Product examples
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Accessories
Bison Flex Tape Pro
Bison House Wrap / House Wrap Pro, Bison Permeable Roofing Underlay and Bison VCL are developed to form an open to diffusion system of air- and watertight membranes.
How it works
The BisonSystem achieves good air and water tightness in wall and roof constructions. You get a so-called bidirectional vapor transport, which is the basis for energy-efficient living and a healthy indoor climate.
Bison House Wrap / House Wrap Pro Pro, Bison Permeable Roofing Underlay and Bison VCL are developed for the Nordic climate. The membranes are registered for third-party audited quality control (IQD128). Together they form an open to diffusion system of air- and watertight membranes. This results in a so-called bidirectional vapor transport, which allows built-in moisture to dry out faster. The BisonSystem achieves good air and water tightness in wall and roof structures, which is the basis for energy efficient living and a healthy indoor climate.
Wall construction: Bison House Wrap/House Wrap Pro – Bison VCL
By using Bison House Wrap/House Wrap Pro on the cold side and Bison VCL on the warm side, an optimal open to diffusion relationship is formed. This results in a ratio of (at least) five times as tight foil on the inside compared to the outside, which corresponds to the guideline in wall constructions. This construction ensures that the wall is protected from moisture and wind while allowing any construction moisture to dry out.
Roof construction: Bison Permeable Roofing Underlay- Bison VCL
In roof constructions, Bison Permeable Roofing Underlay can be combined with Bison VCL and an optimal open to diffusion ratio is achieved. This results in a ratio of (at least) ten times as tight foil on the inside compared to the outside, which corresponds to the guideline in wall constructions. This construction keeps the roof water- and windtight while allowing any construction moisture to dry out.
Why open to diffusion Roofing Underlay?
With Bison Permeable Roofing Underlay, there is no need for an air gap to the surface; the membrane is laid directly against the insulation. The light weight means that more square meters can be accommodated in the roll, which in turn generates fewer splices. The rolls are easy to transport and are not as bulky as bitumen-based roofing underlay. Bison Permeable Roofing Underlay does not require constructions with openings at the eaves and ridge as the membrane itself can transport moisture away.
Why VCL (Vapor control layer)?
There are many advantages of using Bison VCL compared to using a sealed vapor barrier on the inside of the structure. For example, the risk of moisture from the construction phase leading to moisture damage is minimized. The VCL is well suited to most constructions but is particularly advantageous for holiday homes/seasonal homes/garages where heating takes place periodically. The VCL also combines particularly well with natural fiber insulation/cellulose insulation (organic material insulation). VCL is also well suited for wet room exterior walls to avoid double sealing layers.
Important to seal!
In order to achieve good airtightness and moisture safety in wall and roof structures, the joints and penetrations of our membranes should be sealed with our jointing aids. Use our ageing-resistant Bison Flex Tape Pro for sealing joints, penetrations or for minor repairs. Where a double-sided function is required: use our age-resistant and double-sided butyl tape: Bison Butyl Tape.