The Corotop® X-tream a three-layered highly vapour- permeable polypropylene roof membrane. The product can be used on fully boarded heat-insulated pitched roofs. It is a membrane of high strength parameters resistant to mechanical damages, which makes the assembly of the product more comfortable. The product is resistant to ultraviolet radiation, thanks to the application of technologically advanced lamination (termo- bonding), the membrane is resistant to aging. Consequently, its parameters do not change over time what guarantees the durability and reliability of the initial covering of a roof.