Fix it
What are these sawdust piles? Carpenter ants?
A neat little cone of what looks like sawdust, appearing where nobody sanded anything, is excavation debris — something is mining your wood. Whether it is carpenter ants or something else is readable from the pile itself.
What it usually is
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Carpenter ant frass: fluffy wood shavings with insect parts
Carpenter ants do not eat wood; they carve galleries and dump the shavings out slit-like windows. The pile is fibrous, mixed with fragments of dead ants — and it reappears after sweeping, which is the activity test.
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Drywood termite pellets imitating sawdust
Termite frass is granular, six-sided pellets like coarse sand rather than fluff — a magnifier or a macro photo tells them apart in seconds, and the distinction changes the treatment entirely.
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Moisture-damaged wood attracting the colony
Carpenter ants choose soft, damp wood: around chronic leaks, at sill plates, behind poorly-sealed thresholds. The pile marks the symptom; the moisture is the invitation.
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The parent colony commuting from outside
Big ants trailing at dusk between the house and a stump or woodpile means the main colony lives outdoors with a satellite in your wall — the trail is diagnostic gold, so follow it before treating anything.
What you can check yourself
Photograph the pile close-up, sweep it, and date the reappearance. At dusk, watch for trailing ants and note where they enter. Fix the moisture source — the leak or contact point that softened the wood — because treatment without it invites the next colony. Baits can work on minor satellite activity; give them weeks, not days.
When it’s a job for a pro
Locating and treating the nest galleries — and distinguishing ant from termite definitively — is inspection work with real stakes, since the wrong DIY spray scatters carpenter ants into multiple satellites. Reappearing frass or a visible trail is a call worth making promptly.
Carpenter ant treatment typically runs $250 to $600; a combined inspection that also rules termites in or out is the two-birds visit at $75 to $200, often credited to treatment.
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