Carpenter Ants: How to Rid Them From Your Home

Before you begin your battle with carpenter ants, remember that not all pesticides are legal everywhere or even considered safe. Consult your local regulations and ensure you use pesticides per the manufacturer’s recommendations.

My war with carpenter ants began with an ignorant act on my part. I brought firewood into my home, which was infested with giant black ants. Ants I should have noticed and identified as carpenter ants. Top it off, some of that wood contained powder post beetles.

Within a few months, I fought a losing battle and spent thousands of dollars on pest removal services and sprays.

Fortunately, the war is now over. But, I won by first identifying the pests causing the problem, learning where they lived, and what they needed to survive.

Then, I learned how to kill them and, finally, how to keep them away from the exterior of my home.

Related: What do ants eat?

Carpenter ants
Firewood with carpenter ant damage and infestation. Photo credit: Larsson.

Basic information about carpenter ants.

Carpenter ants (Camponotus) actually come in different colors (mostly black in my house) and sizes but typically are larger than other ants (up to 1/2 inch for males and 3/4 inch for queens) and easily recognized. 

A carpenter ant does not eat your home’s wood. Instead, carpenter ants eat the things it finds inside your home.

Carpenter ants are primarily foragers. They emerge from the nests at night to find, collect, and consume dead insects and any sugary items they might discover. 

How to find carpenter ants in your home.

Carpenter ants make their nests in dry wood (like my improperly stored and seasoned firewood). However, they prefer moist wood. Therefore, seasoning firewood directly on the ground or allowing your home’s wood to be exposed to water leaks from sinks, exterior faucets, and bathtubs provides a suitable place for black ants to establish a home base inside your home.

Once carpenter ants have taken up residence, they can be hard to detect. Often, the only external sign of carpenter ants is frass. Frass is the chewed, removed wooden shavings carpenter ants leave behind as they build their galleries. 

Frass looks like sawdust, and you’ll find it in mounds just outside the entrance to a carpenter ant’s newest.

Carpenter ant frass
Carpenter ant frass. Photo credit: Martin

If you catch a carpenter ant foraging in your house, you may need to try and locate its nest by tapping any wood surfaces that come into contact with your floor.

It is possible to hear the damaged hollow thud made by wood damaged by carpenter ants or even hear their jostled response with your ears. The workers may respond to taps by striking their mandibles and abdomen against the gallery walls to warn other colony members.

Their chewing and warning alarm signals can sometimes be loud enough to hear without assistance. However, I recommend purchasing a cheap stethoscope to tap and listen, tap and listen, as you make your way across the room.

If you have a severe infestation in the springtime, you might also notice winged carpenter ants swarming inside your house. You can tell the difference between winged carpenter ants and termites by how much larger they are and by the shape of their wings.

The amount of damage carpenter ants will depend on how quickly you find them, how many nests they have built inside your home, and how long the infestation has been underway.

Remember, carpenter ants do not eat wood; the damage the cause is the tunneling they do to create their galleries. These galleries are connected by smooth tunnels bored through wood, insulation, and other materials. Here is what you might see after uncovering a carpenter ant’s handiwork.

Carpenter ants
Carpenter ant damage to insulation. Photo credit:

Carpenter ant nests.

Carpenter ants can build a nest both inside and outside of your home. But, unfortunately, the carpenter ants who smuggled their way onto my three-season porch didn’t find much to eat.

These carpenter ants were quickly noticed due to their need to undertake extended foraging expeditions. Unfortunately, my porch lacked the moisture or food sources needed to establish a large nest.

Carpenter ants usually build two nests, a parent colony, and a satellite colony. The parent colony will house the queens and a few thousand workers ants. The satellite colony will hold thousands of workers.

Any carpenter ant colonies in your home are probably satellite colonies. So these will be your first targets. After that, you’ll need to get outside and find that parent colony and take steps to prevent the reentry of future carpenter ants.

Satellite colonies in your home can be found behind the bathroom and kitchen walls (thinking condensation and leaks from pipes, or moist, rotting wood exposed to leaking roofs and gutters.

Look for parent colonies in firewood piles, tree stumps, and woodpiles. Here the carpenter ants will have access to all the moisture and dead insects they need to establish and maintain a smaller parent colony.

Keeping carpenter ants out of your home.

For me and those who heat their homes with firewood, check the wood before bringing it inside. It is also wise to store your firewood well away from the house and elevated to prevent direct contact with the ground.

The key to keeping carpenter ants outside of your home is deny them the water they need to survive. This means caulking cracks and openings around your windows and doors, cutting back vegetation and branches, and removing pools and puddles of standing water against your foundation.

A properly sealed home means even if you bring carpenter ants inside, they can’t get to a water source outside.

How to get rid of carpenter ants in the house.

The only way to get rid of carpenter ants in your house is to find their nests. But, unfortunately, the only way to find their nests is to follow them home like you were a cop in an old movie.

Place some sugary bait where they will eventually find it, and sit back and wait. It may take a few days for the carpenter ants to find the bait, and you may not catch them at it right away. If needed, keep adding bait.

Eventually, some lucky carpenter ant will find your sugary treat and leave a scent trail back to the nest. Once it gets home, all the other ants will head for that bait pile like carb-seeking missiles.
Now you just have to put a tail on them. Those carpenter ants returning home should lead you to a crack or opening between the floor and a wall or behind a cabinet before disappearing.

Now all you have to do is drill a series of small holes (just big enough to admit the nozzle of a boric acid applicator) to cover a 5-foot wide area around the carpenter ants’ entry point. This should allow you to puff enough boric acid into the void and come into contact with most of the nest.

Using boric acid works best because even if the nest is outside, the poisonous boric acid doesn’t kill the carpenter ant until well after it has returned the delicious poison to its nest and fed its queen and other workers. Boric acid is a foraging ant’s worst enemy—it tastes delicious but kills them.

Dealing with carpenter ants outside your home.

Finding an outdoor nest is tricky. Grab a flashlight and inspect the outside of your home’s foundation. Any penetrations in your foundation should be checked for carpenter ants headed inside to forage in your kitchen.

Where possible, consider using a pest-blocking foam (I love this stuff) to seal off cracks and open spaces where pipes or utility pipes enter the foundation.

Once you find a nest outdoors, apply some Seven Dust per the manufacturer’s instructions.

Carpenter ant Carpenter ants
Close up of a carpenter ant. Photo credit:

Can a carpenter ant hurt you?

Carpenter ant bites do not normally require any special medical treatment. Use first aid and wash and clean the bitten area if needed. If there is any swelling or lingering pain, contact your physician.

Dennis V. Gilmore Jr.

Dennis V. Gilmore Jr. is a former Marine Sergeant and the author of several books, including two on night hunting coyotes and red and gray fox. He has written several hundred articles on predator hunting for

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