I need to insulate my loft, and was thinking of using polystyrene batts between the joists (or is it rafters?) on the "floor" of the loft. I have seen nothing that would suggest that I can or can't do this. The only reason I can think of for not using them is that they are very flammable. However, I know that you can spray the inside of the roof with poystyrene, and you can use it between floors and under floors, so presumably flammability cant be a reason for not using it. Polystyrene is a very efficient insulator so I would have thought that someone would have used it if it was permissible. I've just asked an architect friend and he doesn't know the answer to this one. Can anyone help?
