Paraseal® GM is a sheet waterproofing and methane-mitigating membrane consisting of 20 mils of HDPE and expandable, granular bentonite. The composite weight of the material is up to 1.0 lb/ft², creating a dual waterproofing system. The HDPE extends beyond the bentonite on the perimeter edges to create a clean surface for Para JT Tape and Parastick ‘n’ Dry Tape installation.