How thick should a crawl space vapor barrier be?

A vapor barrier’s job is to seal out moisture, so making sure it’s thick enough to do just that is essential. Big box store liners are typically 6-mil thick. These liners aren’t able to handle the area’s conditions and often rip before installation is even completed.  

We recommend a 20-mil, zero perm liner. Our liner is American-made and comes with a nationally backed, long-term warranty.