Liabilities of Vented Crawl Spaces And Their Impacts on Indoor Air Quality in Southeastern U.S. Homes

This study documented that houses in the southeastern United States built on typical wall ventedcrawl spaces possess the following characteristics: 1) liquid water, water vapor and associatedmoisture issues, 2) mold spores, 3) measured holes between the crawl space and living space, 4)measured transmission of mold spores from the crawl space to the living space. When thesecharacteristics exist together, the study indicates that contaminants (mold spores and moisturevapor) present in the crawl space are being transmitted through holes in the house floor andheating, ventilation and air conditioning (HVAC) system into the livable parts of the home,thereby exposing occupants to potentially harmful crawl space contaminants. These resultsconfirm vented crawl spaces as important sources of mold species in the home environment. Inorder to reduce this exposure, closed crawl spaces in combination with thorough house and ductair sealing should be implemented. Such a system was found to be a robust intervention thatreduced the moisture and indoor air quality problems associated with typical wall vented crawlspaces.