H
hardyspicer
Guest
I want to insulate the ceiling of my attic which I'm going to convert. I have a tile roof, breathable membrane and rafters that are 100mm thick. I'll be able to put insulated plasterboard on the inside but the pitch is low so I'll only be able to use about 30mm of plasterboard.
My main question is what is the maximum amount of rigid insulation I can use between the rafters given that the membrane is breathable? Could I use 75mm? I know you're supposed to leave a 50mm air gap if you use felt but it can be less with breathable membrane. I'm hoping to use something like Kingspan TP10 board. Thanks.
My main question is what is the maximum amount of rigid insulation I can use between the rafters given that the membrane is breathable? Could I use 75mm? I know you're supposed to leave a 50mm air gap if you use felt but it can be less with breathable membrane. I'm hoping to use something like Kingspan TP10 board. Thanks.
