Hi.
I'm in the process on a self build and we are just starting the roof. It's a half dormer. I'm wondering what the best way to insulate the roof area is to minimize heat loss. The rafters will be 7 x 2, which means if I'm leaving a 2 inch air gap on the under side of the roof, I've only got a depth of 5 inches(125mm) for insulation, which I'm concerened is just not enough.
Would I be better increasing the rafter sizes to accomodate more insulation? I had tought of combining a polyiso (xtratherm etc) insulation board with rockwool in the rafters, but to do this I'd need a depth of 50mmm + 100mm + 140mm (air gap + ins. board + rockwool), which is 12 inches. This doesn't seem practical as it eats into the head room of the upper floor.
Has anyone any advice on what might be the best solution to provide high level of insulation without eating into head height space? Any advice would be great.
thanks
dj01
I'm in the process on a self build and we are just starting the roof. It's a half dormer. I'm wondering what the best way to insulate the roof area is to minimize heat loss. The rafters will be 7 x 2, which means if I'm leaving a 2 inch air gap on the under side of the roof, I've only got a depth of 5 inches(125mm) for insulation, which I'm concerened is just not enough.
Would I be better increasing the rafter sizes to accomodate more insulation? I had tought of combining a polyiso (xtratherm etc) insulation board with rockwool in the rafters, but to do this I'd need a depth of 50mmm + 100mm + 140mm (air gap + ins. board + rockwool), which is 12 inches. This doesn't seem practical as it eats into the head room of the upper floor.
Has anyone any advice on what might be the best solution to provide high level of insulation without eating into head height space? Any advice would be great.
thanks
dj01