SOPRASEAL STICK VP is a permeable air barrier membrane, primarily used in wall construction to control the movement of air into and out of a building.

Why is there a need for air barriers?

Air barrier systems are the components of the building enclosure that control the movement of air within a building enclosure. They allow wall assemblies to breathe, reducing the risk of structural damage and high energy costs.

Selecting the proper air barrier system can lower energy costs, decrease mould risk, and mitigate any deterioration caused by moisture infiltration. Air barriers are a vital piece in the continuity of the building enclosure.

SOPRASEAL STICK VP is self-adhered to provide an easy, fast and cost-effective installation. Incorporating a vapour-permeable trilaminate polypropylene composite facer coated with a high-tack self-adhesive backing, it is further protected by a release film.

The membrane’s notable features include its width and self-adhesive underface, allowing versatile application on various building surfaces such as masonry, concrete, wood, and gypsum.

How do air and vapour barriers work?

When the indoor temperature exceeds that of the outside air, moisture will move from the interior to the exterior, and vice versa. Remember that water vapor will migrate from the warmer side of the assembly to the colder side.

Without an air or vapour barrier, moisture can infiltrate the assembly.  However, a well-designed and properly installed air or vapour barrier within the assembly prevents moisture from penetrating the wall.

Air barrier membrane or rigid air barrier?

Choose an air barrier membrane for flexibility, easy application, and adaptability, minimising cracking risks. Rigid boards, though providing impact resistance, have limitations like inflexibility, labour-intensive installation, and potential weight issues.

SOPRASEAL STICK VP is a permeable air barrier.

Permeable vs Non-permeable

A permeable air barrier allows water vapour diffusion, while offering resistance against air leaks and water filtration. In contrast, a non-permeable air barrier also resists the diffusion of water vapour and is considered a vapour barrier. A permeable air barrier can be installed on either side the warmer or cooler side of the exterior insulation, whereas a non-permeable air barrier must be installed on the warmer side of the insulation.

Why does vapour permeability matter?

When designing a wall assembly, preventing leaks takes top priority. But if leaks do occur, the wall must be able to dry. While more permeable materials enable faster drying, they also increase inward vapour drive. It’s about finding the right balance.

Contrary to common belief that the highest permeance level is always ideal in an insulated exterior wall assembly, SOPREMA Canada’s research debunks this myth.

According to their findings, low to medium perm membranes are sufficient to maintain appropriate moisture levels in an insulated exterior wall assembly, mitigating the risks associated with high permeance, such as 50 perm, which can lead to condensation and moisture issues. When a building gets wet, it needs to have the capability to dry.
For more information of vapour permeance and SOPREMA Canda’s research see here Choosing the Right Permeable Air Barrier Membrane | SOPREMA | SOPREMA


SOPRASEAL STICK VP-S FR – a self-adhesive vapour permeable air membrane used in wall and roof constructions. It prevents air leakage through the building envelope and allows moisture to escape before causing any material damage to the structure.

SOPRASEAL STICK FLASHPRO HT – air/vapour barrier tape used as a window flashing and for openings and transitions.

SOPRASEAL SEALANT – low VOC elastomeric sealant used to seal details and critical areas.

Technical Data

Key Benefits:

  • Optimum permeability (11 perm [ASTM E96-A])
  • No primer required
  • UV exposure up to 180 days
  • High quality adhesion
  • Self-sealing membrane ensuring continuous waterproofing
  • Service temperature -40 ° to 85 °C

Technical support:

  • On-site quality assurance
  • Certified applicators available nationwide
  • Up to 20 year warranty available

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