Generally nasty conditions in a crawlspace

In the top left corner you will see an open vent, these are great for letting the humid summer air into the crawlspace. The insulation then soaks up the moisture and sags or allows mold to grow. On the ground you will see a shabby thin plastic liner. This liner does very little to control humidity and water. It is basically a way to keep your knees semi-clean when crawling around.