Creating a Waterless Crawl Space

The majority of houses in the United States have crawl space type foundations that have moisture or water in them due to poor moisture management.  How do you know if you have moisture in your crawl space?

There are several symptoms that can indicate a moisture problem.  They include musty odors and/or high humidity in the living area, buckling hardwood floors, wooden frames that are rotting, insect infestations, condensation on water pipes, condensation on insulation, condensation on air conditioning ductwork, and mold in the crawl space.

It is sometimes easier to detect these things during the hotter months of spring and summer; however, they can occur at any time of the year.   Most of these consequences can be easily corrected by appropriately waterproofing your crawl space.

Although for many years it has been widely believed that outside air ventilation to a crawl space is the best way to keep moisture levels in control, this is not necessarily the best method during the more humid seasons.  There are now new more effective ways of keeping moisture out of basements and crawl spaces that also have the ability of increasing the overall energy efficiency of homes.

The biggest component to preventing moisture is a crawl space vapor barrier.  A vapor barrier is made up of a high tensile strength material that is 10-20 mils in thickness.  Crawl space vapor barriers are puncture resistant and are capable of completely preventing moisture from the soil under the crawl spaces from entering the area.  

Similar to swimming pool liners, the crawl space vapor barrier can be used to encapsulate an entire crawl space even up the foundation walls.  This allows it to protect against the formation of mold and mildew on exposed wood and also improves the indoor air quality and humidity levels inside the house.  

In addition to installing a crawl space vapor barrier, it is important to stop any water permeation through the walls of the foundation that is below grade.  There are different ways of accomplishing this, based on individual circumstances.

Waterproofing a crawl space may entail the excavation and sealing of exterior foundation walls and the installation of an interior or exterior French drain tile system used to direct water out and away from the crawl space and foundation.  

To complete the waterproofing of your crawl space, you will want to seal it.  Contrary to air ventilation, recent studies are showing that a properly sealed crawl space provides for better house health and efficiency, cleaner air and a nice, dry crawl space that can even be used for storage.  

Sealing your crawl space stops the outside humidity from coming in and settling in the crawl space, promoting mold growth and condensation and basically will eliminate humidity fluxes altogether.

There are many benefits to creating a water-free crawl space.  With the use of a vapor barrier and the other techniques recommended, you can have a completely dry crawl space that helps reduce energy costs, protects against pests, radon, moisture and mold, provides extra storage and will ultimately save you money.