How to Get Rid of Carpenter Ants
A large black ant that nests in moist or damaged wood, including window frames, decks and wall voids. It doesn't eat wood but excavates smooth galleries and pushes out sawdust-like debris. If you are seeing them indoors and in woods and along trails, the steps below will help you clear them out and keep them from coming back.
Quick answer
- Follow trails at night to find the main nest and satellite colonies
- Fix leaks and replace water-damaged wood
- Use a slow-acting bait or call a professional for nests inside walls
Carpenter ants can deliver a painful bite and weaken wood over time, but they do not carry disease.
Confirm you have carpenter ants
Start by confirming the bug. Carpenter Ants have a few features that set them apart. Adults measure 6–13 mm (up to about 0.51 in) and are usually black and red. Look for these features:
- Large ant with an evenly rounded, single-arch thorax
- One node between the thorax and abdomen
- Piles of coarse sawdust and insect parts near nests
They are most often confused with eastern subterranean termite and pavement ant. See the full carpenter ant profile for side-by-side details.
Why you have carpenter ants
Carpenter Ants target wood, especially wood that is damp, damaged or touching soil. Leaky roofs, gutters and plumbing create the moisture they prefer. Woodpiles, stumps and mulch against the foundation act as a bridge into the house. They are most active in spring and summer, so expect to see more of them then.
When you'll see carpenter ants
Carpenter Ants are most active in spring and summer. In spring, overwintering adults become active and many species lay their first eggs. Summer heat speeds up development, so populations can grow quickly.
Typical places to check: indoors, anywhere, woods or trails, trees or shrubs and basement or garage.
Step-by-step: getting rid of carpenter ants
Step 1: Follow trails at night to find the main nest
Follow trails at night to find the main nest and satellite colonies. Combine this with the other steps rather than relying on it alone.
Step 2: Fix leaks
Fix leaks and replace water-damaged wood. Repeat this for at least two to three weeks, since eggs and hidden insects keep appearing for a while.
Step 3: Use a slow-acting bait or call a professional for nests inside walls
Use a slow-acting bait or call a professional for nests inside walls. Repeat this for at least two to three weeks, since eggs and hidden insects keep appearing for a while.
Natural and low-toxicity options
These methods work well alongside the steps above and keep chemical use to a minimum:
- Remove and replace wet or damaged wood.
- Fix leaks and improve drainage around the foundation.
- Move firewood and lumber away from the house and off the ground.
- For ants, use slow-acting baits rather than repellent sprays.
If you do use a pesticide, choose one labeled for this pest and the place you're treating, and follow the label exactly. The label is the law.
When to call a professional
Because damage often hides inside walls, get a professional inspection whenever you see carpenter ants indoors. With structural pests, early professional help usually saves money.
How to keep carpenter ants from coming back
- Keep at least six inches between soil and wood siding.
- Paint or seal exposed wood surfaces.
- Clean gutters and point downspouts away from the foundation.
- Schedule periodic inspections if you live in a high-risk area.
Safety notes
Carpenter ants can deliver a painful bite and weaken wood over time, but they do not carry disease.
Keep children and pets away from any traps, baits or treated areas.
About ants
The carpenter ant is one of the ants. Ants live in colonies ruled by one or more egg-laying queens. The workers you see are sterile females foraging for the rest of the colony, so killing visible ants rarely solves anything. Winged ants, called swarmers, appear when a mature colony sends out new kings and queens.
Bait works because workers carry it back and share it with the queen and larvae. Repellent sprays can scatter the colony and make the problem harder to fix.
Frequently asked questions
What is the fastest way to get rid of carpenter ants?
Follow trails at night to find the main nest and satellite colonies. Most people see a clear drop in activity within one to three weeks when they combine this with sealing entry points and removing whatever attracts them.
Are carpenter ants dangerous?
Carpenter ants can deliver a painful bite and weaken wood over time, but they do not carry disease.
When are carpenter ants most active?
Carpenter Ants are most active in spring and summer.
What do carpenter ants look like?
Large ant with an evenly rounded, single-arch thorax. Adults measure 6–13 mm (up to about 0.51 in).