these as good?)

You only need insulate one side of the stud wall. Use 100mm Kingspan between studs and another 50-75mm across the studs on the garage side. Fix two layers of fire-line board on the garage side and 12.5mm foil back board on the habitable side. Foil tape the Kingspan on the habitable side prior to fixing the boards. Fix some broad DPC or DPM to the underside of the sole plate stud before fixing it to the floor. Fire-door, fire-door frame, intumescent strips, fire rated hinges and closer etc for the aperture.

- Stud walls on the three single brick garage walls. I was going to line the back of the stud wall closest to the brick with a DPM (Suggestions on which to go for please). Then again, insulated plasterboard and as above an insulation in between the studs. I’ve seen a technique shown on a lot of videos where after doing the insulation between the studs, a secondary layer of insulation is done over the entire wall in the same material before the plasterboard goes on. Is this the best technique as it will add some significant cost to the build I would imagine, or a cheaper alternative I haven’t seen yet?

As above and yes to lining the wall with DPM first.

- For the floor, it is currently a concrete slab. I’m not sure if it has a DPM under it so I was planning on placing another on top (again, recommendations on best product please). Then I was looking at adding a layer of something like Kingspan and then tongue and groove chipboard on top of that, glued together to make a floating floor.

Sounds like a plan.

For the ceiling, is the best method to use insulating plasterboard and then just standard loft insulation on top? Or as for the walls cover the whole thing in a layer of insulation board before the plasterboard goes on.

300mm Standard glass wool insulation laid in two layers works just fine. 100mm between joists with 200mm across in opposite direction.

Budget wise, if possible I’d like to keep it under £2k. Is this a reasonable budget for what I’m wanting to do?

£2k won't cut it when you consider buying door/frame/ironmongery, insulation, timber, flooring, plasterboards, plasterers, electrics, Building control, decoration etc.


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[Tenatious]

You only need insulate one side of the stud wall. Use 100mm Kingspan between studs and another 50-75mm across the studs on the garage side. Fix two layers of fire-line board on the garage side and 12.5mm foil back board on the habitable side. Foil tape the Kingspan on the habitable side prior to fixing the boards. Fix some broad DPC or DPM to the underside of the sole plate stud before fixing it to the floor. Fire-door, fire-door frame, intumescent strips, fire rated hinges and closer etc for the aperture.

As above and yes to lining the wall with DPM first.

Sounds like a plan.
300mm Standard glass wool insulation laid in two layers works just fine. 100mm between joists with 200mm across in opposite direction.
£2k won't cut it when you consider buying door/frame/ironmongery, insulation, timber, flooring, plasterboards, plasterers, electrics, Building control, decoration etc.


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The electrics are already in and I'm exempt from BR as it is detached and less than 30 square meters so the pricing is only for materials.

What's the reasoning for you saying to put the insulation on the garage side as opposed to inside the room?

 

[noseall]

What's the reasoning for you saying to put the insulation on the garage side as opposed to inside the room?

It affords you better fixing opportunities (habitable side) and creates a 'warm wall' thus reducing any condensation risk.

 

[noseall]

The electrics are already in

Lighting? Switching? Sockets will need moving adding to surely? Extractor?

£2k is still ambitious, but not a million miles off.