Paraseal GM/LG 20 Mil

HDPE/Bentonite Sheet Membrane Dual Waterproofing System

Paraseal® GM/LG – 20 mil is a sheet waterproofing and methane-mitigating membrane consisting of 20 mils of HDPE, expandable, granular bentonite and a protective layer of spun-bonded polyester. 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.


  • Paraseal GM/LG – 20 mil is designed for use in post-installation submerged conditions, on blindside walls, and under slab where hydrostatic water head and/or methane conditions exist
  • It may also be used on backfilled walls