Those small piles of what looks like sawdust near your walls, windowsills, or furniture are one of the most recognizable signs of a drywood termite infestation. But termites don’t actually produce sawdust. What you’re seeing is frass, which is termite droppings pushed out of tiny holes in infested wood. Knowing what termite frass looks like, where it appears, and how it differs from actual sawdust can help you figure out exactly what’s going on in your home.
What Termite “Sawdust” Actually Is
Termites digest the wood they eat, so what comes out the other end isn’t wood shavings at all. Drywood termites produce hard, dry fecal pellets that are roughly 0.5 to 1 mm long, each one shaped like a tiny six-sided capsule with concave sides. To the naked eye, they look like a fine, gritty powder similar to coarse sand, coffee grounds, or black pepper. Under a magnifying glass, though, the individual pellets are surprisingly uniform in size and shape.
The color of frass depends on the type of wood the colony is feeding on, ranging from light tan to dark brown or even black. A fresh pile typically forms a small, cone-shaped mound directly beneath the infested area. One distinctive feature: termite frass contains nothing but clean pellets. No wood splinters, no insect body parts, no food debris. Just gritty, uniform granules.
Where Frass Piles Appear
Drywood termites push their droppings out of the wood through “kick-out holes,” which are tiny circular openings less than 2 mm in diameter. These holes can appear on walls, ceilings, door frames, baseboards, or wooden furniture. Because the pellets are ejected from these openings, frass collects in small mounds directly below them, often on windowsills, countertops, floors, or inside closets.
The kick-out holes themselves can be hard to spot. They’re roughly the size of a pin tip and are sometimes sealed over by the termites after use. If you find a pile of what looks like fine sand or sawdust but can’t immediately see where it came from, look closely at the wood surface directly above. You may find one or more of these tiny holes.
One useful trick from pest inspectors: clean up the frass pile completely, then check the same spot a few days later. If new pellets have appeared, the infestation is active. Building vibrations can sometimes shake loose old pellets from previous infestations, so fresh accumulation is the more reliable indicator.
Termite Frass vs. Carpenter Ant Debris
Carpenter ants also leave behind wood-related waste, and the two get confused constantly. The differences are straightforward once you know what to look for.
- Texture: Termite frass feels fine and gritty, like coarse sand. Carpenter ant debris is coarser and more fibrous, with visible wood shavings and splinters.
- Shape: Termite pellets are uniform hexagonal capsules. Carpenter ant frass has no consistent shape.
- Contents: Termite frass is clean pellets only. Carpenter ant waste typically contains dead insect body parts, including legs, wings, and antennae fragments mixed in with the wood shavings.
- Color: Termite frass matches the wood being consumed (tan to dark brown). Carpenter ant debris tends to be lighter, often light brown to yellowish.
- Wood damage pattern: Carpenter ants carve smooth, oval-shaped galleries and prefer damp or decaying wood. Drywood termites leave kick-out holes in the wood surface, and the wood sounds hollow when you tap it.
If you see insect fragments mixed into the pile, you’re almost certainly dealing with carpenter ants rather than termites. If the granules are clean, uniform, and gritty, termites are the more likely culprit.
Other Signs That Confirm a Termite Problem
Frass is often the first visible clue, but it rarely appears in isolation. Drywood termites also shed their wings after swarming, so piles of small, translucent wings near windows, doors, or light fixtures are a strong supporting sign. Swarmers themselves sometimes emerge directly from walls, ceilings, or floors, usually in spring or early summer.
Structural clues can be subtler. Sunken or winding lines beneath paint or wallpaper often indicate termites feeding on the cardboard layer of drywall underneath. Termites eat the paper covering but leave the gypsum and the thin coat of paint intact, creating faint trails or depressions visible on the surface. You might also notice hollow-sounding wood when you knock on a door frame or baseboard, or spot BB-sized dots of dried mud on interior walls where termites accidentally broke through and patched the hole.
Subterranean termites, a different species, leave different evidence entirely. They don’t produce visible frass because they use their droppings to build their mud tubes and tunnels. Instead, the telltale sign is pencil-width mud shelter tubes running up your foundation, either on exterior walls or inside crawl spaces. If you’re finding mud tubes rather than pellet piles, you’re dealing with subterranean rather than drywood termites.
How Drywood Termite Treatment Works
Treatment depends on how widespread the infestation is. For localized colonies confined to one piece of furniture or a small section of wood, spot treatments applied directly to the affected area are common and relatively affordable, often in the range of $300 to $1,000. For larger or multi-colony infestations, whole-structure fumigation (tenting) is considered the most effective option. This involves covering the entire home with tarps and introducing a gas that penetrates all the wood. You’ll need to vacate the property for several days during the process, and costs run roughly $1 to $3 per square foot, putting a 2,500-square-foot home in the neighborhood of $6,000 or more.
The size and location of frass piles can give you a rough sense of scale. A single small mound beneath one kick-out hole may indicate a localized colony. Multiple piles in different rooms, or frass appearing in structural wood like ceiling joists or wall studs, suggests a more established problem that likely needs professional assessment. Either way, confirming whether the infestation is active (by watching for fresh pellet accumulation) is the critical first step before deciding on any treatment approach.