Outside Air
Most dirt crawl spaces are vented to get the moisture out. The problem is that the vents let warm humid air in during the summer. This adds moisture to the crawl space, and makes the house harder to air condition as all this moisture needs to be wrung out of the air. In the winter, the vents let in cold air, which causes very cold, uncomfortable floors upstairs and higher heating coast.
Drainage Matting
A crawl space vapor barrier is an excellent way to keep water and moisture from your crawl space, but it's also important to drain away flooded water that collects underneath.
Mold
Mold loves moisture. And mold loves to eat dead organic materials, like wood, paper, and cardboard. The bad news is most crawl spaces have lots of moisture, as well as wood and other organic materials for mold to grow on.
