I have been asked to help a friend convert an attic by insulating under a slate roof. The roof is not felted, the slates are in good condition with no leaks. At present it is cold in winter and hot in summer. The rafters have little depth, so the plan is to build a framework underneath to support either plasterboard or t&g pine beneath insulation, either celotex or rockwool, then a 5-8 cm air gap beneath the slates.
My questions are, is a vapour barrier required under the insulation and is anything required above the insulation, especially if rockwool is used, possibly a foil layer to help reduce thermal gain in summer?
My questions are, is a vapour barrier required under the insulation and is anything required above the insulation, especially if rockwool is used, possibly a foil layer to help reduce thermal gain in summer?
