We used CleanSpace, our patented 12 Mil low density, high density polyethylene antimicrobial liner, nylon-reinforced for strength, as a vapor barrier on the walls. The CleanSpace is tucked into the WaterGuard (see photo below) so that if any foundation leaks occur in future, they will be channeled to the WaterGuard, ensuring that the living space remains free from water and possible mold, preventing any resultant health issues.