Procheck® A2, is a vapour and airtight membrane. Procheck A2, with it’s Class A2-s1,d0 fire classification to BS EN 13501-1, is considered non-combustible with no contribution to fire. Its composition comprises of the glass fibre backing, with a pure aluminium foil and clear lacquer coating. This composition affords the membrane its Class A2 performance as well as giving it a high degree of vapour controlling properties. The membrane comes with a high vapour resistance, as well as being airtight, which allows its use as an AVCL in the construction. Providing high levels of airtightness can ensure the thermal efficiency of the building.