Termite guide
Termites do their damage out of sight, and the species determines the treatment. This guide explains the warning signs, how subterranean and drywood infestations differ, which treatment methods fit which situations, and what ongoing protection involves.
The causes
Most foundation damage traces back to one of four sources. Identifying the cause determines which repair approach applies and whether other work, like drainage correction, needs to happen first.
Subterranean termites live in soil and follow moisture to wood. Wood-to-ground contact, mulch against siding, leaky hose bibs, and damp crawl spaces all invite foraging colonies.
Drywood termites fly to exposed wood and bore in, needing no soil contact. Attics, fascia, window frames, and furniture are typical entry points in warm coastal regions.
Termite pressure is geographic: the Southeast, Gulf Coast, California, and Hawaii face year-round activity, while northern states see mostly subterranean species with shorter seasons.
Liquid soil barriers degrade over 5 to 10 years and bait stations stop working when service lapses. Homes that were once protected drift back to vulnerable without anyone noticing.
Urgency
Foundation problems exist on a spectrum. Most homeowners either underreact to serious movement or overreact to cosmetic cracks. Here is how to read the difference.
No activity found, but you live with regional pressure. Annual inspections and moisture control are the cheap layer of defense.
Evidence of activity without visible structural damage. Treating now stops colonies before the damage bill starts compounding.
Active, spreading, or structural-level activity. Termite damage accelerates quietly, and repairs cost far more than any treatment.
Identify your problem
Choose the closest match. The goal is to figure out what information to collect before pricing or calling a pest control company.
Pencil-width earthen tubes climbing foundation walls, piers, or crawl space surfaces.
The signature of subterranean termites, which need soil contact. Liquid soil treatment or bait systems are the standard answers, priced by your home's perimeter.Winged insects emerging indoors, or piles of identical shed wings on sills and floors, often in spring.
A swarm indoors usually means an established colony. Species identification matters here, because subterranean and drywood swarmers lead to different treatments.Wood that sounds hollow when tapped, blistered paint over galleries, or trim that crumbles at a touch.
Visible damage means activity has been underway for a while. Get the infestation scoped and treated first; structural repair is a separate project after activity stops.Small piles of hard, six-sided pellets that look like coarse sand or coffee grounds below kick-out holes in wood.
The signature of drywood termites, which live inside the wood itself. Localized infestations get spot treatment; widespread ones lead to tenting and fumigation.A purchase, sale, or refinance requires a wood-destroying insect inspection or clearance letter.
Inspection plus any required treatment on a deadline. Get the inspection early in the transaction so treatment does not compress against closing.No known activity, but neighbors have treated, or you are in a high-pressure region and want protection.
Preventive soil treatment or a bait system with an annual plan. Prevention pricing runs below active-infestation treatment and locks in monitoring.What gets fixed
Foundation repair is not one thing. The right method depends on what is causing the problem and how far it has progressed. Each approach has a different scope, cost range, and set of exclusions.
Trenching and treating the soil around the foundation to create a continuous barrier that kills and repels subterranean termites. The most common professional treatment.
Runs $3 to $20 per linear foot of perimeter, with most complete treatments between $500 and $1,500.Pricing detail in the cost guideIn-ground stations around the perimeter that foraging termites carry back to the colony. Slower than liquid but less invasive, and doubles as ongoing monitoring.
Runs $8 to $12 per linear foot installed, plus ongoing service to keep stations active.Pricing detail in the cost guideTargeted treatment of a confirmed, contained infestation: localized drywood galleries, a single wall section, or limited subterranean entry.
The budget path when an inspection confirms the activity is genuinely localized, starting around a few hundred dollars.Pricing detail in the cost guideWhole-structure gas fumigation under a tent, the definitive answer for widespread drywood infestations. Requires vacating the home for several days.
Runs $1 to $4 per square foot, or $2,000 to $8,000 for an average home.Pricing detail in the cost guideYearly inspection plus warranty or bond coverage, often with bait station service. Keeps protection current and transfers credibly at home sale.
A recurring annual cost that is small next to retreatment or repair, with terms that vary widely by company.Pricing detail in the cost guideNext steps
Use the resource that matches where you are in the process.