Newly built vaulted tiled roof using breathable membrane. Rafters are 145mm deep.
I intend to use 100mm celotex between rafters (leaves air gap of 45mm). Will then put 25mm celotex under rafters. Does this sound OK?
I dont get the need for the air gap? If warm air gets through the insulation, surely it will pass straight up through the membrane. I have no soffit vents so what is the purpose of the air gap?
Should I install soffit vents? I was advised these are no longer required when using breathable membrane. If this is tru what is the purpose of air gap as air doesnt vent anywhere apart from up through membrane?
Thanks guys
I intend to use 100mm celotex between rafters (leaves air gap of 45mm). Will then put 25mm celotex under rafters. Does this sound OK?
I dont get the need for the air gap? If warm air gets through the insulation, surely it will pass straight up through the membrane. I have no soffit vents so what is the purpose of the air gap?
Should I install soffit vents? I was advised these are no longer required when using breathable membrane. If this is tru what is the purpose of air gap as air doesnt vent anywhere apart from up through membrane?
Thanks guys
