The Causes of Crawl Space Mold

Why does crawl space mold happen? There are a few reasons your home might develop mold or mildew in your crawl space. It depends largely on a variety of things that your home may include or that may be happening to your home.

If you’re dealing with a problem like mold on the floor joists in the crawl space, the causes could be varied. These are some of the most common potential problems. 

Open Crawl Space Vents

For a long time, people believed that crawl spaces needed to “breathe.” Because that was the prevailing wisdom, many homes now have open crawl space vents, which many homeowners believe makes the crawl space more healthy.

However, over the years, it’s come to many people’s attention that this isn’t the case. Because crawl space vents introduce external air, which is often high in humidity, into the area, this is a recipe for crawl space moisture.

When you have moisture in your crawl space, that frequently leads to crawl space mold. Open crawl space vents tend to cause this problem. 

Plumbing Issues and Leaks

Of course, another potential problem is much easier to discover. If you’re dealing with enough moisture that you have standing water in your crawl space, it’s likely that you actually have a leak dripping water into the area.

Plumbing problems can cause standing water in your crawl space. That may include flooding that happens in your home that then leaks down into the crawl space as well as plumbing problems that cause water to flow directly into the crawl space.

Regardless of the reason, standing water in your crawl space can introduce even more moisture into the area. That leaves you at a higher risk for mold crawl space problems. 

Flooding Outside and Wet Soil

This is especially a problem if you have a dirt crawl space. It’s more common for mold on the floor joists in your crawl space to form if the area is perpetually wet because it offers a more welcoming environment all the time.

Even if you have a brick or stone foundation, however, the wet soil in the area will expand and push against that foundation, potentially leading to cracks and breaks in the foundation. Almost inevitably, that means you’ll have water leaks.

If your area has recently dealt with flooding or an abnormally rainy season, the soil around your home could be holding more dirt than usual. It’s always a good idea to request an inspection just to be sure in these situations.