Signs of Termites: How to Spot an Infestation Early

What termite signs usually mean

Termites eat cellulose — the material in wood, cardboard, and paper — and they prefer to work hidden, inside walls, under floors, and in soil against your foundation. Because you rarely see the insects themselves, you are almost always spotting the evidence they leave behind rather than the colony. The two most important things to understand: most damage happens out of sight, and a single clear sign (like a mud tube or a pile of wings) usually means an active or recent colony, not a stray bug.

There are three common types in U.S. homes — subterranean (the most widespread and most destructive, nesting in soil), drywood (living inside the wood itself, common in warm coastal regions), and dampwood (drawn to wet, decaying wood). The signs overlap, but where you find them helps narrow things down.

The most common signs, most to least obvious

Ordered roughly from the clearest evidence to the subtlest, here is what to look for:

• Mud tubes — pencil-width tunnels of dried mud running up your foundation, crawl-space piers, or basement walls. Subterranean termites build these to travel between soil and wood. Active tubes are the single most reliable sign.
• Discarded wings — small piles of identical translucent wings near windowsills, door frames, or spider webs. After termites swarm to start new colonies, they shed their wings. Wings that are all the same size point to termites (ants shed uneven wings).
• A swarm of winged insects — indoors, especially in spring, a cluster of flying insects near a light or window is often reproductive termites. Termites have straight antennae, equal-length wings, and a broad waist; flying ants have a pinched waist and unequal wings.
• Hollow-sounding or soft wood — termites eat wood from the inside out, leaving a thin outer shell. Wood that sounds hollow when tapped, or that a screwdriver sinks into easily, is a strong signal.
• Bubbling, peeling, or uneven paint — moisture and tunneling just under a painted surface can make paint blister or look like water damage where there is no obvious leak.
• Frass (drywood droppings) — tiny, ridged, pellet-shaped droppings that look like sawdust or coffee grounds, often in small mounds beneath infested wood.
• Tight-fitting doors and windows or sagging floors — as termites damage and warp wood, frames stick and floors feel spongy. This is a later-stage sign.

Safe checks you can do yourself

You can gather a lot of useful information without any risk. None of these involve chemicals, structural work, or entering an unsafe crawl space — just careful looking.

1. 1Walk your foundation, inside and out, with a flashlight and look for mud tubes on concrete, brick, and crawl-space piers. Gently break a small section of one — if it is rebuilt within a day or two, the colony is active.
2. 2Tap along baseboards, door frames, window sills, and any exposed structural wood with the handle of a screwdriver, listening for a hollow, papery sound.
3. 3Check windowsills, along interior walls, and inside light fixtures for piles of discarded wings, especially in spring.
4. 4Look for frass — small pellet mounds — under wooden furniture, beams, and trim, and note whether paint anywhere is blistering without a water source.
5. 5Inspect anywhere wood meets soil: deck posts, fence lines touching the house, firewood stacked against the wall, and mulch beds near the foundation.
6. 6Reduce moisture that attracts termites — fix dripping spigots, redirect downspouts away from the foundation, and clear debris from crawl-space vents.

What you should not do: probe deep into structural beams, tear open walls, or apply store-bought pesticides broadly. Poorly targeted treatment can scatter a subterranean colony to new areas of the house and make professional treatment harder.

Danger signs — stop and get help now

A few findings mean the problem is beyond a DIY inspection and needs a licensed professional promptly:

• A visible active swarm inside the house, or fresh wings appearing repeatedly — this signals an established, reproducing colony.
• Sagging or spongy floors, a bouncing subfloor, a sticking door tied to a warped frame, or any wall or ceiling that looks like it is bowing — these can point to structural damage. Treat a genuine structural sag as a safety issue and keep weight and traffic off the area until it is assessed.
• Extensive mud tubes across load-bearing beams, sill plates, or floor joists in a basement or crawl space.
• Termite evidence combined with obvious water damage or rot — the two together accelerate structural weakening.

When to call a professional

Call a licensed pro if you find any active sign — mud tubes, a swarm, wings, frass, or hollow wood — or if you simply cannot rule termites out. Early confirmation is cheap insurance; waiting is what turns a contained problem into structural repair. A good inspection identifies the species, maps the extent, and gives you a clear treatment and, if needed, repair plan.

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