Warming the attic, We place mineral or glass wool thermal insulation boards between the rafters. From the inside of the room, it is absolutely necessary to cover it with sheets of vapor barrier made of PE polyethylene foil. The foil strips are always placed at least 10 cm pleats, and then sticks a sticky tape on the lap line. We need to get a very tight layer, which does not allow water vapor to pass from inside the room to the thermal insulation, sensitive to moisture.