Coretex is a unique low permeable, hydrophilic waterproofing product that utilizes an Active Polymer Core (APC) technology that is less permeable and more chemically resistant than traditional active waterproofing membranes. It works by forming a low permeable membrane upon contact with water. When hydrated, unconfined Coretex can swell many times its dry volume. When confined under pressure from backfill or concrete, the swell is controlled, forming a dense, impervious waterproofing material. Its swelling action can self-Seal small punctures and cuts in the product resulting from installation activity.