Should I hire a pest control company or a waterproofing company for a wet crawl space?

Hire for the cause of the water, not the label on the truck. If liquid water comes in from outside, puddles after storms or seepage at the walls, you need drainage or waterproofing work. If the problem is damp air, bare soil, musty smells or insect damage, many pest control companies handle moisture control, and only a licensed pesticide business can treat termites or carpenter ants. Some crawl spaces need both.

First, find out what kind of wet it is

Look in the crawl space within a day of a heavy rain. What you see sorts the job.

• Standing or running water. Typically, standing water indicates a leaking pipe from above or groundwater entering the space from outside the building or under the floor.^[1] A plumbing leak needs a plumber. Water from outside needs drainage first: gutters, downspouts and grading, then perimeter drains or a sump if that is not enough. The Department of Energy's crawl space guide notes that foundation waterproofing and a perimeter drain strategy on the exterior walls will be required on exceptionally problematic sites,^[1] those with high groundwater or water that cannot be diverted any other way. That is waterproofing company work.
• Damp air, sweating pipes, musty smell, no puddles. This is humidity from bare soil and outside air. A ground cover, sealing and a dehumidifier are the usual fix, and both waterproofing firms and many pest control companies install them. See why a crawl space gets wet to narrow the source.
• Insect signs. Termites and carpenter ants are known to thrive in dark, damp places that have a readily available food source nearby.^[1] Any observed signs will then require a more in-depth inspection and treatment by a pest control professional.^[1] Carpenter ants in particular point to water: Carpenter ants do not damage sound wood. Instead, they make their galleries in water-damaged wood that is soft or rotten.^[9]

What each licence covers in Virginia

Pest control. Under Va. Code § 3.2-3924, No person may apply or recommend for use any pesticide commercially without a pesticide business license and the employment of a certified commercial applicator.^[3] The Virginia Department of Agriculture and Consumer Services says that licence is separate from and in addition to any other commercial business license,^[4] requires insurance of a minimum of $100,000 for property damage, $100,000 for personal injury to or death of one person, and $300,000 per occurrence,^[4] and that All pesticide business licenses expire on March 31 of each year.^[4]

Moisture and waterproofing work. Installing drains, liners, vent seals or a dehumidifier is improvement work on the house, which falls under a different licence. Virginia's contractor law licenses businesses for that work by job size; the Class C licence covers single jobs over $1,000 but less than $30,000,^[5] and the law's definition of improvement says "improvement" shall include (i) remediation, cleanup, or containment of premises to remove contaminants.^[5] DPOR's consumer guide gives a reason to insist on it: By hiring a licensed contractor, you become eligible to receive monetary compensation from the Contractor Transaction Recovery Fund in case of improper or dishonest conduct.^[6]

So a pest control company quoting a vapor barrier job worth more than $1,000 should show you a DPOR contractor licence as well as its pesticide licence. Check the first on DPOR's License Lookup^[7]; see how to check if a contractor is licensed in Virginia.

Mold. If the quote includes mold removal, the Virginia Department of Health notes that the state's Consumer Protection Act requires mold remediation contractors be certified by a nationally or internationally recognized certifying body for mold remediation.^[8]

When you need both

A crawl space with seepage and termite activity needs the insects treated and the water stopped. Sequence it so neither job undoes the other:

• Get the pest inspection first, so moisture work does not cover up activity.
• If the space is being sealed, the installer should leave a minimum 3” termite inspection gap between the top of the wall vapor retarder and the top of the masonry wall,^[2] so the foundation can still be inspected.
• Coordinate with your pest management professional to ensure that the closed crawl space system does not interfere with their treatment or affect their warranty.^[2] Ask both companies this question in writing.

Questions to ask either kind of company

• What is the source of the water, and how did you find it?
• Will your plan stop liquid water, lower humidity, or both?
• What licences do you hold, and in whose name?
• Does the job include a dehumidifier, and who adds an outlet if one is needed?
• Is there a gas furnace or water heater down here, and how does your plan handle its air supply? Sealing vents around such equipment risks potentially creating a deadly situation if naturally ventilated types of combustion equipment are located in the crawlspace.^[1]
• What warranty covers the work, and what voids it?

Stop and call a pro if

• Water stands in the crawl space or runs in at the walls after rain.
• You find mud tubes, swarming insects, sawdust-like piles or wood you can push a screwdriver into.
• Joists or the subfloor sag or feel soft from above.
• Mold covers more than a small patch.
• A gas appliance is in the crawl space and anyone proposes closing the vents.
• There is a smell of sewage, or the sump pump has failed.

For the do-it-yourself side first, see how to lower crawl space humidity. More is under pest control answers, and you can browse crawlspace and moisture services or pest control businesses near Blacksburg.

Describe your wet crawl space once and get quotes from licensed businesses.