There is an old-fashioned belief still supported by some building codes and general contractors across the U.S. concerning crawl spaces. The belief that crawl spaces should be vented is greatly contributing to the problem of damp, moldy and decaying crawl spaces becoming a true housing epidemic.

According to this belief, crawl spaces need to be protected from ground moisture by the way of a ground vapor barrier (usually a 6 mil plastic sheet) and should be allowed to “breathe” through open vents. This belief says that open vents will dry out the space by allowing outside air to circulate within the crawl space.

It may sound like it makes sense; after all, air is known to dry things. A breeze will dry the clothes on a line and opening a window in the house will help dry out your freshly shampooed carpet, right? However, in a crawl space environment things work a bit differently that they would in open air or at the above floors. Read the rest of this entry »