I am currently restoring an old house and did an extension. I made a dormer type house of it and need to insulate upstairs. I have only 4 and a half inch rafters in the old part and six inch rafters in the new. so i was wondering how to insulate the slopes. I mentioned to the engineer that i would use the foil insulation and 1 inch battens and he said this was fine if i used the foil that conforms to regulations (SUPER 10 ,I think he mentioned) . But from reading other threads i am under the impression that no foil insulation covers building regs. I would appreciate your replys.