Bison Permeable Roofing Underlay

Material
Bison Permeable Roofing Underlay consists of polyester coated with polyurethane. The material is UV and moisture/heat stabilized. The material is of the latest technology: Monolithic. There are many advantages to Monolithic technology. The improved watertightness is one of the benefits. IQD 128 means the product is third-party audited, ensuring quality over time.

Product description
Bison Permeable Roofing Underlay is an open to diffusion and trample-proof roofing underlay. The roofing underlay is installed free-hanging under the surface layer, on top of the roof trusses. There is no need for an air gap against the surface; the membrane is laid directly on the insulation. The minimum permitted roof pitch is 14°. The roofing underlay can be freely exposed for a maximum of 2 months. If the roof is not installed immediately or if a surface that lets in a lot of water is used (e.g. clay tiles, slate), Bison Nail Tape is recommended under the counter battens. The roofing underlay is used together with surface layers of e.g. roof tiles or profiled sheeting. It cannot be used together with bitumen based surface membrane. (the roofing underlay also work on wooden roofs made of e.g. tongued and grooved board.)

Function
Bison Permeable Roofing Underlay is used to protect the roof structure from rain, snow and wind. The roofing underlay allows unwanted internal water vapor to be transported out through the material while being water and airtight from the outside. The good vapor transport properties of the roofing underlay help to protect against moisture and condensation problems.

Benefits
Bison Permeable Roofing Underlay has double adhesive edges, which allows for more secure sealing in case of overlap. The low weight (approx. 215 g/m2) and the large surface area of the rolls make installation quick and easy. Since the roofing underlay is open to diffusion, ventilation in cold attics can be omitted. The attic space is then ventilated in the air gap instead.

Storage
Bison Permeable Roofing Underlay is stored in unopened packaging or so that it is not exposed to moisture, heat or UV light. The roofing underlay should be prestored at >5° C for optimal adhesion of the adhesive strips.