Crawl Space Moisture, Condensation and Humidity Problems

Several years ago, before nearly every home had air conditioning, homeowners opened windows for fresh air, which reduced crawl space moisture, condensation, and humidity problems. Homes are designed to “breathe,” moving air toward the roof and out through the roof vents. Would it surprise you to know that nearly 40% of the air in your first-floor living area comes from the crawl space? The air from the crawl space is pulled into the living area by this natural vacuum, and then it either exits from open windows or it continues toward the roof as the warm air rises. As this air escapes through the roof, it pulls more air from the crawl space, and the cycle continues.

Another way that crawl space air enters the living area is through a home’s HVAC ductwork. Each time the furnace comes on, the air in the crawl space is pulled into these ducts (which are most often in the crawl space) where it then flows throughout the home. The moving air in the ducts creates a vacuum at the seams, pulling the contaminated air from the crawl space and mixing it with the warmed/cooled air. This mixture of air is then delivered to each room in the home. For homes without a forced air heating/cooling system, the percentage drops.

Moisture

An exposed dirt floor in a crawl space is a significant source of moisture, and it is only enhanced by high summer humidity entering through foundation vents and gaps in the rim joist and sill plate. Research indicates that air moisture is constantly exchanged between the outside and the crawl space, meaning the interior moisture level will always mirror the exterior level, regardless of whether the metal foundation vents are open or closed.

The install of a vapor barrier will prevent moisture from entering the crawl space from the ground. Installing a vapor barrier allows for the elimination of foundation vents altogether. Additionally, installing insulation will significantly reduce moisture penetration at the rim joist and sill plate. These installations, along with the elimination of vents, are the first steps in providing your home with a healthy conditioned crawl space®.

Humidity

High levels of humidity create many problems for a home. Wood-boring insects like the powder post beetle, the termite, and the carpenter ant need high moisture to survive and reproduce. Condensation, resulting from high humidity along with extreme temperature changes, can do major damage to a home’s floor joists and wood beams. High humidity also allows mold, fungus, and bacteria to survive and reproduce under a home. The EPA has reported that these conditions can cause or worsen allergy problems, asthma, respiratory problems, and sinus infections.

The Solution

Creating a properly conditioned crawl space utilizing the process of Crawl Space Encapsulation® would be the most effective solution to these problems. Crawl Space Encapsulation® eliminates common problems like moisture, mold, insects, and structural rot. The process’s conditioning relies on three key components:

1. Vapor Barrier: A durable, high-quality, reinforced, polyethylene vapor barrier, such as Guardianliner® or Silverback®, is essential.
2. Water Control (If Needed): A quality sump pump kit with drain tile installed around the interior perimeter for water control.
3. Moisture Control: A dehumidifier or integrating the crawl space with the home’s existing heating and cooling system controls the residual moisture that seeps in through the sill plate and rim joist.

The process also offers more than the eye can see, literally. Crawl Space Encapsulation® can address and resolve many other conditions such as exposure to soil contaminants. For example, the sump basin produced by our company and recommended for use in the process has a completely sealed lid and is certified for radon control. Therefore, if you have a radon problem or are concerned about radon, our solution helps to eliminate this issue.

In addition to the basin, our company’s vapor barrier also serves as an air/gas barrier and has actually been used in the asbestos and mold abatement industries. It is also worth pointing out that the use of our vapor barrier by professionals working with hazardous materials and their confidence in our product’s strength, durability, and performance should certainly stand as a testament to our vapor barrier’s quality and effectiveness that all buyers can expect.

Crawl Space Encapsulation® can also offer savings on your energy costs. This is one of the primary reasons the old building code was modified to allow for a conditioned crawl space. Though it may seem more costly to condition the crawl space, it actually more than pays for itself in the long run because by closing the vents and placing insulation on the rim joist, this is keeping out the cold and/or moist air that absorbs the conditioned air homeowners pay for each month.

When the crawl space is properly conditioned, it will pass any inspection. The end result is clean air with no source of contamination coming from the conditioned crawl space. This, added to the value of the other positive effects of encapsulation, results in a home that is healthy, efficient, and more comfortable.