Carpenter ant damage vs. termite damage: how to tell the difference?

Clean tunnels and a pile of shavings. Carpenter ants don't eat wood; UC IPM notes they excavate it to make nests, and Penn State describes the galleries as smooth-sided with no soil particles, almost sanded. The excavated wood has to go somewhere, and Penn State notes the particles are sifted out through cracks, which is the pile of coarse sawdust you find on a windowsill, a basement floor or a deck board below the nest. University of Minnesota's extension calls that coarse sawdust the sign of a nearby nest. The frass often has bits of insulation and insect parts mixed in. Carpenter ants prefer wood that's already wet or soft, and Penn State notes they will not infest sound wood with a moisture content under 15 percent, so the damage is usually around a leak, a window, a roof edge or a sill.

Dirt in the wood and mud on the wall. Subterranean termites eat the wood, so there's no sawdust. Penn State describes infested wood as having runways coated with an earth-like material, and when it's extensive, largely hollowed out and rotten in appearance. UC IPM adds that the surface is typically thin and easily punctured with a screwdriver, and may darken or blister. The giveaway outside the wood is the mud tube: an earth-colored runway up a foundation wall, a post or a sill plate that termites build to travel from the soil to the wood. Carpenter ants never build those.

Because the treatments are completely different. Carpenter ant control means finding and treating the nest in the house and the parent colony outside it, usually with baits or a dust in the void, and fixing the moisture. Termite control means a soil treatment or bait program around the foundation. A termite treatment does nothing for carpenter ants and vice versa, and Penn State notes termite warranties specifically exclude carpenter ants. Penn State also notes that carpenter ant structural damage is rarely significant, whereas termites can hollow out framing, which changes how urgent the job is.

We see both, often in the same kind of spot. On the North Shore, in Huntington, Northport and Setauket, carpenter ants in the roof edge, a bay window or a deck ledger are the common find, with sawdust on the sill below. On the South Shore and in the Nassau slab neighborhoods, Levittown, Massapequa, Seaford, termites at the sill plate or coming up through the slab are more common. If you're not sure, send us a photo of the damage and the pile beneath it. Carpenter ant treatment carries a 6-month guarantee and termite treatment 1 to 2 years; both start with a free estimate.