Dry and clean crawl space

A lightweight, 6-mil plastic liner is just not strong enough to seal out moisture and humidity in a damp crawl space. Every wet and nasty crawl space needs a quality vapor barrier to protect the wood, building materials, and insulation. Moisture raises the humidity and that leads to rot and mold much quicker than most people expect. If you have allergies, or notice that you get headaches a lot, the crawl space might be a factor.