Danger Level: 4/5

Carpenter Ants

Camponotus species

Updated May 2026 · Boise, ID

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Quick Facts

Size6-13mm long (largest common ant)

ColorBlack, sometimes with reddish-brown thorax

LifespanWorkers: 7 years, Queens: 25+ years

Active SeasonsSpring, Summer, Fall

Common LocationsWood structures, Trees, Decks

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Identification

How to Identify Carpenter Ants

Quick Answer

Carpenter ants are among the largest ants in North America, measuring 6-13mm long (about a quarter inch). Most around Boise are solid black, though some species in the foothills have a reddish-brown thorax. Look for a single node between the thorax and abdomen, an evenly rounded thorax, bent (elbowed) antennae, and a narrow waist. Those last two features are how you tell them apart from termites.

Carpenter Ants - showing key features for identification

Behavior

Carpenter Ants Behavior & Habits

Understanding how carpenter ants behave helps prevent infestations

Signs You Have Carpenter Ants

What homeowners spot first

Large black ants inside home, especially at night
Sawdust-like debris (frass) near wooden structures
Faint rustling sounds inside walls
Winged ants emerging indoors (spring swarmers)
Damaged wood with smooth, sandpapered galleries
Ants trailing from trees or stumps toward house

Carpenter ants excavate galleries in wood to build nests. They don't actually eat the wood, they remove it to expand the colony. Parent colonies usually sit in trees, stumps, or landscape timbers, with satellite colonies tucked inside walls, decks, and window frames. They're mostly nocturnal, so the big black ants you spot at 11 PM are the same ones quietly chewing through your trim during the day.

Dangers

Carpenter Ants Risks & Dangers

What carpenter ants can do to your health and property

Health Risks

Carpenter ants can bite when handled or pressed against skin, but they rarely go after people unprovoked. They don't carry diseases. The bigger health concern is what their presence usually means: a hidden moisture problem in the wall, sub-floor, or roof line that's also feeding mold and wood rot.

Property Damage

Carpenter ants cause real structural damage by hollowing out wood for nesting. The damage progresses slowly over years, not months like termites, but untreated colonies can compromise framing, deck posts, and window headers. Repair costs in the Treasure Valley typically run $1,000 to $10,000+ depending on how long the colony went unnoticed.

Warning Signs

Signs of Carpenter Ants Infestation

Look for these indicators in your home

Large black ants inside home, especially at night

Sawdust-like debris (frass) near wooden structures

Faint rustling sounds inside walls

Winged ants emerging indoors (spring swarmers)

Damaged wood with smooth, sandpapered galleries

Ants trailing from trees or stumps toward house

Carpenter Ants in Boise & the Treasure Valley

Carpenter ants are one of the most common ant calls we run in the Treasure Valley, especially in the Boise foothills, North End, Hidden Springs, and along the river corridor in Eagle and Garden City. Older 1950s-1970s ranch homes with cedar trim, wood decks, and big mature shade trees are the prime targets. Idaho's dry summers push the colonies toward any moisture source they can find, so we see most carpenter ant activity from late April through October, peaking when irrigation kicks on and crawlspace humidity rises.

Our Solution

How We Eliminate Carpenter Ants

Professional treatment for complete elimination

Carpenter ant control means tracking down both the parent colony (usually outside in a tree or stump) and the satellite colonies hiding in your walls. We combine targeted non-repellent baits the workers carry back to the queen, dust applications inside wall voids, and a full exterior perimeter spray. Full knockdown typically takes 2 to 4 weeks because the colony structure is layered. New customers start at $49 for the initial service, and our free re-service guarantee covers any callbacks between visits if the ants come back.

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Prevention

How to Prevent Carpenter Ants

Steps you can take to reduce the risk of infestation

Eliminate wood-to-soil contact around foundation

Fix all moisture problems and leaky pipes

Replace water-damaged wood promptly

Trim tree branches away from roof

Store firewood away from house and elevated

Ensure proper drainage away from foundation

FAQ

Carpenter Ants Questions Answered

Common questions about identification, prevention, and treatment

Are carpenter ants worse than termites?

Carpenter ants cause damage more slowly than termites, but a colony left alone for two or three years can still compromise framing, deck posts, and window trim. Unlike termites, they don't actually eat wood. They excavate it for nesting, so you'll see sawdust piles rather than mud tubes. Green Guard treats carpenter ants under our standard pest control plans; termites we don't treat and we refer those out.

How do I know if I have carpenter ants or regular ants?

Carpenter ants are much larger than pavement or sugar ants (6-13mm vs. 2-4mm), usually solid black, and you may notice sawdust-like debris (frass) piled near baseboards, window sills, or deck posts. If the ants you see are over a quarter-inch long and walking single file inside the house at night, they're almost always carpenter ants.

Can I treat carpenter ants myself?

Hardware-store sprays rarely wipe out a carpenter ant colony. Spraying visible ants kills the foragers but signals the queen to relocate the satellite colony deeper into the wall, which usually makes the problem worse. Carpenter ants need non-repellent baits the workers carry back to the queen, plus dust applications inside the wall voids you can't reach from the outside. That's why we recommend a professional plan starting at $49.