Our roofing membrane is a three layer highly breathable, fully waterproof membrane, constructed from high tensile spun-bonded polypropylene layers, around a microporous PE film. The outer layer forms the functional waterproof surface, the middle layer is the breathable waterproof membrane, and the inner layer protects the membrane from abrasion and damage, also giving additional strength. This enables the fabric to allow moisture vapour to pass through, whilst remaining fully waterproof.