The climate in the Carolinas is often extremely humid throughout much of the year. This can make it very difficult to control the relative humidity in your crawlspace. Long periods of elevated relative humidity will eventually lead to mold issues and a loss of structural integrity in your crawlspace. Sealing your crawlspace not only reduces odor issues, creates a more energy efficient home, and gives you a clean crawlspace; most importantly it will control the relative humidity levels and reduce them by an average of 20 percentage points. Controlling the humidity and air quality is important not only to prevent structural issues but approximately 40 percent of the air in your home has originated from the crawlspace.
The National Center for Energy Management and Building Technologies conducted field tests of the moisture control effectiveness of crawlspace encapsulation in 2007 and 2008. The field tests were conducted in two separate weather climates; Baton Rouge, LA (very humid climate) and Flagstaff, AZ (dry climate). In regard to moisture and humidity control all field tests showed significant reduction in humidity and moisture in the crawlspace.
The field tests in Baton Rouge, LA and Flagstaff, AZ had a control group and a test group. The control group were standard vented crawlspaces. The test group were made up of encapsulated crawl spaces with use of a dehumidifier.
The Baton Rouge control field tests had humidity levels that averaged 80 percent for most of the spring and summer months. The encapsulated crawlspaces were able to keep the relative humidity to a daily average of 60 percent. Mold growth starts to present itself with extended periods of humidity levels higher than 60 percent.
The encapsulated crawlspaces had just as drastic of an impact in a dry climate as they did in the humid climate. The crawlspaces in the control group of Flagstaff, AZ had an average relative humidity just under 70 percent. The encapsulated crawlspaces had average humidity readings of 50 percent during the same time of year and similar conditions.
Based on the extensive field tests conducted by the National Center for Energy Management and Building Technologies we are finding a drop in humidity of roughly 20 percent.
A quick reference of the benefits of closing your crawlspace:
- Improves air quality throughout the home
- Prevents mold and wood decay in your crawlspace
- Saves 10 percent to 15 percent on heating and cooling costs in the Carolinas
- Reduces buckling of hardwood floors
- Reduces pest and termite issues