Bison Permeable Roofing Underlay is P-marked, breathable and stepping through protected. The product is based on the latest technology: Monolithic. The material is mounted below the surface, on top of the rafters. No air gap to the surface is needed, the membrane is mounted directly on top of the insulation.
The Roofing Underlay protects the roof against rain, snow and wind. The material allows internal water vapor to be transported out through the material while it is water and airtight from the outside. The good properties as regards to vapor transport protects against moisture and condensation problems.
The roofing underlay has double adhesive edges, which allows a secure sealing at the overlap. The low weight and the large covering area of the rolls makes installation simple and quick.
Weight: 235 g/m2
Adhesive edges: 2
Length: 25m & 50m
Width: 1,5 m (up to 3 m is possible)
Water vapor resistance: 4,3x10³ s/m, sd-value 0,11 m
Water tightness: W1
Water column: > 4 m
Temperature resistance: - 40° C - + 90° C
Tear strength: MD: >250 N, CD: >250 N
Elongation: MD: 55%, CD: 60%
Tensile strength: MD: 320 N/5 cm, CD: 470 N/5 cm
Fire classification: E
Bison Nail Tape, Butyl tape