A Vapour Control Layer (VCL) is a vital component in modern roof and wall constructions, designed to manage the movement of moisture within a building’s structure. Moisture vapour naturally moves from warm interior spaces toward cooler external areas. Without proper control, this vapour can penetrate the building envelope and condense within insulation or structural elements, leading to issues such as reduced thermal performance, mould growth, corrosion, and long-term structural damage. Installing an appropriate vapour control layer helps prevent these problems by limiting the amount of water vapour that can pass into the roof or wall build-up.
Using a VCL is particularly important in flat roofing systems, where insulation and waterproofing layers must be protected from internal moisture. By creating an effective barrier beneath the insulation layer, a VCL helps maintain the integrity of the roof system, improves energy efficiency, and contributes to the overall durability and performance of the building.
A range of vapour control solutions is available to suit different substrates and installation methods. Products such as ProVap Stik, ProVap Sand, and ProVap TR are designed to provide reliable vapour control across a variety of roof and wall constructions. These systems offer benefits including self-adhesive application for easier installation, reinforced structures for improved mechanical performance, and compatibility with common substrates such as steel decks, timber decks, concrete, and metal surfaces.
Selecting the correct vapour control layer is an important part of roof design and should always be considered alongside the overall roofing specification to ensure long-term performance and protection of the building structure.
PROVAP S/A
PROVAP S/A is a self-adhesive bituminous membrane that forms a barrier against vapour and gases. Consisting of a self-adhesive bituminous compound re-enforced by a composite aluminium foil with integral glass-fibre mat. The upper foil surface is polyester coated offering protection from alkalis and provides a surface on to which LIQUIFLEX PRO and most other polyurethane systems and adhesives will adhere.
The exceptionally high vapour resistance enables use in buildings with extreme internal conditions and high humidity such as sports halls, swimming pools, bathrooms, kitchens and wet industrial processes. Fast and easy installation achieves waterproofing of a roof structure prior to the installation of the insulation and waterproofing, providing a vapour barrier without the need for hot works or naked flame in application.
Suitable for use on most common substrates such as concrete, plywood/OSB and metal decks. The high integral strength of PROVAP S/A withstands puncturing from foot traffic when used on profiled metal decks.
ProVap Stik
The PROVAP STIK Vapor Control Membrane is designed to be used as vapor control layer in flat roofing systems. It consists of a reinforced aluminium foil with self-adhesive coating backing protected by a release film. The self-adhesive coating keeps the membrane in place to facilitate the installation. The UV stabilized polyolefin reinforcement improves the mechanical performance of the membrane. It prevents foot traffic damage and other damage of the vapor control layer over corrugation valleys of lightweight steel decks during installation works. The PROVAP STIK membrane is suitable to be installed on steel deck and wooden deck. It is meant for applications where the roofing insulation is mechanically attached or loose laid. It is not suitable for adhering insulations boards onto. The PROVAP STIK can also be used as temporary protection, please refer to the technical department for specific conditions.
Design and selection of an appropriate vapor control layer is the responsibility of the specifier.
ProVap Sand
PROVAP SAND S/A is a premium grade self-adhering composite membrane used in flat roofing as a vapour control layer and liquid roofing carrier membrane. An SBS polymer modified bitumen compound is laminated onto a tough fibre reinforcement. The top surface is granulated to provide an anti-slip surface.
PROVAP SAND S/A is applied on PROVAP SA Primer to achieve the strongest adhesion to the substrate. Fast and easy installation achieves waterproofing of a roof structure prior to the installation of the insulation and waterproofing, providing a vapour barrier without the need for hot works or naked flame during application.
Suitable for use on most common substrates such as concrete, plywood/OSB and metal decks. The high integral strength of PROVAP S/A withstands puncturing from foot traffic when used on profiled metal decks.
ProVap TR
PROVAP TR is a lightweight reinforced LDPE film with 81% light transmission and good flexibility. The woven polyethylene reinforcement provides good resistance to tears and punctures.
The PROVAP TR standard is used as a vapour barrier within roof and wall constructions.
Also used to temporarily cover openings in the building during construction or as a dust wall.
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