How to Destroy a Carpenter Ant Nest

Updated November 21, 2016

Carpenter ants are small, black ants that range in size from 1/4- to 1/2-inch long. In nature, carpenter ants provide many beneficial environmental services. The ants nest in dead wood and speed up the process of decay, restoring nutrients to the soil and facilitating new plant growth. The small ants can become an unwanted pest in home environments, however, and can cause structural damage to your home as they create nests in wood. Carpenter ants do not eat wood, but rather excavate small holes in order to construct nests. Destroying carpenter ant nests can easily be done with the right approach and proper chemical selection.

Look for carpenter ant activity in your home in the evenings when they are most active. Monitor carpenter ants carefully in your home and note where they are most active.

Place a piece of masking tape on the floor near carpenter ants and place a small dab of honey on the tape. Carpenter ants prefer to feed on sweet foods such as honey and they will take the honey directly back to their nest.

Follow ants that have been feeding on the bait honey back to their nest. Follow the ants patiently since carpenter ants can nest far distances from where they forage for food. The ants will likely enter a concealed location -- through the floorboards, behind a cupboard or windowsill.

Look for signs of carpenter ant activity on the outside of your home where you observed the ants last to determine if the ants are nesting outdoors or in your home. If you do not observe any signs of carpenter ants outside, then they are likely nesting inside your home. If outdoors, follow the ants as best you can to try to locate the nest.

Search for any dead or decaying wood on your property and look for carpenter ants coming or going.

Destroy the nest by soaking it with a insecticide solution containing carbaryl or chlorpyrifos.

Monitor the foundation of your home and look for signs of carpenter ants after applying the insecticide to ensure that you destroyed the nest.

Drill several holes in a row where you suspect the carpenter ants are nesting; holes should be 1/8 inch in diameter and be located at least 3 to 5 feet on either side of where you think the nest is located.

Spray boric acid -- a dust insecticide readily available from most home and garden stores -- into the holes to destroy the nest. Boric acid is an effective contact insecticide that disperses easily and kills carpenter ants quickly.

Monitor the area around the treated area carefully for signs of carpenter ant activity, and re-treat as needed.


Always carefully follow the instructions on insecticides, as labelled.


Take extra caution when treating areas around electrical sockets in your home.

Things You'll Need

  • Masking tape
  • Honey
  • Boric acid
  • Liquid insecticides
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