Diffusion-tight underlayment roof

Our underlay roof is a so-called diffusion-tight underlay roof where ventilation is always required under the air gap according to practice or cold attic. It is installed between rafters with a maximum center distance of 1200 mm. The underlay roof is made of a P-marked, aging-resistant, and puncture-protected fabric and is primarily used as a hanging, water-draining underlay roof. This creates a water- and diffusion-tight sub-roof that "hangs" under roof tiles or profiled sheet metal. The film consists of HD polyethylene fabric, coated on both sides with a layer of LD polyethylene. The materials are also heat, UV, and alkali stabilized. Our recommendation is to load the surface with caution and to seal and repair any damage immediately. The underlay roof is approved for Swan-labeled construction.