How To Get Rid of Carpenter Ants: Exterminate Big Black Ants in the House

Georgette Kilgore headshot, wearing 8 Billion Trees shirt with forest in the background.Written by Georgette Kilgore

Pest Control | February 26, 2024

Man reading how to get rid of carpenter ants and finding natural ways to kill ants and exterminate big black ants in the house, as well as how to prevent ant infestation and find nests

While ants are intriguing creatures, learning how to get rid of Carpenter ants is essential if you don’t want them wandering around your home.

The desire to keep them out is especially the case for Carpenter ants, who unlike harmless Sugar ants, aren’t simply looking for food, and can seriously damage your home.

A Carpenter ant infestation should not be taken lightly, and if you suspect you have one, this guide can help you learn how to get rid of carpenter ants safely, and when and how you should call in a professional to treat then and prevent re-infestation.

What Are Carpenter Ants?

Carpenter ants came by their name because of their excavating activities. They make wood nests wherever possible.

Many people mistakenly believe Carpenter ants, like termites, eat wood, but this isn’t the case. While they eat their way through the wood to make tunnels, they don’t actually consume it.

With the help of a chart showing some of the tiny house bugs pictures and names, you’ll easily see the difference between these two house pests.

Carpenter Ant

(Campotonus pennyslvanicus)

Carpenter Ant in an oval frame on a green background
  • Natural Habitat: Dead and decaying wood in trees, stumps, logs, dead branches and weakened wood indoors.
  • Location: Eastern United States and Southeastern Canada

Their typical diet is plant juices, insects, and whatever human and pet food they find in your home. Ants of all kinds have a sweet tooth.

Aphids are their insect of choice for the sugary substance they produce, and their favorite human foods include sugar, jelly, syrup, and honey. However if you have ever observed ants of any kind in your home, they will pretty much feast on any scraps they find lying around your floor or countertop.

Carpenter ants are one of the largest, typically measuring ⅜ to ¾ inch long.1

Seeing long trails of ants in your home might make you wonder, how many ants are in the world? A lot!

Carpenter ants alone have several species that vary in color from yellow to black to reddish brown. Their jaws are very large, which is why they are so good at chewing wood.

Graphic of a Carpenter Ant identification displaying a detailed image of a carpenter ant with labeled features such as pinched waist, rounded thorax, large jaws, six legs, and a size reference of 3/8 to 3/4 inch.

They have a pinched waist and two sets of wings. The back wings are shorter than the front wings.

How To Get Rid of Carpenter Ants: Finding the Nest

If you don’t destroy Carpenter ant nests, the ants will keep coming, leaving you constantly on defense, trying to keep them out of the house.

The queen will keep laying eggs in the parent nest, and more and more satellite nests, full of the worker ants, will keep popping up.

The fact Carpenter ants usually have multiple nests in a location is one of the reasons it can be difficult to remove them.

You can’t find the nest if you aren’t able to observe the Carpenter ants’ movements,2 so don’t kill the first ones you see right away. They will be moving about, laying scent trails that alert the other ants where to find food.

This step of the process may require patience.

You may see the ants moving towards baseboards, cabinets, doors and other wooded structures. They may have set up shop outside in wood piles, dead trees or tree stumps.

They particularly like moist, humid environments because it is in these conditions their nests thrive best. So it is typical to find the nests in bathrooms, basements, dryer rooms or other spaces prone to water leaks or higher moisture levels.

If you have seen evidence of Carpenter ants in your home, such as wood shavings, but have yet to see them, you’ll need to lure the ants out by laying bait with sweet treats like diluted honey, jelly, or jam. If you want to kill the ants at the same time, mix sugar and baking soda.

Carpenter ants are creatures of the night, so put the bait out in the evening and wait for them to come out.

You may also identify the nest by listening for rustling sounds.

If you suspect a nest in a certain area, tap on it to see if you hear the hollow sound of damaged wood. If so, there’s a good chance your suspicions are correct.

5 Signs of Infestation

Detecting signs of infestation early makes it simpler to eliminate Carpenter ants.

1. Seeing the Ants in Your Home

The most obvious sign of infestation is seeing the ants in your home.

The worker ants leave the colony to find food sources, and that is where your house comes in. They enter the space and lay their scent trails so the other ants in the colony know where they can find sustenance.

A close-up of a winged carpenter ant on a countertop.

(Image: Eli Duke6)

If you see the ants inside during the winter and earlier in the spring, there is a good chance the nest is inside the house unless they were living in firewood stored outside that you brought into the house. At other times of the year, it is harder to tell where the nest is located.

2. Seeing Ant Wings

Following their mating phase, winged Carpenter ants shed their wings.

You’ll often find these discarded wings close to doors and windows in particular.

3. Wood Shavings

Remember that Carpenter ants don’t eat wood, they tunnel through it to make their nests.

If you have an infestation, you will see wood debris or shavings, referred to as ‘frass’ on the ground and along walls, especially under wooden items.

4. Seeing Small Holes in the Wood

As the Carpenter ants eat through the wood to make their nest, they must discard the debris.

To get rid of it, they make tiny, pinhole size openings in the wood to push out the frass and continue to tunnel through.

5. Swarm of Winged Ants

If you see a large swarm of winged ants in the spring, you not only have a nest nearby, you have a parent nest that has been there for at least two years.

How To Get Rid of Carpenter Ants: Getting Rid of the Ants

Learning how to get rid of carpenter ants involves a variety of options.

Here are some strategies and insights to help you eliminate Carpenter ants:


Pyrethrin is the most common pesticide used to destroy Carpenter ant nests.3 While you may associate pesticides with toxic chemicals, pyrethrin is a natural substance found in chrysanthemum flowers, which is good news for the growing number of people who prefer to keep their homes free of harsh, man-made chemical products.

Pyrethrin kills the ants by stimulating the nervous system, inducing paralysis and death. It works well for many other insects, and you will find it in the ‘tool kit’ of many organic gardeners.

Using pyrethrin requires you to drill holes near the nest and spray or dust it directly into the colony. You can also place it in any crevices nearby.

Graphic on how to get rid of carpenter ants showing methods including a Pyrethrin spray, Borax and Boric acid, ant baits, and desiccants, with illustrations of ants on green leaves.

While natural substances are generally safer than synthetic, they can have their dangers too. Pyrethrin is considered a neurotoxin, so use it with care.

Some people may have an allergic reaction, especially those suffering with asthma. If a person or pet accidentally ingests pyrethrin, call a poison control center immediately.

If your preference for pyrethrin is primarily due to its organic properties, do not buy pesticides labeled ‘pyrethroids.’ These products blend the pyrethrin with non-organic chemicals meant to enhance its effectiveness.

If you use these products, know they are not as safe as pure pyrethrin and require more caution. Examples include cypermethrin, bifenthrin, and gamma cyhalothrin.

If you use the liquid form, do not spray it on electrical outlets or near junction boxes, though you can use the dust version of the pesticide in such places.

Do not use pyrethrin directly on individual ants you see–this will not help in any meaningful way. You must apply it to the nest and destroy the colony.

Borax and Boric Acid

Borax, a naturally occurring mineral, and boric acid, a refined substance made from borax, is another natural option for those who prefer greener pest control methods. Though boric acid is a natural substance, many people don’t regard it as organic because of the heavy refinement process required for its production.

Like pyrethrin, you can use boric acid dust directly on the nests by ‘puffing’ it into crevices and holes you drill in the wood. The product will typically come with an applicator you use for such purposes.

You can also use borax for bait traps. You mix it with a sweet substance the worker ants will feed on and bring back to the colony, where the other ants will eat it and die.

Borax’s ant-killing properties lie in its ability to interfere with the ant’s digestive process. This method is not a quick one though and can take several weeks of baiting to eradicate an entire colony.


Like the borax-specific traps mentioned above, there are many types of substances used to bait ants and bring the lethal substances back to the nests.

Ants can be a bit picky with the baits, and it may require trial and error to find the ones that will attract them most effectively.

A white ant bait station, used as a method of pest control for carpenter ants, placed against a corner, surrounded by numerous ants attracted to it.

(Image: Thmazing8)

Baiting is a slower method in general and can be made even more so by the possibility it will take a while to find ones that draw the ants. There are specific baits for Carpenter ants, so do not buy the generic ones.


Desiccants dehydrate the ants by destroying the outer protective layer of their bodies by absorbing its waxy coating.

Silica gel is highly effective, but you cannot use it yourself, only licensed exterminators can apply it. However, you can buy aerosol products that typically contain a mix of silicon and pyrethrin.

For a DIY option, use diatomaceous earth, a natural, non-toxic substance safe for people and animals, as long as you choose food grade.4

Do not breathe in the dust, as it can cause lung damage. Though this probably isn’t a concern unless you were around it frequently.

The application method is the same as the pyrethrin and boric acid dust mentioned above.

Diatomaceous earth is one of the most effective Carpenter ant treatments because of its ability to deeply infiltrate the cracks and crevices in the walls.

How To Get Rid of Carpenter Ants: Considerations for Repellant Substances

While products that will repel ants have their purpose, they are not what will help you deal with active infestations and should not be the focus right now.

Once you have the problem under control, then turn your attention to how to keep them away in the first place.

Erasing Scent Trails

Carpenter ants, like all other ants, release pheromones as they travel along your home to find their way back to any food sources and let their brothers and sisters back in the colony know where they can go to chow down.

Once the ants have gone from your home, eliminating their scent trails will reduce the chances of them coming back, making this strategy an important part of your process.

Keeping these surfaces clean removes these chemical markers, but it is insufficient to sweep them free of any food or wipe them down with water. You must completely remove the scent, particularly the points of the home at which they are entering.

Luckily, there are several substances that can help with how to get rid of Carpenter ants effectively.

  • Essential Oils: Put the essential oil on a cotton ball and wipe down surfaces. Good choices include orange, cedar wood, tea tree, and lemon
  • Solutions: Fill a spray bottle with one part dish soap to two parts water or a 50/50 solution of water and white vinegar. The dish soap solution also directly kills ants.
    If you use the vinegar solution, do not wipe it afterwards; let it dry naturally. Ammonia solutions will also work well.
    The one thing that won’t work is bleach.

How To Get Rid of Carpenter Ants: When To Call a Professional

There are no hard and fast rules for determining when you should call an exterminator to remove Carpenter ants versus attempting to do it yourself,5 and if you choose the do it on your own route for how to get rid of Carpenter ants and don’t see successful results, it might be time to consult a professional.

Generally, if you see large numbers of ants swarming inside your house during spring and early summer, this usually indicates a significant infestation in your walls. Destroying the central nest, which contains the egg-laying queen, on your own may be difficult, and the ants will keep coming, and keep establishing ‘satellite’ nests full of worker ants.

It can take at least a couple of weeks to get rid of the ants with self-treatment, perhaps longer depending on the level of infestation and the methods used. If you don’t seem to be making much headway after a few weeks, it might be a good idea to call an exterminator specializing in Carpenter ant removal.

Carpenter ant removal is the most expensive treatment of all types of ant removal, and generally ranges from $250 to $500, depending on the extent of the infestation and where you live.

Generally, one treatment should get the problem under control, but you may need to spray every few months or so to keep your home truly free of them. If your home seems more vulnerable to these ants for whatever reason, being diligent about preventative measures becomes even more important.

How Can I Prevent Carpenter Ants?

As they say, an ounce of prevention is worth a pound of cure, and considering how damaging Carpenter ants can be, taking measures that prevent them from making your home their home is paramount. Like a moth to a flame, so is a Carpenter ant to decaying wood.

Regularly check your home for rotting wood and replace it promptly, especially any wood adjacent to gutters and drains. You must properly seal all siding and foundation holes.

Big black ants in house, specifically carpenter ants with reddish-brown bodies, move across a textured wood surface, with one ant close to a hole.

(Image: Camera-man7)

Cap with metal any wood that comes into contact with the soil. Using borate-treated lumber for siding and wall framing will discourage them from taking a foothold.

Clear away wood piles, tree trimmings, and other wood that can host a colony. Keep firewood outside, and give it a good shake before bringing it in.

Why Are They a Problem?

Carpenter ants establish their nests by chewing through moist, soft, rotting wood inside or outside the home. The damaged wood itself is the true problem, but the presence of the ants accelerates the structural damage by further weakening it.

While they prefer damaged wood, they are known to target sound undamaged wood as well, which furthers the risk of damage to your house by weakening support beams and other important structures inside your home.

Carpenter ants generally do less damage than termites because it is easier to spot their presence. They don’t eat the wood but rather expel it through small holes.

So you will see this sawdust on the floors and walls, whereas a termite would eat the ‘evidence.’

Infestation with Carpenter ants is definitely a problem that requires immediate attention, but it is a problem with effective solutions.

If you’re not inclined to handle the infestation yourself or your DIY approach doesn’t seem to be bearing fruit, it might be time to consult a professional on how to get rid of Carpenter ants.

Frequently Asked Questions About How To Get Rid of Carpenter Ants

How Many Ants in a Colony?

The parent nest contains the brood, the larvae and 2,000 or more worker ants. Satellite nests, of which there can be several near the parent nets, can have thousands each; a typical ant colony can have over 10,000 ants.

Do Carpenter Ants Carry Disease?

While Carpenter ants can certainly damage your home, luckily they won’t damage your health. They can track bacteria in the home, but their pretty benign diet, plant juices and other insects, means they really aren’t excreting anything too harmful.

Do Carpenter Ants Bite?

They have very strong jaws, and yes, they have been known to bite which can be painful, particularly if they inject formic acid, a component of venom in ant and bee stings, into your skin. It may hurt and burn for a bit, but the bites do not cause serious or lasting damage.


1Jacobs, S. (2023, April 14). Carpenter Ants. Penn State Extension. Retrieved October 20, 2023, from <>

2Potter, M. (1997, November). Carpenter Ants. UK Martin-Gatton | Entomology. Retrieved October 20, 2023, from <>

3U.S. Department of Health & Human Services. (2014, March 25). Public Health Statement for Pyrethrins and Pyrethroids. CDC | ATSDR. Retrieved October 20, 2023, from <>

4Oregon State University, & U.S. Environmental Protection Agency. (2013, January). Diatomaceous Earth Fact Sheet. National Pesticide Information Center. Retrieved October 20, 2023, from <>

5Klotz, J. H., Rust, M. K., & Hansen, L. D. (2009, August). Carpenter Ants. UC IPM. Retrieved October 20, 2023, from <>

6Photo by Eli Duke. CC BY-SA 2.0 Deed. Resized and Changed Format. Flickr. Retrieved from <>

7Photo by Camera-man. Pixabay. Retrieved from <>

8Photo by Thmazing. Wikimedia Commons. Retrieved from <>

9Species Information Image: A bug on a stick Photo by VD Photography. (2022, July 11) / Unsplash License. Cropped and added text, shape, and background elements. Unsplash. Retrieved February 26, 2024, from <>