Flexible moisture relief roof strip underside coating - has elastic perforated outside layer for all round pressure relief

摘要

As used esp. for covering roof structures subjected to moisture, a length of roofing material consists of a sealing length with a coating of flexible porous vapour-expansion material on its underside. This coating (2), at least 2 mm. thick, is provided with an elastic perforated outside layer (3). The two may be perforated at equal intervals. The outside layer can be a highly elastic foil sheet, while the vapour relief layer is of loose textile or similar, or of open-celled foam material, or a fibre strip layer. Using the simple cold-cementing laying process, this permits relief of moisture or air pressure on all sides, and prevents thermal or mechanical tension in the length of material.