Mold growth on building materials is a major problem for homeowners. The most suitable method to control mold growth on building materials is to utilize design features, construction tools and practices that prevent moisture accumulation, and keep the wood as dry as possible. In order to achieve this, engineers and homebuilders have to know the effects of various temperature and moisture conditions on water accumulation and drying speed of various building materials, and the rates at which mold grows in a particular environment. A study was recently conducted at FPInnovations-Forintek Division to determine drying rates and corresponding mold growth on building materials such as oriented strand board (OSB), plywood, fiberboard, gypsum board, fiberglass insulation material, ceiling tile and several Canadian wood species lumber, under different environmental conditions. The results showed that, without ventilation, the sample moisture loss was slow and mold growth was found on test materials that were dried at 72% RH or higher, after 4 days. With ventilation, the drying rates of the various materials were much faster than without ventilation, and were not significantly affected by increasing the temperature from 20°C to 25°C. No mold growth was found on most materials that were dried with ventilation at 64% RH or less.

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