Bison Permeable Roofing Underlay 175 is a breathable roofing underlay. It can be mounted on wood board or directly on the wooden rafters. Please note that the roofing underlay is not stepping through protected. No air gap to the wooden base or insulation is needed. The minimum roof pitch for the roofing underlay is 14 °. Should not be mounted on impregnated wood.
The roofing underlay is used to protect the roof structure from rain, snow and wind. The material allows unwanted internal water vapor to be transported out through the membrane while it is water and air tight from the outside. The good properties as regards to vapor transport help to protect against moisture and condensation problems.
Weight: 175 g/m2
Adhesive edges: 2
Length: 50 m
Width: 1,5 m
Water vapor resistance: ca 0,9x10³ s/m,
sd-value 0,02 m
Water tightness: W1
Temperature resistance: - 40° C - + 100° C
Tear strength: MD: 170 N, CD: 210 N
Elongation: MD: 60%, CD: 80%
Tensile strength: MD: 340 N/5 cm, CD: 230 N/5 cm
Fire classification: E
Bison Flex Tape, Butyl tape