How do you get rid of carpenter ants?

closeup of carpenter ants on tree

As far as pests go, carpenter ants are one of the worst. Like normal ants, they can get into your food and have painful bites. On top of that, they build nests in wood structures, which causes significant damage if they get into the wood beams in your walls and roof. 

If you have them, you already know what a nuisance they can be. So how do you get rid of carpenter ants? In many cases, you’ll need help from a professional exterminator. But there are some DIY methods you can try first. 

How to get rid of carpenter ants 

close up of a carpenter ant on leaf
Judy Gallagher | Flickr | CC BY 2.0

A carpenter ant infestation can be difficult to shake because they burrow deep into wood to make their nests. You have to use different methods than you would use to get rid of other types of ants

It’s highly likely that you’ll need help from a pest control professional, especially if the carpenter ants are nesting in your home’s structure. If you’re reluctant to call a professional, here are some steps you can take to try and eliminate the infestation yourself. 

Step 1: Find the nest

Ants live in huge colonies, so wiping out a few ants at a time won’t get you anywhere. To end an infestation, you have to target the nest. And to do that, you have to find the nest first. 

Carpenter ants always nest in wood. They love moist and decaying wood, so any damp spot is a prime target. But that doesn’t mean they can’t nest in dry wood. The most common locations you might find a nest in your home or yard are:

  • Wall voids
  • Roof beams 
  • Behind dishwashers
  • Behind air conditioning units
  • Firewood piles 
  • Tree stumps
  • Tree roots
  • Fallen trees or logs

If you see a line of carpenter ants foraging in your home or yard, you may be able to follow them to the nest. You can also look for signs of carpenter ants, such as piles of sawdust or rustling sounds coming from inside a wall or wooden structure. 

Step 2: Destroy the nest

Destroying the nest is where carpenter ant extermination gets tricky. First, you have to drill holes every 6 inches in the wall or structure where you suspect a nest. Then, use a bulb duster (a special pest control tool) to inject an insecticide into the holes. 

If you want to use a chemical pesticide that you buy from a store or online, make sure you choose one labeled for use against carpenter ants. You don’t have to opt for chemicals right away, though. There are eco-friendly insecticides you can try, such as:

  • Diatomaceous earth (DE)
  • Boric acid 
  • Borax

Once you’ve covered the nest area with insecticide, there should be less carpenter ant activity. Keep in mind that carpenter ants often build satellite nests along with the main one, so you may have to repeat this process several times. 

Step 3: Set up ant baits

closeup of ants at bait card
Forest Starr and Kim Starr | Flickr | CC BY 2.0

The insecticide you spread around the nest will only work on the ants that come in direct contact with it. If you want to reach the ants deep inside the nest (especially the queen), you have to set up ant baits, too. 

Ant baits (aka ant traps) include a substance that the ants want to eat and a poison that will cause them to die. They carry the “food” back to the nest to share with the entire colony, and they share the poison at the same time. 

You can buy commercial carpenter ant baits that use chemicals or make your own DIY ant baits. To make your own baits, mix a sweet substance (syrup, sugar, peanut butter, or something similar) with a substance that’s poisonous to ants, such as:

  • Artificial sweeteners containing aspartame or saccharin
  • Baking soda
  • Borax
  • Boric acid 

Whether you buy chemical baits or make your own DIY versions, place several baits for maximum efficiency. Set them up near the nest, all along ant trails, and in any areas where you’ve seen ants foraging for food. 

Step 4: Erase pheromone trails 

Carpenter ants communicate through pheromone trails, also known as scent trails. These trails lead them to food sources (like your pantry) and back to the nest. Cover those scent trails with ant repellent to confuse ants and keep them from returning to your kitchen for more food. 

Some ant repellents you likely already have around the house are:

  • Cayenne pepper or black pepper
  • Vinegar
  • Cinnamon

Find more natural DIY ant repellents in our guide to repelling ants in your yard and home naturally.

How can you locate carpenter ants’ scent trails? Look for lines of ants marching in a row. They are following a scent trail. Applying repellents all around the nest area and areas of your home with food is another option. 

Step 5: Call an exterminator 

If you try all the steps listed above and you still have carpenter ants, you likely have a larger infestation than you can handle on your own. At this point, you should call a pest control professional. 

Remember, carpenter ants can have multiple active nests at once, and those nests could be anywhere on your property, either inside or outside your home. Professional exterminators have the tools and expertise to find and wipe out nests that are difficult to locate. 

Don’t put off calling an exterminator if carpenter ants are inside your home. Act now before their tunneling causes serious structural damage that will be expensive to repair. 

How to prevent carpenter ants

With a few simple practices, you can prevent carpenter ants from ever infesting your yard and home in the first place. 

Eliminate moist wood

Carpenter ants need three things in a nesting location: wood to build the nest in, steady water sources, and a food source. Moist wood provides two of those requirements. If you get rid of any moist wood in and around your home, carpenter ants are less likely to infest. 

Here’s how you can do that:

  • Remove decaying logs, tree stumps, and fallen tree limbs from your yard ASAP.
  • Store woodpiles in a dry, covered location. 
  • Keep an eye on the walls behind dishwashers, air conditioning units, sinks, bathtubs, and other hidden spots where walls can easily get wet. 
  • Replace water-damaged wooden beams ASAP. 

Don’t let any outdoor wood touch your house. That includes woodpiles and live tree branches. Carpenter ants can use wood touching your house as a bridge to get inside the walls. 

Keep food secure

Sweets, meats, and other foods can attract carpenter ants just as they attract other ants. 

To prevent carpenter ants in your yard, dispose of food waste in trash cans or compost bins with secure lids. Store cans and bins away from the lawn, where carpenter ants are more likely to find them. 

To prevent carpenter ants in your home, clean up food scraps immediately. Don’t let crumbs or dirty dishes sit out. Store food in the fridge or in airtight containers in the pantry. 

Use repellents

hand holding eyedropper putting essential oil in bottle
Formulate Health | Flickr | CC BY 2.0

Spread ant repellents around your property. You can use chemical perimeter treatments or create a barrier with natural repellents. When creating a barrier, spread the repellent around outdoor living spaces and entry points into your home such as doors, windowsills, and pipes.

Here are some effective ant repellents you can try:

  • Some essential oils (peppermint, cedarwood, and tea tree, to name a few)
  • Vinegar
  • Black pepper or cayenne pepper
  • Chili powder
  • Lemon juice
  • Citrus peels
  • Cinnamon

Signs of carpenter ant infestation

How can you tell if carpenter ants have infested your home or yard? Here are the most common signs of carpenter ants. 

Frass

Frass is the word for the piles of sawdust that carpenter ants leave behind when they tunnel into wood. If you see wood shavings near a wall, tree, fence, or other wood structure, that could mean you have carpenter ants.

Rustling noise 

Sometimes, you can actually hear carpenter ants moving around inside wood. Press your ear against the wall or structure where you suspect a nest and listen for a faint rustling noise. 

Discarded wings

Reproductive carpenter ants only need their wings during their mating season in spring. After mating, they all shed their wings. That means you could find large numbers of discarded wings around your yard and home if you have carpenter ants. 

Ant trails 

Have you seen rows of large black ants crawling in or around your home? It could be carpenter ants. 

Carpenter ants travel up to 300 feet to forage for food, so if you see an ant trail, the infestation could be anywhere on your property, indoors or outdoors. It may be difficult to follow the ants back to their nest.

How to identify carpenter ants 

There are many different types of ants that commonly invade homes and gardens. All of them are a nuisance, but most of them aren’t wood-boring, so they aren’t as serious a threat as carpenter ants. 

Carpenter ants vs. other ants

How can you tell if the ants you’ve seen around your property lately are carpenter ants or a less harmful ant species? Here are some identifying features to look for: 

  • Size: Carpenter ants are large compared to other ants at about 9.5 to 13 millimeters long (about the width of your fingernail). 
  • Color: Carpenter ants are usually all black, but some can be red and black. 
  • Shape: A carpenter ant’s head is shaped like a heart, while the abdomen (the equivalent of an ant’s butt) is round and bulbous. The thorax (middle section) is skinnier than the head and abdomen. 
  • Active period: Carpenter ants are typically active only after dark. If your ants are out during the day, they probably aren’t carpenter ants. 

Carpenter ants vs. termites

closeup of termite mound
Katja Schulz | Flickr | CC BY 2.0

Many homeowners confuse carpenter ants with termites. The two insects don’t really look alike, but people see wood shavings and assume they have termites most of the time

Here are some easy ways to figure out if you have carpenter ants or termites:

  • Body shape: While carpenter ants have a large head and abdomen with a narrow thorax, termite bodies are about the same width from top to bottom. 
  • Antennae: Carpenter ants (like all ants) have bent antennae, while termites have straight antennae. 
  • Wings: Winged carpenter ants have two sets of wings, and the wings are about the same length as their body. Winged termites also have two sets of wings, but they extend about twice the length of the termite’s body when closed. 
  • Signs: Remember that carpenter ants leave piles of sawdust or shredded wood outside their nests. Termites eat wood as they move through it, so they don’t leave any behind. Instead, they leave piles of tiny fecal pellets that look like coarse dirt. 

For more help distinguishing between termites and other wood-boring insects like carpenter ants, see our guide to bugs that look like termites

Carpenter ant behaviors

If you want to eliminate carpenter ants effectively, you have to understand them. Here are some facts about how carpenter ant colonies function to help you form your pest control plan. 

Nests

Carpenter ants don’t eat wood like termites do. Instead, they drill vast tunnel systems (if given the time) in the wood to create their nests. They usually begin their nests in wet, decaying, or moldy wood. From there, they can move on to dry, healthy wood. 

Carpenter ants build their main nest, where the queen and eggs stay, first. Once the parent colony has been established for a few years, they branch out and build smaller satellite colonies, where worker ants live, in case the main nest is destroyed. 

Indoor nests are often satellite nests. If you have a satellite colony living in your home, the parent colony is likely in your yard somewhere. You have to find and destroy the main nest and the queen to wipe out an entire colony permanently.

Swarming 

Swarming is a mating habit of many insects, including carpenter ants. When reproductive carpenter ants reach maturity, they fly away from their original nest in an attempt to mate and begin a new nest somewhere else. After swarming, they shed their wings. 

It’s called “swarming” because all the carpenter ants in an area mate at the same time, so there are large numbers of them flying around during that time. Mating season varies depending on the weather, but it usually occurs in spring

Eating habits

Outdoors, carpenter ants feed on the juices of plants and fruits, honeydew (a substance produced by aphids), and live or dead insects. 

If carpenter ants get into your home, though, they’re happy to feed on most of the foods in your pantry. They’ll go after anything sweet, as well as meat products and greasy foods. 

In either case, you should only see carpenter ants outside of the nest and foraging for food at nighttime.

Bites 

Wondering if you should be worried about carpenter ants biting you? The answer is yes, carpenter ants will bite you if you disturb them. And those bites will hurt. 

Carpenter ants have especially painful bites for two reasons. One is their size. Because carpenter ants are larger than most ants, their mandibles (jaws) are larger and can break the skin. Their bites are even more painful because they release formic acid into the open wound. 

Final word on carpenter ants

Carpenter ants in your yard don’t have to be a huge problem, as long as you take steps to prevent them from getting into your home. In fact, carpenter ants, like other ants, can be helpful because they prey on other pest insects.

But if carpenter ants are living inside or even near your home, exterminate them immediately. Like termites, carpenter ants will be an expensive and long-lasting thorn in your side if they get into the wood structure of your house. 

You can try the DIY pest control methods we suggested here, but ultimately, we recommend calling a pest control professional, at least for an inspection of your walls. 

You don’t want to think you’ve solved your carpenter ant problem only to find out you didn’t exterminate them all and years later you have extensive — and expensive — damage to your home.

A simple way to prevent pests from making a home in your lawn is to maintain your property, including keeping the lawn trimmed and the debris away. Lawn Love pros can help in any manner of lawn care in order to keep your home pest-free.

Main Photo Credit: Judy Gallagher | Flickr | CC BY 2.0

Jordan Ardoin

Jordan Ardoin is a writer and indoor plant enthusiast hailing from Florida. In her spare time, she enjoys chasing her two cats around the house and trying to keep her houseplants alive.