Termite Damage Repair Guide

Termite damage is distinct from other wood rot. Subterranean termites (the most common type in the US) eat wood from the inside out, leaving a thin outer shell that appears intact. Tap the wood with a screwdriver—if it sounds hollow, termites have consumed the interior. Look for mud tubes on foundation walls, floor joists, and sill plates. These pencil-thin tubes provide protected passage from the soil to the wood. Discard the mud tubes: if they are rebuilt, the infestation is active. Look for swarmers (winged termites) near windows and light fixtures in spring. Frass (termite droppings) resembles small, six-sided pellets. Probe wood members near suspected damage—a screwdriver that sinks in easily confirms structural weakening. Distinguish termite damage from water damage: termite-damaged wood has a layered, paper-like appearance; water-damaged wood is soft and fibrous.

Never repair termite damage without first treating the infestation. A licensed pest control professional will inspect and recommend a treatment plan. Standard treatments: liquid soil barrier (termicide applied around the foundation perimeter creates a chemical barrier that kills termites entering the soil), bait stations (installed around the property—termites feed on the bait and carry it back to the colony), and wood treatment (borate-based sprays applied directly to exposed wood). Treatment costs vary: liquid barrier $500–$1,500 for a typical home, bait stations $800–$2,000 initial installation with $200–$500 annual maintenance. Most treatments include a 1-year warranty with renewal options. Get a clearance letter from the pest control company stating the infestation is treated before starting structural repairs. This protects you from reinfestation and is required for permits.

Three repair methods address termite-damaged wood. Sistering: a new piece of lumber is bolted or nailed alongside the damaged member, sharing the load. This is appropriate when less than 25% of the cross-section is damaged. The damaged portion can remain (the sistered piece carries the load) or be removed. Cutting and replacing: the damaged section is cut out and a new piece is spliced in, supported by metal joist hangers or structural connectors. This is used when a section of a beam or joist is damaged but the rest is sound. Full replacement: the entire damaged member is removed and replaced. This is necessary when more than 25% is damaged or the member is a critical structural element (sill plate, main beam). All new wood should be pressure-treated or naturally termite-resistant (cedar, redwood, or ACQ-treated lumber). Use galvanized or stainless steel fasteners (treated wood corrodes standard fasteners).

After repairing termite damage, implement a prevention plan. The most critical step: eliminate wood-to-soil contact around your home. No wood siding, trim, or framing should touch the ground—maintain a 6-inch minimum gap between soil and wood. Remove wood debris, stumps, and lumber from the yard near the foundation. Fix grading and drainage issues that keep soil moist (termites thrive in moisture). Seal foundation cracks that provide entry points. Maintain the termite treatment barrier with annual inspections. Keep firewood, lumber, and wood debris at least 20 feet from the house and elevated off the ground. Install a termite shield (metal flashing) on top of the foundation wall during new construction or major renovation. Annual professional termite inspections ($75–$150) detect early activity before significant damage occurs.

Termite damage repair costs vary widely. Minor localized repair (sistering one joist): $500–$1,500. Moderate repair (replacing several joists or a sill plate section): $1,500–$4,000. Major repair (structural beam or wall replacement): $5,000–$15,000. Full structural remediation if infestation went unchecked for years: $15,000–$50,000+ for complete floor or wall reconstruction. As noted, standard homeowners insurance does not cover termite damage. However, some companies offer termite damage riders or separate termite protection policies. These typically cost $50–$150/year and cover up to $250,000 in structural damage. In real estate transactions, termite damage requires disclosure in most states. Sellers often pay for treatment and repairs as a condition of sale. The best financial strategy is annual inspection ($75–$150) and prompt treatment at first sign of activity.