9 Signs of Termite Infestation: What to Look for Before It's Too Late

Why Termites Are Hard to Detect Until Damage Is Significant

Subterranean termites — the most destructive species in the US — work from the inside out. They enter wood through concealed soil pathways, consume the interior cellulose while leaving the outer surface intact, and produce no external noise, no visible insects, and no obvious debris. By the time most homeowners discover an infestation, the colony has been active for one to three years and has consumed meaningful structural material.

Drywood termites, active in coastal and southwestern regions, work more slowly but are equally concealed — nesting entirely within the wood they consume, dropping fecal pellets called frass as the only visible sign. Neither species resembles the pest problem most homeowners expect. Knowing what to actually look for is the first step toward earlier detection.

9 Warning Signs That Warrant a Professional Inspection

These indicators range from definitive evidence of active infestation to conducive conditions that significantly increase infestation probability. Any single sign from the first four items on this list warrants an immediate professional inspection.

• Mud tubes on foundation walls or piers — pencil-width tunnels of soil and termite saliva connecting the soil to wood; active subterranean termite highways
• Hollow-sounding wood when tapped — termites consume wood from the interior, leaving a paper-thin shell that produces a hollow resonance under knuckle pressure
• Soft spots or spongy areas in flooring — flooring that compresses underfoot near walls or in corners may indicate subterranean damage to the subfloor or joists below
• Swarmer wings near windowsills or doorframes — discarded wings from reproductive termites after a swarm flight; their presence inside a structure indicates an established nearby colony
• Frass (termite droppings) — tiny hexagonal pellets resembling sawdust or coffee grounds, found near baseboards or below wood trim; a drywood termite indicator
• Tight-fitting doors or windows — as termites damage structural wood and allow moisture infiltration, frames warp and doors stop closing cleanly; often mistaken for seasonal swelling
• Visible tunnels in exposed wood — galleries carved along the grain of structural members, visible when damaged wood is broken open during renovations or repairs
• Bubbling or peeling paint on wood surfaces — moisture from termite activity behind walls creates pressure that bubbles exterior paint coatings
• Discolored or drooping drywall — drywall that has absorbed moisture from termite-damaged wall framing begins to discolor and lose structural integrity

Where to Look: High-Risk Areas in Every Home

Termite activity concentrates in areas where wood is near soil moisture. The crawlspace is the highest-risk area in any home with below-grade access — sill plates, floor joists, and pier posts in contact with or near grade are first-contact points. Foundation walls where grade soil touches the concrete are consistently where mud tubes first appear.

Interior inspection priorities include the garage framing along the shared house wall, wood trim at exterior door thresholds, and any structural members near plumbing penetrations where moisture concentrations occur. In the attic, drywood termites produce pellet frass that accumulates near structural members — inspect above insulation in coastal and southwestern homes.

Exterior wood features — attached fence sections, deck ledger boards, porch posts resting on concrete, and firewood stored against the foundation — are frequent infestation entry points that then extend into the main structure. Any wood-to-soil contact on the property's exterior is an access risk that should be addressed regardless of current inspection findings.

Termite Damage vs. Carpenter Ant Damage: How to Tell the Difference

The two most commonly confused wood-destroying insects are termites and carpenter ants — and the distinction matters because they require different treatment approaches. Termite-damaged wood has a smooth, carved appearance inside galleries, with walls that follow the grain and are often coated with soil or fecal material. Carpenter ant-damaged wood is clean and smooth — their galleries look almost sandpapered, because carpenter ants remove all debris from the excavation.

Termite frass is small, hexagonal, and sand-grain sized. Carpenter ant frass is coarser — a mixture of wood fragments, soil, and insect body parts that looks like coarse sawdust. Finding fresh frass near a wood surface narrows the species identification significantly.

Flying ants and termite swarmers are also frequently confused at swarm time. The key visual distinction: termite swarmers have two pairs of equal-length wings and a straight, uniform body. Flying ants have unequal wing sizes, a pinched waist, and elbowed antennae. If you capture a sample of the swarmers and are unsure, a professional identification call the day you observe the swarm prevents a misidentification that costs both money and structural protection.