Vapour Check is used to omit the risk of interstitial condensation within a structure as well as improving the airtightness of the building. Vapour Check restricts the passage of warm, moist air from within the building from permeating into the structure or the roof. Vapour Check is manufactured using virgin polyethylene. Visqueen Vapour Check provides a means of protecting the warm side of the thermal insulation incorporated in a building by creating a barrier to the movement of warm, moist air. Visqueen Vapour Check is a loose laid membrane designed for use in roofs, walls and floors subjected to humidity levels less than 50% at 15 degrees Celsius (BS5250: 2002 class 1 condition) e.g. warehouses, industrial units and storage areas.