Visqueen Fully Bonded Vapour Barrier is an air and vapour control layer (AVCL) and is used in high condensation risk buildings, or where a fully bonded vapour barrier is required to reduce the risk of interstitial condensation occurring within the structure as well as improving the airtightness of the building.

The barrier restricts the passage of warm, moist air within the building from permeating into the floor, wall or roof structure.

The barrier is designed to be installed to the warm side of floors, walls and roofs. It is suitable for all BS 5250:2021 humidity classes including those with high internal humidities e.g. laundries and swimming pools.

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• Approvals and Standards
• System Components
• Preparation
• Installation
• Usable Temperature Range
• Additional Information

Approvals and Standards

• Air leakage to BS EN 1026:2016
• CE UKCA UKNI Mark EN 13984:2013
• Quality Management System ISO 9001:2015
• Occupational Health and Safety System ISO 45001:2018
• Environmental Management System ISO 14001:2015

System Components

• Visqueen HP Tanking Primer, 5L
• VisqueenPro Single Sided Vapour Edge Tape, 150mm x 15m

Preparation

Ensure surfaces are smooth, clean, dust and moisture free.

The barrier can be cut with a sharp retractable safety knife.

Installation

Visqueen Fully Bonded Vapour Barrier should be installed in accordance with the recommendations of BS 5250:2021 Management of moisture in buildings - code of practice. The barrier should be installed on the warm side of the insulated structure, with care being taken to ensure that all laps, penetrations and abutments are sealed. The membrane should be continuous in order to ensure optimum vapour control performance.

All lap joints in the barrier should be a minimum of 75mm and should be pressed and rollered to form a continuous bond.

Ensure barrier continuity at the junction of horizontal and vertical substrates. Seal abutments with VisqueenPro Vapour Edge Tape applied centrally over the junction. Failure to suitably connect the barrier to other building elements will severely reduce vapour control performance.

Ensure the barrier is not damaged in service due to residual heat from light fittings.

When used as an air and vapour control layer on flat warm roof constructions, the substrate should be primed with Visqueen HP Tanking Primer and allowed to dry prior to barrier application. Long periods of exposure to ultraviolet light will reduce the effectiveness of the barrier. The barrier should be covered by a protective layer immediately after installation to prevent damage from following trades, ultraviolet light, etc.

The barrier should not be subjected to gravity forces (unsupported) such as on the underside of roof decks or the underside of floor structures, and should be suitably mechanically secured to ensure that it remains in position during service.

Usable Temperature Range

It is recommended that Visqueen Fully Bonded Vapour Barrier should not be installed below 5°C.

The barrier requires no additional bonding methods however during cold weather conditions the application of hot air to the self adhesive coating will aid adhesion.

Additional Information

Care should be taken to prevent the AVCL from becoming punctured, stretched or displaced when installing plasterboard or other construction board over the installed AVCL.