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The side with print should be inwards (towards the warm side).

Yes

Yes

The VCL is suitable for all houses where you want a more forgiving construction that can breathe. The properties are particularly suitable for, for example, holiday homes / seasonal accommodation where heating takes place periodically.

In cold-storage structures, there is a risk that the outdoor temperature is significantly warmer than the indoor temperature. For example, during spring and fall. This can lead to condensation in the walls of the building. The vapor control layer then allows the moisture to migrate inwards and then be ventilated away, instead of the moisture remaining in the wall. This avoids moisture being trapped in the structure. An open to diffusion design allows moisture to dry out in two directions.

A vapor control layer is airtight but vapor-open. It is therefore possible to achieve the same good airtightness as a vapor barrier while allowing a certain amount of vapor to pass through. In a permeable construction, this means reducing the risk of trapped moisture in the ceiling or walls. Vapor transport is bidirectional, which means that any moisture can be transported in both directions.

Thermal insulation (e.g. cellulose-based) is hygroscopic, which means that it can absorb and release moisture. The vapor control layer then allows any moisture to be transported out of the structure.

Vapor control layer is recommended to avoid two dense layers when the bathroom is placed against an external wall. By using a vapor control layer instead of a vapor barrier, it is possible to have two layers of waterproofing in the wall construction. Any moisture is then not trapped between two dense layers, but can instead dry out through the vapor control layer, which allows a certain amount of vapor transmission.

Variable vapor control layer can in some cases allow compact roof structures without air gaps. Allows for extra effective drying in summer as the membrane opens at high relative humidity.

The printed side should be outwards (towards the cold side).

We recommend a maximum of 1 month.

We recommend a minimum 22mm air gap between the foil and the outer panel.

We recommend a maximum of 3 months (Approved as temporary weather protection).

We recommend at least 22mm air gap.

In the case of a low roof pitch and/or when the roofing underlay is open for a long time before the roof is installed.

Usually installed between nail battens and roofing underlay (e.g. Bison Permeable Roofing Underlay or Bison Permeable Roofing Underlay 175).

Our trample-proof roofing underlays:
Bison Roofing Underlay (Diffusion tight)
Bison Permeable Roofing Underlay (Open to diffusion)

Yes

No, not when it is free-hanging directly on the roof trusses.

Yes, the foil is diffusion tight and therefore requires air gap.