Creepy Crawlies in the Crawl Space: Managing Moisture and Pests 

The crawl space tends to be one of those parts of a home that doesn’t get much thought—until there’s a problem. Hidden just beneath your feet, this narrow, often damp area can easily become a magnet for pests. Rodents, insects, and other critters don’t need much of an invitation to move in. A little moisture, a bit of warmth, and they’ll set up shop faster than you’d think. And once they’re in, getting them out can turn into a headache no homeowner wants to deal with.

But with the right approach, you can make your crawl space a whole lot less appealing to unwanted guests. It's less about turning it into a sealed fortress and more about tipping the conditions in your favor—making it a place pests simply don’t want to hang out in the first place.

Why Crawl Spaces Attract Pests In The First Place

To understand how to keep pests out, it helps to first understand what’s drawing them in. Crawl spaces naturally tend to be cool, dark, and humid. For insects like termites, cockroaches, and ants, that’s pretty much a paradise. Rodents love them, too—plenty of quiet corners to nest in, and if they’re lucky, they might even find a forgotten snack or access to a pantry above.

Poor ventilation is a big contributor. When air doesn’t circulate well, humidity builds up. That excess moisture then softens wood, encourages mold, and creates the perfect environment for pests to thrive. Add in any cracks in the foundation, gaps in vents, or openings around pipes, and you’ve got a red carpet rolled out for intruders.

Sometimes insulation gets overlooked, too. Torn or loose insulation not only traps moisture but can serve as nesting material for animals. And if plumbing lines are running through the crawl space, even minor leaks can keep the air damp enough to make conditions even more pest-friendly.

Controlling Moisture Is Half The Battle

The quickest way to ruin a pest’s day is to cut off their water source. Moisture control is arguably the most important step when it comes to crawl space pest prevention. It’s not just about keeping things dry—it’s about managing the conditions in a way that discourages pest activity altogether.

A good starting point is taking a hard look at drainage around the outside of your home. If gutters are clogged or downspouts dump water right next to the foundation, you’ll end up with water seeping under your house. Grading around the home should slope away to direct runoff elsewhere. It’s a small adjustment that can make a massive difference.

Inside the crawl space, installing a vapor barrier can help keep moisture from rising up out of the soil. These heavy-duty plastic sheets are laid across the ground and sealed at the edges to block dampness. For homes in particularly humid regions, adding a dehumidifier can help keep things dry year-round. And if there are any signs of plumbing leaks, even small ones, it’s best to get them fixed before they become a bigger problem.

Once moisture is under control, you’re already a few steps ahead. Without that damp environment, pests lose a big part of what makes the space attractive to them in the first place.

Sealing Entry Points And Reinforcing Defenses

Moisture might be what lures pests in, but access is what makes it possible. Rodents don’t need much of an opening to squeeze through—a hole the size of a quarter is enough for a rat to make its way inside. Insects, of course, can get through even smaller gaps. That’s why inspecting and sealing potential entry points is so important.

Vents should be properly screened, and the mesh needs to be intact with no tears or rust. Foundation cracks, no matter how narrow, are worth addressing. Expanding foam, concrete patch, or professional-grade sealants can work well depending on the surface. Around utility lines—pipes, cables, HVAC ducts—use materials that are tough enough to discourage chewing or tampering.

Access doors to the crawl space should close tightly and ideally have some form of weather stripping to help create a better seal. Any gaps in wooden framing can be filled or reinforced with wire mesh to help block off entry without compromising ventilation.

Insulation should be secure, dry, and free from damage. If you find signs of nesting or shredded material, that’s a strong indicator that something’s already made its way inside. Damaged insulation should be removed, and it's worth considering pest-resistant alternatives when replacing it.

Maintenance That Makes A Long-Term Difference

Preventing a pest problem isn’t a one-and-done kind of job. Like anything around the house, your crawl space needs regular check-ins. Seasonal inspections go a long way, especially after heavy rain or a cold snap—both of which can lead to moisture buildup or new cracks.

Keep an eye out for signs of activity: droppings, gnaw marks, trails in dust, or shredded insulation. Even if you don’t see the pests themselves, these subtle signs are their calling cards. Musty smells or visible mold could point to unresolved moisture issues, which means it might be time to reassess your drainage or ventilation systems.

Sometimes, the best way to stay ahead of a problem is by bringing in professionals who know exactly what to look for. A trained eye can catch things most people might overlook, from minor ventilation issues to barely-visible points of entry that could cause major issues down the road.

In some cases, a more comprehensive solution like encapsulation might be worth considering. This involves sealing the entire crawl space—including walls, floors, and vents—with a heavy-duty liner. While it’s a more involved project, it can be extremely effective in regulating moisture and keeping pests out long-term.

Don’t Wait For A Problem To Act

A clean, dry crawl space might not be something you think about every day, but it has a big impact on your home’s health. It's the foundation beneath the foundation—literally—and if pests take hold there, they’re only a short distance from every other part of your home.

At Splat Pest Control, we help homeowners protect that space before trouble starts. Whether you're seeing signs of critters or just want to make sure your crawl space is properly sealed and dry, we're here to help. From inspections to moisture control and long-term pest deterrents, our team has the tools and experience to keep unwanted guests from getting comfortable.

Contact us today, and let’s talk about how to keep your crawl space pest-free for good. We’ll walk you through your options, answer any questions you have, and recommend a plan that fits your space and your budget. Let Splat Pest Control help you stay one step ahead of invading pests.