Visqueen Fully Bonded Vapour Barrier is an AVCL (air and vapour control layer) 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.