Share this

I should be a large image.

Carpenter Ants

Camponotus spp.
Updated Jul 03, 2022
 
1

Make a Positive Identification

Species: Carpenter Ants
Two carpenter ants

Carpenter ants are 1/4 to 5/8 of an inch long. They are either black, red, or a combination of these two colors.

Species: Carpenter Ants
Carpenter ant with white box highlighting narrow waist

David Cappaert, Bugwood.org

Carpenter ants have a distinctive narrow area between their abdomen and thorax. This area is highlighted by the white box in the photo.

Species: Carpenter Ants
Outdoor wood in landscape with carpenter ant wood dust piles

Edward H. Holsten, USDA Forest Service, Bugwood.org

Carpenter ants damage wood as they build their nests. A tell-tale sign of carpenter ant activity is sawdust piles such as the ones shown in the photo.

Species: Carpenter Ants
Carpenter ants and wood damage

John C. French Sr., Retired, Universities: Auburn, GA, Clemson and U of MO, Bugwood.org

Carpenter ants don’t eat wood; rather, they excavate cavities in wood to support their nests.

Free help Identifying Weeds, Insects & Pests
Get expert pest management info & advice online from OSU's Ask Extension.
Get Help
LOOK-ALIKES: HOUSEHOLD ANTS AND TERMITES
Species: Household Ants
Ants on kitchen counter

Petri Oeschger, iStock

Household ants enter buildings in search of food and moisture or to escape extreme weather or flooded conditions.

Different risks or methods
  • Watch for foraging ants. Wipe them up with soapy water and a sponge. Get rid of them before they go back to the nest.
  • Ant-bait products effectively kill ants when used according to the label instructions.
How to Get Rid of Household Ants
Species: Termites
Subterranean termites on damaged wood

Termites become a problem when they feed and live in our homes and buildings. They cause significant damage to wooden structures. The photo shows subterranean termites on damaged wood.

Different risks or methods

Getting rid of termites in your structure requires good building maintenance practices. You must eliminate water damage and seal entry points. Then treat the affected area and remove the colony.

We recommend hiring a licensed pest control company to control termites in your structures. See How to Hire A Pest Control Company for details.

How to Get Rid of Termites
Free help Identifying Weeds, Insects & Pests
Get expert pest management info & advice online from OSU's Ask Extension.
Get Help
 
2

Carpenter Ants Benefits

  • Carpenter ants have a vital role in forest ecosystems.
  • They recycle dead wood stumps and logs.
  • Carpenter ants are a food source for birds and mammals.
 

Carpenter Ants Risks

  • Carpenter ants become a problem when they enter our dwellings. They cause significant damage to wooden structures.
  • They build nests in crawl spaces, attics, and walls. They use dry wood, water-damaged wood, and insulation to build their nests.
Risk Card
Does it cause harm?
Adults & Children
None
Property
High
Pets
None
Annoyance
High
Environment
Helpful
Action Highly Recommended
 
3

Take Action

Carpenter ants damage wooden structures. Take steps to repair damage and control carpenter ants for homes and structures. Tolerate carpenter ant nests away from structures.

Do I need to take action?
Yes. Take action when carpenter ants are in your home and structures. We recommend hiring a professional pest control service to get rid of carpenter ants or any wood-destroying insect.

What if I do nothing?
Carpenter ant infestations in homes and structures will lead to more damage. The longer you wait to act, the more expensive it will be to repair damage and control carpenter ants.

 
4

Prevent Carpenter Ants

Firewood stack with insect damage

N_Saroach, iStock

Remove Firewood and Wood Debris Piles
  • Wood piles are common carpenter-ant nest locations. Keep firewood and lumber away from your buildings.
  • Remove rotting stumps and wood piles from your yard.
Worker performing inspection in crawl space

SLRadcliffe, iStock

Inspect Your Home and Structures

  • Perform regular inspections of your structures, including the crawl space and attic.
  • Look for signs of water damage and carpenter ant activity (sawdust piles).

 

 
5
Solutions for Carpenter Ants

Controlling carpenter ants in your structure is best left to professional pest controllers. See How to Hire A Pest Control Company for details.

Work with the pest control professional to determine a plan that includes the following actions:

  • Perform a thorough inspection.
  • Fix leaks and eliminate damp areas.
  • Repair and replace damaged wood. Make sure wood does not contact soil.
  • Seal exterior openings that allow carpenter ants entry into your structure.
  • Remove firewood and wood debris piles that attract carpenter ants.
  • Remove carpenter-ant workers and eliminate the colony.
  • Follow up to make sure the control activities worked.

NEED HELP?

Consider a licensed pest control company. Learn How to Hire a Pest Control Company.
Your local Extension Specialist in Oregon  and other states  can suggest other methods.

Jump to

Method Does it work? Is it safe? Recommendation
A
Inspect, Repair & Seal Structure
Very effective
Low risk
Recommended
B
Insecticides from Licensed Pest Control Companies
Very effective
Moderate risk
Recommended
C
Insecticides from Stores
Somewhat effective
Moderate risk
Use if Necessary
D
If Using Insecticides, Protect Yourself & Minimize Risks
 
A

Inspect, Repair & Seal Structure

Non-Chemical Method

Scott Bauer, USDA Agricultural Research Service, Bugwood.org

Inspect, Repair & Seal Structure

Recommended

Getting rid of carpenter ants in your structures requires good building maintenance practices. You must eliminate water damage and seal entry points. Then treat the affected area and remove the colony.

Does it work?
Very effective

These steps are necessary for successful carpenter ant control. Use preventive measures for best results.
How much effort?
High effort

These methods require significant effort.
What's the risk?
Low risk
Possible risk of exposure or harm from chemicals
NONE
  • Thoroughly inspect the interior, exterior, crawl space, and attic of your structure. Look for carpenter ant damage and signs of activity.
  • Fix leaks and eliminate damp areas.
  • Repair and replace damaged wood.
  • Seal exterior openings.
  • Remove firewood and wood debris piles.
  • Remove carpenter-ant workers and eliminate the colony.
Worker inspecting exterior building foundation

fstop123, IStock

Consider hiring a pest control professional to inspect your home for carpenter-ant damage and signs of activity.

Sawdust from carpenter ants

Carpenter ants leave piles of sawdust outside of their nests.

Carpenter ant damage in structure

Mohammed El Damir, Bugwood.org

  • The photo shows carpenter ant damage to wood in a structure. Carpenter ant activity is also visible in the insulation.
  • Remove damaged insulation and repair damage wood.
Leaking faucet on wall with water damage

5./15 WEST, iStock

  • Carpenter ants prefer wet wood for feeding. Remove sources of water.
  • Eliminate plumbing leaks (shown in photo), poor drainage problems, clogged rain gutters, and leaky roofs.
  • Increase ventilation to eliminate damp areas beneath buildings and in attics.
Worker inspecting insect-damaged window frame

Scott Bauer, USDA Agricultural Research Service, Bugwood.org

  • Carpenter ants cause significant damage to wooden structures.
  • The window in the photo needs to be removed and the damaged wood replaced.
Worker replacing damaged wood on outdoor railing

Trigem777, iStock

  • The photo shows a worker repairing a porch roof support post that was damaged by insects.
  • Carpenter ants get inside and build nests in wood. Use treated wood to protect posts and other outdoor wood.
Exterior caulk seals gap between concrete pad and brick wall

StepPro, iStock

  • Seal gaps to prevent carpenter ants entry to your structure. Repair exterior surfaces.
  • Carpenter ants use damaged exterior surfaces to enter structures. Find these entry points, then seal and repair them.
 
B

Insecticides from Licensed Pest Control Companies

Non-Chemical Method

AndreyPopov, iStock

Insecticides from Licensed Pest Control Companies

Recommended

We recommend hiring a pest control company to remove carpenter ant colonies from your home.

Does it work?
Very effective

Insecticides available to licensed pest control companies effectively kill carpenter ants.
How much effort?
High effort

Pest control companies treat your foundation and nearby soil with insecticides. Or they use baits to get rid of carpenter-ant nests.
What's the risk?
Moderate risk

Licensed pest control companies have methods to minimize risk to you, your family, and the environment. Follow their instructions.
Possible risk of exposure or harm from chemicals
El uso de insecticidas conlleva cierto grado de riesgo. El riesgo más bajo se presenta con el uso de métodos alternativos.

You may be exposed to an insecticide if you:

  • Get it on your skin
  • Breathe it in
  • Eat or smoke afterward without washing hands
  • Touch or eat plants that are wet with spray (you, pets, or children)
  • Bring it inside on your shoes or clothes

Follow directions closely to reduce risk.

Pest control companies treat your foundation and nearby soil with insecticides. Or they use bait to get rid of carpenter ant colonies. The most effective insecticides for carpenter ants aren’t available at retail stores. They require a pesticide applicator’s license to use.

Pest control professional with personal protective equipment with clipboard in front of house

mladenbalinovac, iStock

Pest control companies have access to effective insecticides to kill carpenter ant colonies. They also have training to avoid property damage.

 
C

Insecticides from Stores

Chemical Method: Use with caution

Weston Miller, Oregon State University

Insecticides from Stores

Use if Necessary

The insecticides available at retail stores are effective for prevention and control of small or early carpenter-ant infestations.

Does it work?
Somewhat effective

More effective insecticide options are offered by licensed pesticide applicators.
How much effort?
High effort
What's the risk?
Moderate risk

Insecticides come with real risks. ALWAYS read the entire label front to back. Review instructions even for brands you know.
Possible risk of exposure or harm from chemicals
El uso de insecticidas conlleva cierto grado de riesgo. El riesgo más bajo se presenta con el uso de métodos alternativos.

You may be exposed to an insecticide if you:

  • Get it on your skin
  • Breathe it in
  • Eat or smoke afterward without washing hands
  • Touch or eat plants that are wet with spray (you, pets, or children)
  • Bring it inside on your shoes or clothes

Follow directions closely to reduce risk.
Ant bait package

Weston Miller, Oregon State University

Ant Baits

  • Find products that specifically mention carpenter ants.
  • Ant baits include a food source and insecticide(s).
  • Foraging ants take the bait back to the nest. The ants transfer the bait among workers, larvae, and queens.
  • It takes several weeks for the bait to kill the entire colony of ants.
  • Carpenter ants’ food preferences are complicated. They may not be attracted to ant-bait food sources. Success may vary.
  • Follow the product label instructions to minimize the risks and maximize the benefits.
Photo of insecticide label that highlights interior and exterior use

Weston Miller, Oregon State University

Ant Sprays

  • The white box on the example label has a picture of a carpenter ant and other wood-destroying insects.
  • The other white box on the label states “For indoor & outdoor use.” The product label recommends the product be applied to gaps in damaged wood and cracks and crevices of wooden structures.
  • For carpenter ants, the product kills workers that live or feed in the treated area.
  • The product is not recommended as the only carpenter-ant control action.

 

 

If Using Insecticides, Protect Yourself & Minimize Risks

Chemical Method: Use with Caution
Family playing on kitchen floor

staticnak1983, iStock

Why Is It Important to Read Insecticide Labels?

  • They have detailed information on how to use the product correctly and legally.
  • The labels contain information on potential hazards of the product.
  • They provide instructions you should follow for poisonings and spills.

Key Safety Tips for Insecticides

  • Read the entire label front to back. Follow the instructions.
  • Review the instructions even for brands you know.
  • Only apply the product where the label says it may be applied.

The Label is the Law

ALWAYS read the label before using insecticide products. The label is a legal document that provides information on how to safely use the insecticide. This helps avoid harm to human health and the environment. Using an insecticide in off-label ways is illegal. It can result in legal enforcement actions.

READ THE LABEL & Follow Instructions
It has instructions to protect you and the environment.

  • Labels are different for every product and they often change over time.
  • Use a magnifying glass for small print.
  • Pay attention to CAUTION, WARNING, and DANGER statements.
  • Pay attention to the PRECAUTIONARY STATEMENTS.
  • The law states you must read and follow insecticide instructions.

Protect Yourself
Eye, skin & lung irritants

  • Wear gloves, safety glasses, a long-sleeve shirt, pants, socks, and shoes.
  • Avoid contact with eyes, skin, or clothing.
  • Wash hands after mixing or applying, and before eating or smoking.

Protect Children & Pets
Keep out of the reach of children.

  • Keep children and pets away from the application area.
  • Remove toys and pet dishes from the area before applying insecticides. Wait until spray has dried or dust has settled.

Avoid Wet Weather & Keep Insecticides Out of Waterways
Some insecticides are toxic to fish and aquatic invertebrates.

  • Don’t spray insecticides in water.
  • Insecticides sprayed on the exterior of your home can wash off with rain and enter waterways.

Storage & Disposal

  • Store out of the reach of children and pets.
  • Store in a cool and dry place.
  • Never pour down any drain.
  • If you mix too much, apply it rather than storing it.
  • Don’t put pesticide containers in the trash unless instructed by the label.
  • Take unused insecticides to a hazardous waste facility.

Call  1-800-CLEANUP (1-800-253-2687) to find out where to dispose of pesticides.

For the Portland metro region in Oregon, contact Metro’s Recycling Information. Call  503-234-3000, email   or visit Metro’s website  

More about:

About Using Pesticides on School Grounds in Oregon

If using pesticides on school grounds, there are special rules in Oregon. See School Integrated Pest Management  (Oregon Department of Agriculture).

NEED HELP?

The National Pesticide Information Center (NPIC)  can answer questions about pest control chemicals.
 1-800-858-7378 or npic@ace.orst.edu  

Consider using a licensed pest or weed control company. Learn How to Hire a Pest Control Company.

Your local Extension Specialist in Oregon  and other states  can suggest other methods.

 

Hire a Professional

Hire a professional pest control company to advise and help you solve carpenter ant problems. They have the expertise and tools to get the job done right and minimize risks to your home and family.

See How to Hire a Pest Control Company for details.

Pest control worker

AndreyPopov, iStock

SEE OTHER COMMON PACIFIC NORTHWEST INSECTS

Content provided by editor Weston Miller and writer J. Jeremiah Mann. Pesticide safety information edited by Kaci Buhl.

 Reviewed by OSU Department of Horticulture.

Photo of Weston Miller

Weston Miller

Project Founder and Content Writer

Weston Miller served as Community and Urban Horticulture faculty for Oregon State University Extension Service for Clackamas, Multnomah, and Washington Counties. Weston is an author for content for this website. He developed funding partnerships with Portland area agencies to initiate and build out the Solve Pest Problems website focused on this goals:

J. Jeremiah Mann

J. Jeremiah Mann

J. Jeremiah Mann completed a Physical Science undergraduate degree at Humboldt State University, and M.S, Ph.D focusing on plant science topics at UC Davis. He went on to work for the Natural Resources Conservation Service and in a leadership position serving a private agricultural technology company. He currently lives in Sacramento California where he consults on pest and property management topics.

Photo of Kaci Buhl

Kaci Buhl

At the state level, I lead the Pesticide Safety Education Program (PSEP). The program hosts live recertification events around the state, serving over 1,000 licensed pesticide applicators each year. We also produce web-based training modules and license-preparation study manuals. Special training for unlicensed pesticide applicators is also available through a grant from the USDA Specialty Crop Block Grant Program. The PSEP at OSU works closely with the Oregon Department of Agriculture's Pesticides Division.

CARPENTER ANT REFERENCES

Carpenter Ants  
University of California IPM Carpenter Ants

Carpenter Ants  
National Pesticide Information Center

Wood-infesting Insect Pests: Ants  
Pacific Northwest Insect Management Handbook