Cleanspace is more than a vapor barrier. It’s actually an engineered film. It is also a seven layer sandwich of high density and low density polyethylene, and polyester cord reinforcement that allows it to be mechanically fastened to the walls and not pull off or tear when someone crawls across the liner. All CleanSpace is made with an antimicrobial additive called ultra fresh, which is a preservative to help the CleanSpace last for years and years. It also has UV inhibitors and stabilizers so the liner does not erode and break down prematurely.