The Wood Carpenter Ants Like Best

Carpenter ants are strongly attracted to moist, softened or decaying wood. They prefer to tunnel where fungi or long-term dampness have already started to break down wood fibers. In houses and outbuildings, this often means:

• Leaky window and door frames.
• Rotten deck posts, rails and stair stringers.
• Wet sill plates, mudsills and rim joists in poorly drained basements or crawl spaces.
• Roof leaks around chimneys, skylights and eaves.
• Water-damaged siding and trim boards.

Softwoods like white pine, spruce and western red cedar are common targets because they are relatively easy to excavate once they become damp. However, carpenter ants will also move into hardwoods such as oak and maple if those boards stay wet in a humid climate or sit in direct contact with soil.

It’s the moisture content and accessibility of the wood—not just the species—that determine where carpenter ants will nest. A dry spruce joist in a well-ventilated attic is far less attractive than a moist piece of oak that sits against a foundation wall with chronic condensation problems.

Carpenter Ants vs. Termites: What’s the Difference?

Homeowners often confuse carpenter ants with termites because both attack wood. The differences are important:

• Diet: Termites eat cellulose and digest the wood they tunnel through. Carpenter ants do not eat wood; they remove it to make smooth galleries and nests.
• Tunnel appearance: Carpenter ant galleries are clean, smooth and sanded-looking, with wood shavings and insect parts (frass) pushed out. Termite tunnels are packed with mud and soil.
• Frass: Carpenter ants leave piles of sawdust-like frass below their tunnels. Termites do not create these piles in the same way.

Correctly identifying whether you have carpenter ants or termites determines the best treatment strategy and helps you work effectively with a local pest management professional.

Natural Habitats of Carpenter Ants

In the wild, carpenter ants are an important part of forest ecosystems. They commonly nest in:

• Dead or dying tree trunks and branches.
• Rotting stumps and fallen logs on the forest floor.
• Hollow sections of live trees weakened by disease or decay.

In these settings, they help break down dead wood and recycle nutrients back into the soil. Their tunneling work opens pathways for fungi, bacteria and other decomposers that complete the decay process. The problem arises when this same nesting behavior shifts from forest trees to wood-frame houses, garages and sheds. Any place where wood stays damp—and especially where it contacts soil—is a potential invitation.

Found Worldwide

Carpenter ants are found on almost every continent, with different species adapted to local climates and forest types. They are especially abundant in temperate regions where mixed conifer–hardwood forests provide plenty of fallen logs and dead branches. However, many species also thrive in subarctic climates, high-elevation forests and even tropical mountains.

Around homes, carpenter ants are most common in areas with:

• High annual rainfall or long, damp seasons.
• Older wood-frame construction with minimal flashing and moisture protection.
• Dense vegetation and stacked firewood near exterior walls.

Knowing which carpenter ant species live in your region—and how they behave—can help you and your pest professional design more targeted carpenter ant control and prevention plans.

Life Cycle and Caste System

Like other ants, carpenter ants go through a complete metamorphosis with four stages: egg, larva, pupa and adult. The queen lays eggs that hatch into legless larvae. These larvae are fed and groomed by worker ants until they pupate and eventually emerge as adults. Depending on colony needs, new adults develop into:

• Worker ants – sterile females that excavate wood, care for brood and forage for food.
• Soldiers – larger workers with strong mandibles that defend the nest.
• Reproductive males and females – winged ants that participate in mating flights.

This caste system allows carpenter ant colonies to grow into complex, resilient societies that can persist for years if undisturbed.

Reproduction and Colony Formation

Carpenter ant colonies begin when a single mated queen finds a protected crevice—often in a damp piece of wood, under bark, or inside a wall void—and starts excavating small chambers. She lays a modest batch of eggs and tends them herself until the first workers hatch. From that point on, the queen focuses on reproduction while her daughters handle excavation, foraging and brood care.

As the colony grows, it may create satellite nests in nearby structural members such as floor joists, wall studs and roof framing. These satellite colonies are connected by hidden tunnels and foraging trails that can extend considerable distances. In a large, long-standing infestation, carpenter ants can undermine the strength of:

• Support posts and beams in basements and crawl spaces.
• Deck framing and porch roofs.
• Wooden steps, landings and railings.
• Framing around chimneys, vents and roof valleys.

This is why professional inspections often include probing or drilling suspect wood to identify hollowed areas that are not visible from the surface.

Foraging and Feeding Habits

Carpenter ants are omnivorous, opportunistic foragers. They travel along concealed routes inside wall voids, under siding and across branches that touch the roof. Outdoors they feed on:

• Honeydew produced by aphids and scale insects on trees and shrubs.
• Plant nectars and overripe fruits.
• Dead insects and other small invertebrates.

Inside homes, carpenter ants readily take advantage of:

• Sugary spills, crumbs and open food containers.
• Pet food dishes left out overnight.
• Grease, meat scraps and kitchen waste.

They establish pheromone-marked foraging trails that allow workers to quickly return to productive food sources. Although they do not eat wood, their presence near moist or damaged wooden structures is a red flag that a nesting site may be nearby.

How Carpenter Ants Damage Your Home

The primary damage from carpenter ants comes from the cumulative excavation of galleries and tunnels within wood. Over time, structural members can become so hollowed out that they lose much of their load-bearing capacity. You may see:

• Floors that sag or feel “spongy” underfoot.
• Window and door frames that shift out of square or stick.
• Porch and deck railings that wobble when leaned on.
• Rooflines that show subtle but progressive sagging.

Because carpenter ants generally work from the inside out, the surface of the wood may still look solid. By the time visible damage appears, the internal structure can already be badly compromised—highlighting the importance of early detection and regular inspection of wooden structures.

Signs of a Carpenter Ant Infestation

Detecting a carpenter ant infestation early is the best way to limit repair costs. Common warning signs include:

• Sawdust-like debris (frass) piling up below beams, baseboards or wall voids.
• Rustling, faint chewing or tapping sounds inside walls or ceilings, especially at night.
• Piles of discarded wings from swarming, winged reproductive ants in spring or early summer.
• Wood that sounds hollow or papery when tapped with a screwdriver handle.
• Trailing ants moving along foundation walls, plumbing lines or tree branches touching the house.

Any combination of these signs—especially in moisture-prone areas like bathrooms, kitchens, basements or under wood decks—should prompt a closer inspection.

Inspection and Detection Methods

A thorough carpenter ant inspection includes:

• Checking around windows, doors and roof penetrations for moisture-damaged trim and siding.
• Inspecting basements and crawl spaces for rotten sill plates, rim joists and support posts.
• Examining decks, stairs, pergolas and fences built from softwoods like pine and spruce.
• Probing suspect wood with an awl or screwdriver to locate soft or hollow sections.
• Following ant trails back to likely nest sites using a flashlight at dusk or dawn.

If you suspect a large or long-standing infestation, it is wise to consult a licensed pest control professional who can use specialized tools—moisture meters, borescopes and targeted treatments—to locate and eliminate hidden nests.

Chemical and Non-Chemical Control Strategies

Much like with termite control, effective carpenter ant management combines chemical and non-chemical (structural) strategies.

Chemical options may include:

• Residual sprays along foraging trails and entry points.
• Non-repellent insecticides that ants carry back to the nest.
• Slow-acting baits placed where ants are actively feeding.

Non-chemical prevention focuses on removing the conditions that invite ants in:

• Fixing roof, plumbing and gutter leaks that keep wood continuously damp.
• Improving drainage and ventilation in basements, crawl spaces and attics.
• Keeping firewood, logs and lumber stacks off the ground and away from exterior walls.
• Trimming trees and shrubs so branches do not touch roofs and siding.
• Sealing gaps around utility lines, vents and foundation cracks with caulk or foam.

An integrated pest management (IPM) approach that combines structural repairs, moisture control and targeted treatments provides the most durable, long-term protection for your home.

Carpenter ants may be small, but their ability to quietly hollow out beams, studs and decks makes them a serious threat to any wood structure. By learning how these insects live, where they nest and what signs to watch for, you can respond quickly and keep your home, cabin or wood-floored interior safe from their hidden tunneling.

Carpenter Ants