Bison Roofing Underlay is a P-labeled non permeable water diverting underlay of reinforced high density polyethylene, which is coated with low density polyethylene on both sides. The material is UV and alkali stabilized. Bison Roofing Underlay fulfills the requirements of stepping through protection in roofs and floor structures.
Bison Roofing Underlay is air and vapor proof. Mounting is done in parallel or perpendicular to the roof. The distance between the rafters must not exceed 1500 mm. The roof pitch should be at least 14˚.
Bison Roofing Underlay is used as a water diverting layer beneath the roof. It leads out unwanted condensation and eventual rain water that made their way into the roof. This prevents moisture from entering the structure.
Weight: ca 145 g/m2
Width: 1,36, 2,73 & 3,67 m
Length: 25, 50 & 100 m
Water vapor resistance: >1,5x10⁶ s/m, sd-value >40 m
Tear strength: MD: 600 / CD: 600 N
Tensile strength: MD: 15 / CD: 15 kN/m
Elongation: MD: 15 / CD: 15 %
Water tightness: Tight at 200mm water column
Stepping through test: >2,2 kN
Bison Flex Tape, Butyl tape