RIW Sheetseal GR is a cold-applied sheet membrane combining a high density polyethylene film bonded to aluminium foil with a bitumen/rubber self-adhesive layer and a removable reinforced silicone release paper. This multi-layer construction delivers both a robust waterproof membrane and a tested barrier against methane and carbon dioxide gas — making it the product of choice where ground gas is a concern alongside water ingress. The product has been independently tested by Wimpey Laboratories for methane gas resistance, with results documented in the product data sheet. When correctly applied, Sheetseal GR provides Type A (barrier) protection capable of meeting the requirements for Grade 1, 2 and 3 basements as classified in BS8102:2009. Benefits Factory controlled thickness ensures consistent performance Selvedge strip to improve lap sealing Elastic and flexible Water and water vapour barrier Methane and carbon dioxide barrier Self healing Good to know Subject to normal conditions of use Sheetseal GR will provide an effective barrier to methane gas, water and water vapour for the life of the structure No drying time Sulphate resistant