Non warping foamed plastics roof insulating panel - has coating of preferably bitumen saturated crepe paper

摘要

The roof insulating panel is made of foamed plastic material (1) with a continuous flexible covering layer, at least on its upper side, intended to avoid warping, in the form of a bulge when exposed to solar radiation or other forms of heat. This covering layer is made of crepe paper (2). This may be saturated in bitumen. The liability to warp and bulge is checked by transferring the shrinking effects to the corrugations in the paper, and no tension generated in the covering layer.