How to get rid of carpenter ants in 5 easy steps

Key points

• Unlike termites, carpenter ants do not eat wood, but they do burrow into wood.

• Carpenter ants can cause extensive and costly damage by jeopardizing wood structures.

• Piles of powdery wood shavings, called frass, are a sign you have a carpenter ant infestation.

Spotting a trail of large black carpenter ants will give anyone the creepy crawlies. But the Camponotus genus, known for several species of carpenter ants, is not only pesky, it can wreak havoc on your house — and your bank account. 

Carpenter ants excavate extensive galleries, or burrows, inside wood. This is why you want to learn how to get rid of carpenter ants as soon as possible. “When carpenter ants move into the wood within your homes their status changes from that of a beneficial creature that helps to break down dead or injured trees in the environment to that of a pest with the capacity to do a lot of expensive structural damage within your home,” said Craig Sansig, service director, Viking Pest Control in Basking Ridge, New Jersey. 

Yet unlike termites, carpenter ants don’t eat wood. Their dietary preferences include carbohydrates and proteins in the form of insects and honeydew (droppings from sap-sucking insects like aphids and spotted lanternfly), Sansig said. These pests can also be attracted to sugar foods, greasy leftovers and pet food. 

Treatment for these two pests is different and not likely to be effective if applied to the incorrect species. “Termites also tend to be more expensive to treat than carpenter ants,” Sansig added. It’s important you’re identifying properly.

Worker carpenter ants are typically jet black and range from one-quarter inch to one-half inch long. They have a bulbous arch-shaped thorax. Some carpenter ants, such as Camponotus floridanus have a rust-colored thorax and head. Similar to termites, these insects swarm between April and June. 

Standard ant bait won’t help with a carpenter ant infestation, and homeowners insurance policies and home warranty companies do not cover damage caused by wood-destroying insects. If you think you have carpenter ants in your home, you should enlist the help of professional pest control right away. 

Here’s how to get rid of carpenter ants, what causes an infestation and the best way to say goodbye to these wood-wrecking pests. 

How do you know you have a carpenter ant infestation?

If you see a pest, you have a pest. “The most obvious sign of a carpenter ant problem is seeing carpenter ants in or around your home,” said Emma Grace Crumbley, entomologist at Mosquito Squad, a natural pest control company. Of course, this matter can be a bit complicated for the layperson as carpenter ants can be commonly confused with termites. You may even mistake them for other types of ants such as black or fire ants.

Here are some telltale signs of a carpenter ant infestation. 

• Powdery residue: These ants construct their nests in wood, the primary component in home structures. “Mouthful by mouthful, they remove and spit out small amounts of wood shavings, called frass, near their nest,” Sansig said. Frass is similar to sawdust, but not as coarse. You’ll see it accumulate near nests. It is often intermixed with insect pieces and other debris. These detritus wood piles often appear around windowsill ledges, baseboards, door frames, fireplaces or tree stumps that host a satellite colony.
• Small “window” holes in wood: Watch out for openings that look as if they were cut against the wood grain, along with piles of sawdust and debris spilling out of these holes. “Carpenter ants’ galleries are usually cleaner than termites’, so if the damaged wood has clean, almost sanded looking channels, it’s likely you have carpenter ants,” Crumbley said.
• Visible water damage: While it’s not always the case, in most instances, carpenter ants prefer to build nests in wood that is easy to tunnel through. These creatures typically favor damaged wood that has started to decay from moisture problems, which “provides them with a recurring source of moisture,” said Scot Hodges, vice president of professional development and technical services at Arrow Exterminators in Atlanta.
• Rustling sounds in walls: You may hear slight sounds of ants moving or rustling around in wall voids or in the case of a severe infestation. “If you hear scratching or chewing however, you may be dealing with a rodent problem,” Crumbley said. Pay attention to rustling or light vibrations during night hours, the ants’ most active period. Crumbley suggested recording the sounds or identifying exactly where they are originating. This will be helpful to your pest control operator in identifying the problem. 
• Seeing winged ant species: One of the signs of carpenter ants is that you’ll start seeing large-winged ants indoors. “Carpenter ants swarm in the late spring and early summer each year as part of their mating ritual,” Hodges said. “This is likely a sign of an infestation.”

What’s the best way to get rid of carpenter ants?

Unlike other ant species, such as fire ants and sugar ants, that may be exterminated with DIY methods, permanently removing black carpenter ants is best left to pest control professionals. However, you can take steps to prevent a carpenter ant infestation.

Step 1: Take photos or collect samples for pest control pros

Locating nests inside walls or in beams can be tricky. As is distinguishing carpenter worker ants from other ant species that are entering your house to forage. “Sufficient samples of both the insects and the debris from wooden structures or landscape trees should be brought to a specialist for identification,” said Tracy Ellis, Ph.D., an entomologist at FarmSense, a digital monitoring system that alerts growers about pests, in Riverside, California. 

Gathering evidence will help a certified entomologist at a pest control company to correctly identify the insect and create a proper treatment plan for ant bait.

Be careful collecting specimens. Even though carpenter ants don’t have stingers, they do have strong jaws and can bite you. “They also use a defensive spray of formic acid that can further irritate the skin,” Ellis added.

Step 2: Check your water source and address leaks

“The most effective way to eliminate carpenter ants from your home is to address the source of water intrusion causing rot or decay,” Hodges said. “This can be as simple as caulking the entry points, allowing sufficient time for the affected areas to dry completely, prompting the ants to relocate to a more suitable nesting site.” 

Examine the areas below to keep carpenter ants under control. Signs of leaks and unwanted moisture make a hospitable environment for carpenter ant nests. 

• Attics
• Appliances (around dishwasher and refrigerator)
• Basements
• Crawl spaces
• Exterior wood structures (fence posts, patio and mailbox)
• Plumbing 

Even if you use a professional service, failure to address the root cause of decaying wood may only yield temporary results as a new parent colony might move in down the line. “Repairing the damaged areas and eliminating the source of moisture will ensure long-term results and maintain the structural integrity of the home,” Hodges said.

Step 3: Try boric acid and borax

You may have heard about boric acid and borax in the realm of pest management. “Boric acid is a tried-and-true product for insect control. When used properly, it can be effective in controlling carpenter ants. Knowing where and how to apply boric acid will determine whether it is effective,” Hodges said. “From a DIY perspective, it is not always effective due to a lack of knowledge on how and where to apply it,” he continued, noting it is often overapplied, and carpenter ants simply avoid it. 

If you’re really keen on going the DIY route, Hodges stresses that precision in placement is key. “Many homeowners place boric acid in large mounds or create borders around baseboards with it, applying it directly from the container,” he said. “For proper application, a duster should be used with a tip that allows application into voids and under baseboards. Light application is all that is necessary.”

Also worth noting: “Other dust, like diatomaceous earth, share similarities with boric acid and are equally effective,” Hodges continued. “As with most products, if you apply it in the right place, at the right amount, it will be effective.”

Step 4: Cut tree branches away from the house

Since dead or dying limbs may also be a nesting site for carpenter ants, you may want to hire an arborist to help with tree maintenance. Removing overhanging branches prevents ants from forming a freeway to your home. Additionally, trimming reduces shade and provides air circulation to the house, preventing dampness that could lead to rot and decay. 

“The objective is to protect structures with any wood elements from chronic moisture exposure and remove potential harborages in proximity to the structure,” Ellis said.

Step 5: Don’t go all in on DIY spot treatment 

You can’t just spray any repellent for carpenter ant control. “Spot treatment for ants may trigger a defensive mechanism, causing them to bud and establish multiple nesting sites within the structure,” Hodges warned “It is essential to have an inspection conducted by a pest management professional to determine the extent of the infestation and probable nest locations. Plus, pest management professionals may know effective bait treatments to address your ant infestation, which can be less intrusive than drilling or injecting materials into your walls.”

A DIY approach may miss nest locations, making the treatment either useless or overwhelming. “It is not uncommon to locate several nests in a single home,” Sansig said. Professional pest companies can localize crevices and implement specialized treatment tools such as dusters, insecticides and aerosolized pesticides. They may also use drills and moisture meters to tackle carpenter ant problems better. 

“If ants are nesting away from the home, residual sprays can help to prevent entry and provide some level of control,” Sansig added. “Foundation sprays may not address the main nest in a nearby tree and may only delay future incursions.”

What causes a carpenter ant infestation?

Carpenter ants eat other insects and honeydew, not wood, so it’s not as if they’re noshing on your ceiling beams but rather setting up shop within them. 

To better understand what makes your home attractive to a carpenter ant colony, we asked Ellis what to look for. 

• Rotting wood: Moist, exposed and untreated wood — especially decaying wood softened by fungus — is attractive to carpenter ants because the pest species of carpenter ants have evolved the behavior of using dead trunks, stumps, and rotting trees and logs to make nest shelters, Ellis explained. (Not all species of carpenter ants pose trouble to human-made structures.)
• Leaky plumbing or roofs: “Roof leaks, plumbing leaks, improper ventilation of crawl spaces, and faulty flashing around doors and windows are all common causes of water damage, and thus, common conditions conducive to carpenter ant infestations,” Hodges said. This is a corollary to the rotting wood situation described above
• Swarming season: When it’s time to establish a new colony, carpenter ants swarm to find mates. Swarms are the ants’ way of settling new colonies, Ellis explained, so the ants you see in a swarm near your house could feasibly enter your house. 

Can you get rid of carpenter ants permanently?

Destroying a colony of active carpenter ants burrowing in your home may not halt the threat of them reinvading your home indefinitely. “When carpenter ants establish a population around a structure, eliminating all threats of intrusion may not be feasible,” Hodges said. 

The key to long-term carpenter ant control is monitoring the environment both inside and outside. You’ll want to ensure that your house does not have areas that harbor moisture — this can be leaks or poorly sealed crevices on the outside of your home that allow water to penetrate. Check the area around your gutters and downspouts. 

You’ll also want to trim tree branches that may be touching your house. This stops the carpenter ants from using it as a bridge with a scent trail. Pay attention to your landscaping as well. Old logs, tree stumps and other decaying wood can attract new colonies. 

What’s next?

It can take years for carpenter ant colonies to be established — meaning you must look for telltale signs like wood powder or debris around wooden structures within your house. In addition to burrowing into wall supports, these insects can be found in laths, ceiling joists and hollow floors. Pay attention to water damage outside as well, especially around downspouts, gutter braces and roof panels.

“If you see large black ants around your home, do not wait to seek the consultation of a reputable pest control company,” Sansig said. “They will be able to confirm the species present, identify areas with visible damage and provide a treatment plan tailored to your individual pest need.”

Even after you treat a carpenter ant infestation, monitor the area treated. You may want to call a construction contractor to ensure there is no structural damage or an active water source that can lead to decaying wood. 

Call a pest control company to schedule a consultation.

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