Insulation options

[petej42]

I have a store room over my attached garage which I would like to insulate. The room will be for a den where I can put a train set.

I have spoken to the local building control and they are happy that building regs are not needed but it couldnt be classes as a living room/ bedroom etc. They did give a bit of advice such as to install fireproof insulation between the garage roof/den floor

I plan to put 100mm pir boards on the flat and pitched parts of the den ceiling and I can maintain a 50mm airgap between the insulation and the pitched part.

My question is, the studs for the vertical parts of he wall are only 95mm deep and are backed with osb, so a 100mm board won't fit,
so I can either attach a 5mm strip to these to make them up to 100mm,
Use 90mm pir and have a 5mm gap between the pir and osb.
Use 100mm fibreglass and pack it down to 95mm.

I would be grateful for any thoughts on the best option or any other suggestions

Pete

 

[noseall]

I have a store room over my attached garage which I would like to insulate. The room will be for a den where I can put a train set.

I have spoken to the local building control and they are happy that building regs are not needed but it couldnt be classes as a living room/ bedroom etc. They did give a bit of advice such as to install fireproof insulation between the garage roof/den floor

I plan to put 100mm pir boards on the flat and pitched parts of the den ceiling and I can maintain a 50mm airgap between the insulation and the pitched part.

My question is, the studs for the vertical parts of he wall are only 95mm deep and are backed with osb, so a 100mm board won't fit,
so I can either attach a 5mm strip to these to make them up to 100mm,
Use 90mm pir and have a 5mm gap between the pir and osb.
Use 100mm fibreglass and pack it down to 95mm.

I would be grateful for any thoughts on the best option or any other suggestions

Pete

If you can put your hands on 90mm PIR use that. Otherwise do some 6mm rippings from a sheet of 6mm ply or knock some strips of 9.5mm plasterboard onto the studs before plaster boarding across the studs. It doesn't matter if there is a wee gap.

The rafter will wick the heat/cold down unless you do another layer of PIR across the rafters.

 

[petej42]

Yeah, thought I might have to add another layer, think I'll probably go for the 90mm pir option. If I can get it cheaper than 100mm, probably nothing much in it. Even though it's not subject to building regs, I want to do it right

 

[noseall]

. If I can get it cheaper than 100mm

I'm not sure you will unless it's a stock item. 100mm will most likely be cheapest for its relative size.