Carpenter Ants

Mature carpenter ant nests will contain about 3000 ants and can occupy a very large area.

Carpenter ants are wood infesting ants and can occur in almost any part of a home including interior and exterior walls, attics, ceilings, sub floors, under shingles, beams, logs, below doors, insulation, and a variety of odd places including the linings of fridges. Carpenter ants vary in size from small workers at 5mm up to the large queens at 17mm. They are either all black or black with a reddish mid – section. A mature nest will contain about 3000 ants and can occupy an area stretching from the floor to the ceiling and be several feet wide. Unlike termites, carpenter ants do not eat wood. They chew galleries in the wood to build their nests. Damp or partially rotted wood is preferred as it is softer and easier for the ants to chew as well as providing a moisture source. They can be found in insulation and Styrofoam such as is found in cathedral ceilings or basement walls. Food in the home is not as attractive to them. Their primary food source being other insects and plant saps. Once the weather is warm enough, they will forage outside bringing the food back into their nest in the house. We have often found carpenter ants tending aphids on trees and shrubs. Watch out for peonies in your garden! Many of the homes we have inspected for carpenter ant problems had peonies planted up against the foundations. In these cases, we recommend that they be moved to beds further out in the yard. Carpenter ants travel long distances, often up to 300 feet from the nest.

Carpenter ants can enter structures in a number of ways. A single queen can enter the home and begin laying eggs. An entire colony can move in using telephone or hydro lines, fences, tree limbs touching the house or simply march across the lawn and up the side of the house. Another way is through firewood. Carpenter ants become dormant in the winter. If infested wood is brought in, the dormant ants can revive when the wood warms up, and possibly move into the structure of the house. Stumps, dead limbs, rotting decks, fences, railway ties and firewood are some common sources in the yard. Eliminating carpenter ants involves finding the nest. Watching for areas of heavy activity, observing where the ants go in and out of the woodwork, listening for noises made by the colony, looking for sawdust piles and watching for activity on the exterior are all ways of trying to determine the nest location. Check for areas that may have a moisture problem such as leaks around tubs or showers, leaking plumbing, roof leaks, leaks around windows, etc.

Carpenter ants are mainly nocturnal and activity peaks during the night. They are most actiVe in warm, humid weather and less active when it is cool. All ants produce a winged stage at a certain time of the year. These are the reproductive stage or Kings and Queens. Carpenter ant reproductives emerge in late spring or early summer. This stage is only produced in well established colonies. It is possible to have more than one nest especially if the ants have been there for a long time. We have inspected homes with multiple nests scattered throughout the house. Prevention of carpenter ants involves eliminating moisture problems, pruning back tree limbs touching the house, removing rotting wood from decks, fences, tree stumps or other sources such as railway ties and firewood close to the house. Treatment of these ants often involves drilling small holes into the nest area and injecting insecticide into the nest. In some cases it may be necessary to pull off trim or paneling to get to the colony. Treating around the outside perimeter will also help.

Although carpenter ants can severely damage a section of wood such as a window sill, beam or stud, especially if it has been water damaged, they will not cause the house to come crashing down around you. Their damage is usually confined to relatively small areas. Well established colonies however can be a major annoyance with large numbers of ants roaming through the house each spring and early summer.