Fungal contamination of building materials, especially sheetrock and ceiling tiles, is common following moisture damage. Compounds that can prevent fungal growth would be useful pretreatments during for the manufacture of these materials. The Aerobiology Lab has recently tested a novel compound for this purpose. The compound is described as catalyst altered water and has a pH of approximately 12.63. Cellulose-based acoustic ceiling tiles and gypsum-based sheetrock were cut into 36 cm2 squares. Ceiling tile squares (CTS) and sheetrock squares (SRS) were sterilized by autoclaving for 25 min at 121 C. CTS and SRS were saturated with sterile distilled water or various concentrations of the test compound. Saturated materials were inoculated with 10 l of a spore suspension of fungi commonly isolated from buildings including Stachybotrys chartarum, Cladosporium cladosporoides, Aspergillus versicolor, Alternaria alternata, and Penicllium sp. Fungal growth was measured weekly for 4 weeks. In addition, spore germination experiments were conducted in 96-well microtiter plates. Results showed that the test compound was effective in preventing fungal growth on ceiling tiles and 75% solutions inhibited spore germination. CTS were also soaked in the test compound, dried, and stored for varying periods of time to simulate the use during manufacturing. The treated tiles were later saturated with distilled water and inoculated with spore suspensions. Fungal growth was inhibited on the treated tiles. By contrast, the test compound was not effective on sheetrock. This was possibly due to the buffering capacity of the gypsum. Results suggest this compound may have some effectiveness in the ceiling tile industry.