A healthy crawl space is essential for a healthy home. I’ve written about other aspects of crawl spaces before, but this post covers the most important part of a healthy crawl space… the vapor barrier. I recently visited a crawl space without a vapor barrier. As you can see, the ground was bare dirt.
A vapor barrier is normally a sheet of black plastic between 4 and 6 mil thick. If your crawl space has a concrete floor then the vapor barrier is under the concrete, hopefully. It is likely that if your house is older and you have a concrete floor then there is no vapor barrier under the concrete. In this case you should paint the concrete with a good concrete floor paint or epoxy. The paint will help prevent moisture from moving through the concrete and into the house.
If you can see black plastic then you have a dirt or stone floor. Dirt and stone both allow moisture to evaporate into the air.
When installing a vapor barrier, it’s important to secure the vapor barrier to the outside block wall. I recently found this out while crawling around on a vapor barrier. As I crawled around, it pulled away from the walls.
The other important part of vapor-barrier installation is to tape the seams. Taping the seams seals them, preventing moisture from escaping through small openings.
Vapor barrier installation is quite simple and can be accomplished by most home owners. If you can crawl around in small, confined, dark places you should be able to install a vapor barrier. Vapor barriers are carried on the shelves at Lowes and Home Depot.
The vapor barrier prevents moisture in the ground from evaporating into the air. In a crawlspace the moisture coming from the ground can build up and raise the moisture content of the wood framing. High moisture content can lead to insect infestation or mold, or both unfortunately. You can refer to my blog about mold for more information.
Maintaining a healthy house starts with keeping water out. While most people think of leaks when it comes to water problems, air moisture is the main hidden problem for most homes. In a home without active leaks, moisture intrusion from air is the leading cause of water problems. Keep your house dry. Keep your house healthy.