Termites cause an estimated $5 billion in property damage across the United States every year, and most homeowner insurance policies do not cover the repairs. The challenge is that termites work silently behind walls, beneath floors, and inside structural lumber — often for years before anyone notices. Understanding termite damage signs and treatment options gives you the best chance of catching an infestation early, when repairs are manageable and treatment costs are lowest. Here is what to look for and exactly how to respond.
Types of Termites in the United States
Three main termite groups affect US homes, and each leaves different evidence behind. Subterranean termites are the most destructive, accounting for roughly 80% of all termite damage nationwide. They live in underground colonies that can number in the millions and build mud tubes to reach wood above the soil line. Eastern subterranean termites dominate the East Coast and Midwest, while Formosan subterranean termites — an especially aggressive species — are concentrated in the Southeast and Gulf Coast.
Drywood termites infest wood directly without needing soil contact. They are most common in coastal Southern California, Florida, and Hawaii. Dampwood termites target high-moisture wood and rarely infest sound structures, but they can damage decks, fence posts, and leaky crawl spaces in the Pacific Northwest.
Warning Signs of Termite Damage
Catching termites early depends on knowing what to look for during routine home maintenance. Watch for these indicators:
- Mud tubes: Pencil-width tunnels running up foundation walls, piers, or plumbing pipes. Break one open — if live termites are inside, the infestation is active.
- Hollow-sounding wood: Tap baseboards, door frames, and window sills with a screwdriver handle. Damaged wood sounds papery or hollow.
- Frass (drywood termites): Tiny, six-sided pellets the color of sawdust piled near windowsills, door frames, or along baseboards.
- Swarmers: Winged termites emerging indoors, especially in spring. Discarded wings on windowsills are a telltale sign.
- Blistered or bubbling paint: Moisture from termite activity behind drywall causes paint to bubble, peel, or appear water-damaged.
- Sagging floors or ceilings: Advanced infestations compromise structural lumber, causing visible deflection.
How to Inspect Your Home for Termites
Perform a visual inspection twice a year — once in early spring before swarm season and once in fall. Start in the crawl space or basement with a bright flashlight and a flathead screwdriver. Probe the sill plate, rim joist, and any wood in contact with or near the soil. Damaged wood crumbles easily and may reveal live workers — small, pale, soft-bodied insects about 1/4 inch long.
Outside, check foundation walls for mud tubes, inspect the grade around the perimeter for wood-to-soil contact, and examine any landscaping timbers, railroad ties, or mulch beds within 3 feet of the foundation. Professional termite inspections cost $75 to $150 and are worth scheduling every 2 to 3 years, especially in high-risk regions like the Southeast.
Treatment Options for Subterranean Termites
Liquid soil treatments create a chemical barrier around the foundation that kills termites as they forage through the treated zone. Termidor (fipronil) and Taurus SC are the most widely used products, with treatment costs ranging from $1,200 to $3,000 for a typical 2,000-square-foot home. A licensed pest control operator trenches or rod-injects the product along the foundation perimeter and around piers, creating a continuous barrier that lasts 5 to 10 years.
Bait systems such as Sentricon and Trelona offer a less invasive alternative. In-ground stations installed every 10 to 15 feet around the home contain cellulose bait laced with a slow-acting insect growth regulator. Foraging workers share the bait with the colony, eventually eliminating it. Installation runs $1,500 to $3,500 with annual monitoring fees of $250 to $400. Bait systems work well for ongoing prevention but may take 3 to 12 months to eliminate an active colony.
Treatment Options for Drywood Termites
Localized treatments target individual infestations when damage is confined to a small area. A pest control operator drills into the infested wood and injects a termiticide foam or dust — typically a borate or fipronil formulation — directly into the galleries. Spot treatments cost $200 to $600 per area and work best when you can confirm the infestation is limited.
Whole-structure fumigation (tenting) is the only treatment guaranteed to reach every drywood termite colony in a building. The home is sealed under a gas-tight tarp, and sulfuryl fluoride gas is introduced at a precise concentration for 24 to 72 hours. Fumigation costs $1,500 to $5,000 depending on the home’s size, but it provides complete elimination with no residual — meaning termites can re-infest immediately after treatment. Pair fumigation with preventive borate treatments on exposed wood to extend protection.
Repairing Termite-Damaged Wood
Minor cosmetic damage in non-structural trim, casings, and baseboards can be filled with a two-part wood epoxy like Abatron WoodEpox ($25 to $40 per quart). Dig out all soft, damaged material with a chisel, apply a liquid consolidant to harden remaining wood fibers, then fill with epoxy and sand smooth once cured.
Structural damage to sill plates, joists, and studs requires sistering new lumber alongside the compromised member or replacing the damaged section entirely. This is not a DIY job — hire a licensed contractor to evaluate load paths and ensure the repair meets local building code. Structural termite repairs average $1,500 to $8,000 depending on the extent of damage and accessibility.
Preventing Future Infestations
Eliminate wood-to-soil contact wherever possible. Building codes require a minimum 6-inch clearance between the soil surface and any wood framing. Pull mulch, soil, and landscaping back from the foundation so you can see the concrete or block surface during inspections. Fix plumbing leaks, improve drainage, and ensure crawl spaces have adequate ventilation — target at least 1 square foot of vent area per 150 square feet of crawl space.
Store firewood at least 20 feet from the house and never stack it against the siding. Remove dead trees, stumps, and buried construction debris from the yard. When building additions or decks, use pressure-treated lumber rated for ground contact (UC4A or higher) and treat cut ends with a copper naphthenate preservative. These measures do not guarantee you will never see termites, but they make your home a far less attractive target.
How Much Does Termite Treatment Cost
Budget between $500 and $5,000 for termite treatment depending on the method, infestation severity, and your home’s size. Here is a quick cost comparison:
- Liquid barrier treatment: $1,200 to $3,000 (lasts 5 to 10 years)
- Bait system installation: $1,500 to $3,500 plus $250 to $400 per year for monitoring
- Spot treatment (drywood): $200 to $600 per area
- Whole-structure fumigation: $1,500 to $5,000
- Structural repairs: $1,500 to $8,000+
Get at least three quotes from licensed pest control companies. Ask about warranties — most reputable firms offer a 1- to 5-year retreatment guarantee. Early detection and prompt treatment almost always cost less than ignoring the problem and hoping it goes away.
