Pest Control for New Homes: What to Do Before the Slab and After You Move In

I've framed over 200 houses and I still see builders skip pre-construction termite treatment to save a couple grand. Then the homeowner calls three years later with subterranean termites in the garage wall. That's a $4,000 problem that could've been a $1,500 line item on the build sheet.

Pre-Construction Termite Treatment

This is the single cheapest termite protection you'll ever buy. A licensed pest control company applies termiticide to the soil before the foundation is poured. For a slab-on-grade home, the treatment goes directly onto the graded soil. For crawl spaces, it goes onto the soil beneath the structure and around foundation footings.

Cost runs $1 to $2 per square foot. A 1,500 square foot slab costs $1,500 to $3,000. That sounds like money until you compare it to a post-construction treatment, which runs $3,000 to $5,000 because they have to drill through finished concrete to inject the product underneath.

The products matter. Termidor (fipronil) lasts the longest in soil -- independent studies show 10+ years of effective barrier. Altriset and Premise (imidacloprid) are solid alternatives that run 5-7 years. Whatever the applicator uses, get the treatment certificate. It lists the product applied, the date, the coverage area, and the warranty terms. You'll need this at resale and for any termite warranty claims.

In many Southern and Gulf Coast states, pre-construction termite treatment is required by building code. Check with your local building department. Even where it's not mandated, FHA and VA loans often require it for new construction financing.

Why Brand-New Homes Still Get Pests

New homeowners assume a new house means no bugs. Wrong. Construction creates pest conditions that don't exist in established neighborhoods. You just bulldozed ant colonies, displaced rodent burrows, and disturbed soil that termites were already living in. All those animals are looking for a new home and yours has fresh wood, open gaps, and no competition.

Construction debris left inside walls and under slabs attracts pests. Wood scraps, foam offcuts, spilled food from work crews, cardboard packaging. I've pulled walls open on punch list items and found sandwich wrappers and soda cans framed right into the cavity. Mice love that stuff.

Fresh lumber is a draw for carpenter ants, especially if any of it got rained on during framing. Wet wood emits the exact moisture signature carpenter ants follow when scouting for nesting sites. Landscaping mulch installed right against the foundation brings ant colonies and termites within inches of your sill plate.

First-Year Pest Timeline

Here's what to expect and roughly when, based on what I've seen across builds in the Southeast and Mid-Atlantic:

Months 1-3: Ants. Lots of ants. Colonies displaced by grading and excavation send scouts in through every tiny gap in the foundation. Pavement ants, odorous house ants, and Argentine ants are the most common invaders. This usually tapers off as colonies re-establish away from the structure.

Months 3-6: Spiders. They follow the ants indoors because that's their food source. Cobweb spiders in corners, wolf spiders in garages. Not dangerous but annoying.

Months 6-12: Mice. Once temperatures drop, mice find gaps that haven't settled or sealed yet. New construction shifts and settles during the first year, and gaps open up around pipe penetrations, HVAC chases, and where siding meets the foundation. A mouse needs a gap the size of a dime.

Hold Off on Quarterly Service

Most pest control companies want to sell you a quarterly plan the minute you close on the house. My advice: wait six months. Let the house settle. Let the initial ant surge pass. Seal the gaps that appear as the framing dries and the foundation cures.

During those first six months, do your own exclusion work. Walk the exterior with a tube of Dow 788 silicone sealant ($8 at any hardware store) and seal every gap around pipes, wires, hose bibs, and vent penetrations. Install door sweeps on the garage service door. Make sure weep holes in brick veneer have copper mesh stuffed in them (keeps mice out, still lets moisture drain).

At the six-month mark, if you're still seeing regular pest activity inside, start a quarterly service. If the exclusion work handled it, save your money and reassess at the one-year mark.

Builder's Punch List for Pest Prevention

These are things I check on every house I build. Most cost nothing if caught during construction:

Keep mulch and landscaping soil at least 6 inches below the sill plate and 12 inches from siding
Grade soil to slope away from the foundation -- standing water against the house invites every pest imaginable
Seal all penetrations through the sill plate and rim joist with fire-block foam
Install hardware cloth (1/4-inch mesh) over crawl space vents
Remove all construction debris from wall cavities before drywall goes up
Store lumber off the ground on pallets during framing, and never leave scrap wood in the yard after the build

Get the pre-treatment done. Clean up your job site. Seal your penetrations. That handles 90% of new construction pest problems before the buyers ever move in.