Two grades of MDF with different levels of moisture resistance are available. Moisture resistant MDF, manufactured by several companies, is intended mainly for interior applications where exposure to high relative humidities or occasional wetting is likely, for example in bathrooms and washrooms. It can be used for non structural applications outside, in sheltered positions, subject to finishing all surfaces and edges with a proven exterior durability system.

Exterior grade MDF, with more limited availability at present, has a substantially higher level of moisture resistance and can be used for a wider range of non structural applications outside with fewer limitations on exposure conditions, but still subject to the need to finish all surfaces and edges with a proven exterior durability system.