Termites cause over $5 billion in damage to American homes every year, and most homeowners insurance policies won’t cover a cent of it. If you live in a wooden house or any home with wood framing, understanding how termites operate, what to look for, and how to protect your property can save you thousands of dollars in structural repairs.
Types of Termites That Target Homes
Two main types of termites attack wooden structures, and they work in very different ways.
Subterranean termites are the more destructive of the two. They build large underground colonies and travel up into your home through pencil-width mud tubes that run along foundation walls, support piers, and plumbing. They need constant moisture to survive, which is why they maintain that connection to the soil. When they feed, they eat along the wood grain and leave mud or soil inside their tunnels. Problems from subterranean termites typically don’t show up until at least 10 years after a home is built, but once established, these colonies can persist for decades.
Drywood termites skip the soil entirely. They fly directly to exposed wood, burrow in, and build their entire colony inside the timber itself. These colonies are smaller, but they’re harder to detect because there’s no mud tube trail leading back to the ground. Drywood termites eat across the wood grain, creating hidden galleries that weaken structures from the inside. The clearest sign of their presence is tiny, six-sided fecal pellets (called frass) that they push out of small “kick-out holes,” leaving small piles that look like coarse sawdust on floors or countertops.
Signs of an Active Infestation
Termite damage is slow and cumulative. It builds over years, not days, which means the signs can be subtle long before they become obvious. Many homes sustain more than $7,500 in damage before the infestation is even discovered. Here’s what to watch for:
- Mud tubes on foundation walls. These narrow, dirt-colored tubes run along exterior and interior foundation surfaces, support piers, and plumbing lines. They protect subterranean termites from open air and predators.
- Pinholes in walls or ceilings. Small, BB-sized spots of dried mud on sheetrock or paneling appear when termites accidentally break through a surface and patch it from the inside.
- Sunken lines under paint or wallpaper. Narrow, winding trails or depressed areas beneath wall surfaces indicate termites feeding on the paper backing of sheetrock.
- Swarmers indoors. Winged termites emerging from walls, ceilings, or floors, or piles of shed wings near windowsills, mean a mature colony is living inside the structure.
- Pellet piles. Small accumulations of uniform, grain-like pellets on floors or countertops signal drywood termites above.
- Structural sagging. A floor that feels spongy, a door frame that crumbles when touched, or a roof line that dips can all point to years of hidden termite feeding. If damaged timbers contain galleries lined with dried dirt, that’s termite damage.
How Much Damage Can They Do?
Termite damage isn’t sudden or catastrophic. It accumulates quietly. A colony won’t collapse your house in a season, but given enough time, the structural consequences are serious and expensive. Replacing damaged structural beams runs $2,000 to $10,000. Floor and ceiling repairs cost $1,500 to $7,000. Foundation damage, the worst-case scenario, can reach $25,000.
Because most standard homeowners insurance policies classify termite damage as preventable through maintenance, you’ll likely be paying for all of it out of pocket. That’s why detection and prevention matter far more than treatment after the fact.
Treatment Options and How They Work
The average termite treatment costs between $1,000 and $3,000 depending on the severity and method used. For subterranean termites, there are two main approaches, and they work differently than most homeowners assume.
Liquid soil treatments involve applying a chemical barrier around your home’s foundation. A 2024 University of Florida study found that these treatments effectively prevent damage to the structure itself, but they only kill about 1.5% of the actual colony living in the surrounding soil. What happens is that termites die near the treated zone, creating a “death zone” that extends roughly 8 feet from the treatment area. The smell of dead termites causes the rest of the colony to avoid that area. So the treatment works as a barrier, but the colony survives underground and can eventually find other paths to your home or neighboring structures.
Bait stations take a different approach. Placed in the ground around your property, they attract foraging termites that carry slow-acting toxins back to the colony. Over time, this can actually eliminate the colony entirely, with far less chemical application than liquid treatments. One important detail: bait stations shouldn’t be placed too close to an existing liquid treatment, because the “death zone” from the liquid barrier may prevent termites from ever reaching the bait.
For drywood termites living inside the wood itself, localized treatments can work for small infestations. But for widespread drywood infestations, whole-house fumigation is often the only effective option. The process involves tenting the entire structure and filling it with a fumigant gas at concentrations between 1,440 and 3,850 parts per million. Everyone, including pets and plants, must leave. All unsealed food, medicine, and items covered in plastic need to be removed or double-bagged in special protective bags. After the tent comes off, the gas dissipates quickly, but you can’t re-enter until measured levels drop below 1 part per million. The whole process typically keeps you out of your home for two to three days.
Preventing Termites in a Wooden House
Moisture is the single biggest factor that draws termites to a structure. Leaky pipes, poor drainage, and inadequate ventilation under the house all create the damp conditions subterranean termites need. Fixing these issues does more to protect your home than almost any other preventive step. Make sure gutters direct water away from the foundation, crawl spaces are ventilated, and there’s no standing water near the house.
Wood-to-soil contact is the other major vulnerability. Anywhere that structural wood, siding, or decorative trim touches the ground gives termites a direct highway into your home without needing to build visible mud tubes. Excessive vegetation growing against the house creates similar hidden pathways and traps moisture against wood surfaces.
Pressure-treated lumber offers real protection for the most vulnerable parts of a structure. Modern ground-contact treated wood uses copper as its primary insect-killing ingredient, paired with fungus-fighting compounds. Lumber that won’t touch the ground uses a different chemistry built around an insecticide that’s effective against termites without the copper. If your home was built before 2003, its treated lumber likely contains an older formulation based on copper, arsenic, and chromium, which was effective but has since been phased out for residential use. Pressure-treated lumber isn’t a whole-house solution, but it’s valuable for decks, porch framing, sill plates, and any wood near grade level.
How Often to Get an Inspection
Pest control professionals recommend a termite inspection at least once a year for any home. In warm, humid climates where termite pressure is highest, more frequent checks may be warranted. Older homes also benefit from closer monitoring, since aging wood, settling foundations, and decades of potential moisture issues all increase risk.
A professional inspection focuses on the areas you’re least likely to check yourself: crawl spaces, foundation walls, the undersides of porches, plumbing penetrations, and anywhere wood contacts or approaches soil. Given that damage often goes undetected for years and insurance won’t bail you out, an annual inspection costing a couple hundred dollars is one of the more straightforward ways to protect what is likely your largest investment.