What are the signs of termites in a house?

The clearest signs of termites in a house are winged termites or piles of their shed wings indoors, mud tubes about as wide as a pencil climbing a foundation or framing, and wood that is hollow inside with soil packed into the tunnels. Most people do not know they have termites until they see a swarm or come across damage during construction,^[4] so knowing where to look matters.

Swarmers and shed wings

Swarmers are the winged termites a colony sends out to start new colonies.^[1] Swarming is triggered by warmer temperatures and rainfall, which is why infestations are often discovered in spring.^[1] Winged termites emerging indoors almost always mean an infestation that needs treatment.^[1]

Swarmers are drawn to light, so look around windows, doors, light fixtures and vents.^[3][1] They shed their wings soon after flying. Large numbers of shed wings on windowsills, on floors or caught in spider webs are a sure sign of an infestation.^[3] The swarmers themselves cannot damage wood and live only about a day,^[1] so a broom or vacuum deals with them. The colony that produced them is the real problem.

Where they come out matters. A swarm coming out of a stump or woodpile in the yard does not by itself mean the house is infested, but swarmers emerging next to the foundation or from a porch or patio against the house are a good sign the house is infested too.^[1]

Termite or flying ant?

Termites have wings of roughly equal length, straight antennae and a thick waist.^[4][1] Ants have front wings longer than the hind wings, antennae bent at a sharp elbow and a pinched waist.^[4][1] Ants often swarm at the same time of year as termites,^[1] so it is worth a close look. Keeping a few insects or wings in a sealed bag or jar gives an inspector something to identify.

Mud tubes

Subterranean termites build mud tubes to travel between their colony in the soil and the wood they eat without being exposed.^[1] They are flattened, muddy-looking and most are about the width of a pencil.^[3][1] Look for them on foundation walls, support piers, sill plates and floor joists,^[1] especially in a crawl space or unfinished basement. They are easy to miss when they run along cracks, under flooring, or behind siding and baseboards.^[3]

An inspector may break a tube open to look for small, creamy-white worker termites.^[1] An empty tube does not prove the termites are gone, because they often abandon sections while feeding elsewhere in the house.^[1]

Damaged wood

Termite-damaged wood is hollowed out along the grain, with bits of dried mud or soil lining the tunnels.^[1] Wood damaged by moisture or by carpenter ants does not look like that.^[1] The outer surface usually stays intact, so damage can go unnoticed even in exposed wood.^[1][3]

Clues that the damage is behind a surface:

• Dark areas or blisters in wood floors. Virginia Cooperative Extension lists dark areas or blisters in wood flooring among the common indications.^[3]
• Wood that sounds hollow. Inspectors find tunnels by tapping wood every few inches with the handle of a screwdriver^[3] or probing it for hollow spots.^[4]
• Tiny holes in drywall or plaster with bits of soil around the edges.^[1]
• Rippled or sunken traces behind wall coverings.^[1]

Where to look in a Virginia house

Virginia Tech's extension entomologists single out one common Virginia problem: termites getting in between the foundation and brick veneer, stucco or EIFS that extends below grade. In those houses there is no outside evidence until the damage becomes obvious.^[3] Decks and porches with wood in direct contact with the ground invite termites in too.^[3]

Around the outside, check where soil, mulch or plants are piled against the house. Siding should be at least 6 inches above the soil line;^[5] where it is lower, mud tubes can run up behind it unseen. Around doors and windows, decay in window trim can also point to termites.^[5] Inside, look at crawl space piers, sills and joists, baseboards on outside walls, and around plumbing that comes up through a slab.

Why you might see nothing

Infestations can go undetected for years behind walls, floor coverings and insulation, and even experienced inspectors can miss signs that are hidden.^[1] A clean look around the house is reassuring but not proof. If you are buying a house, have had termites before, or have conditions that attract them, a professional inspection is the honest check. See how to make a house less attractive to termites for the conditions inspectors flag.

What to do once you find a sign

Do not rush into a contract. Termites damage wood slowly,^[1] so taking a few days to compare companies costs little. Leave mud tubes and damaged wood where they are so the inspector can see them, and hold off on store-bought products, which will seldom eradicate an existing termite problem.^[1] Pest control companies often offer free termite inspections,^[2] and getting inspections from more than one company helps confirm whether termites are really there.^[1] For what happens next, read how termite treatments work.

When to call a licensed pro

Any confirmed or suspected termite activity is work for a licensed company. In Virginia, "No person may apply or recommend for use any pesticide commercially without a pesticide business license and the employment of a certified commercial applicator" responsible for safe application.^[6] Applicators who treat for termites are certified in the wood-destroying pest control subcategory,^[7] and VDACS publishes downloadable lists of licensed pesticide businesses and certified applicators^[8] so you can check a company before it starts. Call one when:

• Winged termites or shed wings appear indoors.
• You find mud tubes anywhere on the house.
• Wood sounds hollow, crumbles, or shows tunnels lined with soil.
• You are buying or selling a house.

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