Wet Crawlspace

Crawlspaces are different from basements in many ways.  Other than the fact that they are short and more difficult to access, they also are frequently wet, since they tend to be built when the water table does not allow the depth of a basement.  Stand alone crawlspaces are usually vented to the outside.  And many crawlspaces have dirt floors, which present their own unique problem.

A crawlspace with a concrete floor and vents in the foundation walls is quite common and is usually manageable.  There has to be sufficient ventilation to exhaust moisture that intrudes through the walls or floor slab.  When ventilation is adequate, the space should remain dry.

It is important to note that the outside air will sometimes carry quite a bit of moisture, especially in the summer months and during rain events.  When this warm, moist air enters the crawlspace, it will cool and become even more humid.  Through this process, it is possible to have sufficient humidity to support mold growth even when there is no visible moisture.  Mold needs food as much as it needs moisture, and can be controlled by eliminating food.  It makes sense to avoid the use of susceptible materials such as fiberglass insulation and drywall in a vented crawlspace.


Where there is water intrusion that adds to the moisture level in the crawlspace, two options exist.  These include increasing ventilation mechanically with a Bon Air by Humidex, or managing the water intrusion with a drain and sump system.  Installing the drain and sump in a low crawlspace can be challenging, but works just as well as a system installed in a basement.

Dirt crawl spaces are common in many homes and present unique problems for the homeowner. Dirt inside the home transmits humidity, odors and radon gas.  The humidity and dampness that is inherent in crawl spaces can also cause structural damage to the wood framing, carpets, floors and walls. This environment is a breeding ground for mold, insects and rodents, especially when food materials such as wood and insulation are present.  The soil can present a real problem.

The homeowner might consider pouring concrete over the crawl space floor, but in a post construction setting this is often unrealistic and impractical.   A rugged polymer vapor barrier such as the Basement Technologies Crawl Space Conduit® is the perfect solution for dirt floor crawlspaces.  With three plys of 20 mil high strength polyethylene, the Crawl Space Conduit® essentially acts as a concrete floor replacement.  When sealed securely to all walls, it provides a vapor proof barrier that will reduce humidity and provide a clean, durable floor covering.

When combined with our tried and true methods of dehumidification using The Air Mop® 3 in an unvented space, or the Bon Air by Humidex for a vented space, the Crawl Space Conduit® will reduce moisture infiltration and avoid mold activity in the crawlspace.