Mold in a Crawl Space

Most molds found in crawl spaces are commonly called mildew and are plant-like organisms that grow along surfaces and that require food and moisture. Wood surfaces, paper, leather, cardboard, and even the dust trapped in fibrous insulation can support mold growth. It’s impossible to remove all foods for mold from an environment, but you can minimize moisture, which will prevent mold growth.

Breathing in living or dead mold spores can cause health symptoms, so you don’t want mold to remain in spaces where you live or work. You don’t live or work in your crawl space, but air from the space may rise up into the rooms above – and that air can contain mold spores.

With very few exceptions, mold does not degrade wood. Where wood has been dripping wet for weeks, however, wood-decaying fungi may be growing in the crawl space. If you see rotten or soft wood or even mushrooms, a contractor should evaluate the wood, as structural repairs may be needed.

Where Might The Mold Be Growing in a Crawl Space?

Mold grows on stored goods, on surfaces of floor joists, subflooring and beams, on debris and even dust on a dirt floor, and on the invisible dust trapped in exposed fiberglass insulation or crushed stone. Even if there’s a vapor barrier over the soil, mold can grow on the dust settled on top of the barrier. Any of this mold growth can cause the musty odors associated with crawl spaces.

Why Is the Mold Growing There?

Crawl spaces get moldy because there’s too much moisture present. Water can come from the exterior because of poor drainage and grading or humid exterior air may be flowing into the crawl space through vents. Moisture can also come from the crawl space itself, due to the presence of an uncovered dirt floor or a pipe leak.