• A vapor barrier is a plastic tarp, generally at least 6 mil thick, that is laid on the ground floor in the crawlspace. Its purpose is to keep moisture from the ground from rising into the crawlspace. The plastic barrier should be laid so that the large majority of the crawlspace is covered.
• Building codes in most places now require a vapor barrier in new construction. If you have an older home or live an area where it is not required, it is still advisable to have one put in. Over time, this plastic can be shifted or torn if it is moved around too much by people having to work in the crawlspace. It should be checked every few years to see if areas need to be replaced.
• Vapor barriers are fairly simply to install and can be done by most individuals willing to spend some time in the crawlspace. Most local hardware stores will carry the plastic that needs to be spread out in the crawlspace. While not hard, it can take a little time to spread it out depending on how shallow the crawlspace is and how many obstructions there are.
• ATMOX highly suggests that every crawlspace should have a vapor barrier put down as a first step to solving moisture problems in a crawlspace. Further steps should then be taken to control the environment in the crawlspace.