One of the most common and serious issues we find in crawl spaces is the onset of dry rot. Sill plates, the wooden structure sitting directly upon your foundation, are susceptible to rot due to moisture-wicking upwards from the foundation wall. Floor joists, which sit upon sill plates and support the subflooring above, rot from either excessive water vapor content, a water intrusion above, or wicking from the sill plate below. Rim Joists or band boards are likely to accumulate dry rot because of the surface area they have exposed to the exterior walls. Subflooring, which lays upon floor joists to create a suitable base for flooring, is another common target of rot. Rot in crawl spaces can be quite serious, but ignoring the problem means it’s likely to become even more serious as it spreads to other structural components of your home.
Fungi is not the only organism that thrives in a damp crawl space environment. Mold and other pests can thrive also. Once mold takes hold, air circulated through your crawlspace can spread mold spores throughout the rest of your house. Those strong, musty odors coming from your crawl space could also be a sign of raccoon, rat, or other insect infestations. And if you have standing water in the crawl space, leaking, or high moisture content in the air, that not only leads to fungal growth but can also cause problems with warped flooring, drywall mold, etc.