A small building built to residential code was flooded using farmland pond water to a depth of two feet at Tuskegee University. The building was drained and left enclosed for an additional three weeks. A total of 168 material samples were removed either immediately after opening (wet) or seven months after flooding (dry). Wall materials sampled included fiberglass batt insulation, gypsum wallboard, wood stud, plywood panels, vinyl siding, and house wrap and were analyzed by cloning and sequencing to identify the mold species present both above and below the water line. The vinyl siding and house wrap had the lowest mold growth while the batt insulation had very high quantities of mold, followed by the paper siding of the gypsum. The common types of molds present included Aspergillus, Chaetomium, Fusarium, Trichoderma, and Stachybotrys. The different molds were analyzed for presence on the different types and components of wall materials in areas exposed above and below the water line. In addition, real-time PCR quantitated selected mold species on different building materials. The mold species found in the highest concentration were Aspergillus fumigatus, Paecilomyces variotii, Chaetomium globosum, and Stachybotrys chartarum. The batt insulation supported the highest concentration of mold after flooding, followed by the wood stud, plywood sheathing, and gypsum wallboard. The highest level of mold on the dry materials was Aspergillus fumigatus on the dry wood stud and Stachybotrys chartarum on the dry gypsum. The focus of the research was to show that flood waters can penetrate into wall cavities of a home and the different wall materials become a substrate for different molds to develop, which potentially cause problems for some susceptible individuals.

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