Crawl space moisture problems are pest problems, not just building problems
Published Updated
By John Stopka, Co-Founder & CEO · Reviewed by John Stopka
A damp crawl space is a pest problem before it is anything else. Moisture is what makes the space liveable for termites, carpenter ants, damp-wood beetles and the crawling insects that want somewhere cool and wet to sit, which is why treating the insects without dealing with the water only buys time. You cannot treat your way out of a moisture source, so the moisture is the actual job.
Why is a damp crawl space a pest problem?
Because the water is what makes the space habitable.
University of Kentucky entomologists put it plainly for termites: "Termites are attracted to moisture and are more likely to infest if the soil next to the foundation is consistently moist" [1].
It is the same story further down the list. Sowbugs and pillbugs have a "need for moisture" that "may also drive them into crawl spaces, basements, and ground level floors" [2]. Centipedes and millipedes are "associated with damp, moist areas", and damp conditions close to a home "facilitate their occasional entry into the home" [3].
The insects are the symptom. The water is the condition that put them there.
Which pests does crawl space moisture bring?
Three groups, worth keeping separate: they are three problems that share one cause.
Wood-destroying insects. Subterranean termites are the headline; carpenter ants the other. Carpenter ants "tunnel through moist wood, but can also inhabit dry wood", and "leaky pipes, damaged roofing, poorly ventilated attics, and clogged gutters can serve as constant moisture sources that attract the ants to your home" [4].
Insects that need damp wood to develop. Anobiid powderpost beetles are the clearest example. They "prefer to infest moist wood", and "a 13-30% moisture content is required for development of the larvae" [5]. So "infestations are most severe in damp crawl spaces, basements, garages, and unheated outbuildings" [5].
Everything that just wants somewhere cool and damp. Sowbugs, pillbugs, centipedes, millipedes and springtails all end up in the same substructure; springtails are "highly dependent on a consistent water source" [6]. University of Illinois Extension names "a crawl space with open dirt" among the damp spots that produce fungus gnats indoors [7].
Does moisture really attract termites?
Yes, and it is worth being specific. Subterranean termites depend on soil moisture. Kentucky's termite fact sheet notes that termites cut off from the ground "die off as well, since they cannot return to the soil for supplemental moisture" [8].
Two other conditions travel with it. "Termite problems often occur when wood components of the building are in direct contact with soil", and even landscaping counts, because "termites are attracted to mulch primarily because of its moisture-retaining properties" [1].
A crawl space that stays wet supplies the moisture, and often the wood contact too — a conducive condition, not bad luck.
Why can't you just treat the pests?
Because for most of these pests dryness is the control, and a treatment does not make anything dry.
The same point keeps appearing. On powderpost beetles: "Buildings with central heating and cooling seldom have sufficient dampness to support beetle development in living areas or attics" [5]. On sowbugs and pillbugs: "Without high moisture, pillbugs and sowbugs find it almost impossible to survive indoors" [2].
And on what to do about it: for springtails, "controlling dampness in and around the home is the first course of action" [6]; for carpenter ants, "to prevent re-infestations you should eliminate sources of moisture and cracks or crevices" [4].
Different insects, one answer. Treatment handles what is there now; the moisture decides whether it comes back.
Where does crawl space moisture come from?
Usually from how water is handled around and under the building.
University of Kentucky guidance points at soil next to the foundation that stays moist, ground that does not drain away, and water that gutters and downspouts are not carrying clear [1]. Liberty's own Home Services page makes the same link: "Overflowing gutters soak the soil and wood along your foundation, and damp wood and soil draw termites, carpenter ants and other moisture-loving pests."
Underneath, bare soil is its own source, and Kentucky's guidance describes reducing crawl space moisture by covering most of that soil with polyethylene sheeting [1]. Inside, the culprits are duller: leaky pipes, poor air circulation, and the slow leak nobody has found yet [4][7].
How does Liberty handle a damp crawl space?
Two different parts of the company, depending on what the inspection finds.
Pest problems often start with the building — a damp crawlspace, gaps at the roofline, insulation animals have been in. Liberty Home Services handles that side of it: vapor barriers, wood-decay fungus removal, crawlspace doors and vents, insulation and exclusion work.
That side starts with a free inspection. A Service Advisor checks your crawlspace and attic for moisture, wood problems, insulation needs and pests. Then they recommend fixes.
The crawlspace work itself:
- We install a 10-mil white vapor barrier in your crawlspace to help control moisture.
- We remove wood-decay fungus from the floor joists in your crawlspace.
- New doors and vent covers for your crawlspace.
- Clearing out debris from your crawlspace.
Liberty Home Services is available in the Paducah area, Southern Illinois and the Hopkinsville area. It is not available in the Bowling Green area.
The pest side runs in parallel, everywhere Liberty works. A termite inspection is free and anyone can book one; they also look for things that attract termites, like wood touching soil or moisture problems.
The damp-loving insects that come up out of a crawl space — centipedes, crickets, silverfish, spiders and American cockroaches — are covered by every Liberty pest control plan. Termites and carpenter ants are not plan pests.
When to call a professional
Call when the ground under the house stays wet, when a home inspection report flags crawlspace moisture, or when insects keep turning up on the lower floor after treatment.
An inspection sorts out which problem you actually have: whether there are wood-destroying insects in the structure, whether the damp is feeding a beetle or ant population, and whether the fix is a treatment, crawlspace work, or both.
Common questions
Does a damp crawl space attract termites?
Yes. Termites are attracted to moisture and are more likely to infest when the soil next to the foundation stays consistently moist [1]. They also depend on the soil for moisture [8], which is why damp ground under a house matters.
What bugs live in a wet crawl space?
Several groups at once. Damp wood supports anobiid powderpost beetles, worst in damp crawl spaces and basements [5], and carpenter ants tunnel through moist wood [4]. Sowbugs, pillbugs, centipedes, millipedes and springtails are drawn to the damp and move in from there [2][3][6].
Will treating the insects fix the problem?
Not on its own. For most of these pests dryness is the control: sowbugs and pillbugs find it almost impossible to survive indoors without high moisture [2], and buildings without enough dampness seldom support powderpost beetle development [5]. Treatment deals with what is there now; the moisture decides whether it returns.
Do pest control plans cover crawl space pests?
Centipedes, crickets, silverfish, spiders and American cockroaches are covered by every Liberty pest control plan. Termites and carpenter ants are not plan pests. The crawlspace work itself is Liberty Home Services.
Do springtails in the crawl space bite?
No. Springtails do not bite or sting humans or animals [6]. They are a sign of dampness, which is why the advice starts with controlling dampness in and around the home [6].
Sources
- University of Kentucky Entomology. Michael F. Potter. "Protecting your Home Against Termites" (ENTFACT-605). https://entomology.mgcafe.uky.edu/ef605 (opens in a new tab)
- University of Kentucky Entomology. "Sowbugs & Pillbugs" (ENTFACT-439). https://entomology.mgcafe.uky.edu/ef439 (opens in a new tab)
- University of Kentucky Entomology. "Centipedes & Millipedes in & Around the Home" (ENTFACT-645). https://entomology.mgcafe.uky.edu/ef645 (opens in a new tab)
- University of Kentucky Entomology. "Carpenter Ants" (ENTFACT-603). https://entomology.mgcafe.uky.edu/ef603 (opens in a new tab)
- University of Kentucky Entomology. Michael F. Potter. "Powderpost Beetles" (ENTFACT-616). https://entomology.mgcafe.uky.edu/ef616 (opens in a new tab)
- University of Kentucky Entomology. "Springtails" (ENTFACT-420). https://entomology.mgcafe.uky.edu/ef420 (opens in a new tab)
- University of Illinois Extension. Richard Hentschel. "Take care of nuisance pests around the house." January 24, 2022. https://extension.illinois.edu/blogs/over-garden-fence/2022-01-24-take-care-nuisance-pests-around-house (opens in a new tab)
- University of Kentucky Entomology. Michael F. Potter. "Termite Control: Answers for Homeowners" (ENTFACT-604). https://entomology.mgcafe.uky.edu/ef604 (opens in a new tab)