Faulty vapor barrier leads to flooding
Dear Angie: The previous owner of my home put down a vapor barrier on top of gravel in our 5-foot tall crawlspace. Twice in the last 2 years, the crawlspace has flooded – 4 ½-feet deep in 2008 and recently 8-inches deep. Now, there is water on top of the vapor barrier. My intuition is to remove the plastic vapor barrier, since it does no good when there's water on top of it. If I replaced the vapor barrier, the next time it floods, it would become useless, because the plastic shifts around and leaves half the crawlspace uncovered. What's the best approach, replace it every time it floods, leave it, or try something else? – Rob G., Carol Stream, Ill.
Dear Rob: You're right. Water on top of the vapor barrier (which helps keep ground moisture from entering the home) is a problem. Neither replacing it each time the crawlspace floods – nor leaving it alone – will solve your problem, though. You need to find the source of the water penetration. Correcting the flooding issue will resolve everything else, and it might prevent some issues you don't have yet, but are certain to come if you don't plug your leak.
Standing water in your crawlspace can lead to serious health issues as a result of mold growth, plus it could cause significant damage to the structure of your home. The source of the water could be from the ground sloping toward your home, rather than away; downspouts discharging water too close to the foundation; the absence of a sump pump and perimeter footing drain system, or a malfunction of those; cracks in the foundation; or plumbing leaks.
A qualified home inspector or structural engineer can help determine your problem and offer recommendations on how to correct it. Once you have eliminated the source of the water, you should ensure the area is dry, have any mold growth remediated or other damage repaired, and then replace the vapor barrier. Adding gravel on top of a new barrier can help hold it in place. Be sure to get estimates from at least three different contractors for any repairs and always check references.