Mold can occur naturally on lumber under certain conditions, normally due to the presence of moisture in or on the wood, and warm temperatures. Molds are fungi: ubiquitous organisms that (under proper conditions) can grow on organic matter. Surface molds, which can come from a variety of sources including airborne spores, feed off the sugars and starches readily available in wood.
Moisture and Conditions for Wood Decay
Download Lumber Tip Sheet: Managing Moisture and Mold
Download research findings on moisture management: Insulating Raised Floors in Hot, Humid Climates

Mold can occur naturally on lumber under certain conditions, normally due to the presence of moisture in or on the wood, and warm temperatures. Molds are fungi: ubiquitous organisms that (under proper conditions) can grow on organic matter. Surface molds, which can come from a variety of sources including airborne spores, feed off the sugars and starches readily available in wood.
Moisture and Conditions for Wood Decay
Download Lumber Tip Sheet: Managing Moisture and Mold
Download research findings on moisture management: Insulating Raised Floors in Hot, Humid Climates