Radon Block™ is a seven-layer co-extruded barrier made from state-of-the-art polyethylene and EVOH resins to provide unmatched impact strength as well as superior resistance to gas and moisture transmission. Radon Block is a highly resilient underslab/vertical wall barrier designed to restrict naturally occurring gases such as radon and/or methane from migrating through the ground and concrete slab. Radon Block is more than 100 times less permeable than typical high-performance polyethylene vapour retarders against methane, radon and other harmful VOCs. Radon Block is one of the most eff ective underslab gas barriers in the building industry today, far exceeding ASTM E-1745 (Plastic Water Vapor Retarders Used in Contact with Soil or Granular Fill Under Concrete Slabs) Class A, B and C requirements. Available in a 20 (Class A) mil thicknesses designed to meet the most stringent requirements. Radon Block is produced within the strict guidelines of an ISO 9001:2008 Certified Management System, and has been evaluated and approved (CCMC 14024-R) as a code alternative solution.