Carpenter ants are wood-destroying insects. They are so-named because they excavate wood in order to build their nests. Carpenter ants are common in the northeast and nest outdoors in damp, decaying wood like tree stumps, logs or hollowed out trees. As such, homes that are either in wooded areas or have many trees on the property are particularly susceptible to carpenter ant infestations. Occasionally, carpenter ants build their nest inside a home, seeking out water-damaged, decaying wood that they can easily excavate. In doing so, they can seriously damage the structure of the home.
Understanding carpenter ant habits is necessary to locate and eliminate any nests, which is essential for long-term control of the infestation.
Carpenter ants are large ants, ranging in size from ¼ to ½ inch in length; most typically, adult carpenter ants will fall into the ½ inch size. They are usually black; however, they can also be red or brown. Carpenter ants are social insects that live in colonies that can exceed more than 10,000 workers. In large colonies, it is common for the parent colony to establish multiple satellite nests in nearby indoor and outdoor sites.
At times, a carpenter ant problem is first identified not because homeowners see the ants themselves, but because they notice damage to their home. During a renovation or home improvement project, a carpenter ant infestation is revealed by hollowed out “galleries” of wood somewhere in the home. Their excavation results in smooth tunnels inside the wood. Unlike termites, carpenter ants do not eat wood; rather, they excavate it for their nests. Beyond seeing the hollowed out galleries, homeowners may notice sawdust piles in areas where carpenter ants have built nests. These piles are usually an indicator of a severe infestation.
Homeowners may also notice carpenter ant activity is outdoors. Carpenter ants are often found in trees or tree stumps, rotting wood, firewood piles, fence posts or other wood, particularly if it is untreated. Carpenter ants are attracted to wet wood since it is easy to excavate. A common source of an indoor carpenter ant infestation is wood or trees outside. Worker carpenter ants will forage indoors in search of a moisture and food source.
While there is carpenter ant activity thoughout the year, spring is a common period of high activity, particularly inside a home. Spring is typically a wet season and carpenter ants prefer moist conditions. However, foraging carpenter ants can appear any time of the year.
Because carpenter ants are attracted to moisture sources, when inside a home, they are commonly found in the kitchen and bathroom areas. Homeowners may notice them near a leaky pipe, leaky roof, damaged window and doorframes, crawl spaces under roofs, chimneys, sinks, showers and bathtubs or other water sources inside of a home.
Carpenter ants usually gain access to buildings through cracks around doors and windows, holes for wires, or inside of wet, damaged wood. They will also crawl along overhead wires, shrubs, or tree limbs that touch the building far above the ground. Although carpenter ants first invade wet, decayed wood, they may eventually infest dry, undamaged wood.
Moisture attracts carpenter ants into your home. Therefore, the key to carpenter ant control is moisture control. Eliminating sources of water and removing wet, rotting wood will reduce the likelihood of a carpenter ant infestation. Therefore, homeowners should promptly fix plumbing leaks and fill any gaps or cracks on the outside of the home with silicone caulk. If a basement, crawl space or attic is damp, installing a commercial grade dehumidifier will dramatically reduce insect-attracting moisture and inhibit dangerous mold growth.
Overgrown landscaping, improperly stored firewood, and untreated wood outdoors can also invite a carpenter ant infestation. Trim trees, particularly those close to the house. Limbs that extend to the roofline or shrubs that grow too near a home can act as a highway for carpenter ants to enter your home. Hollowed out or water damaged trees should be removed and the stumps ground down. Firewood and other wood-building materials should be stored at least 20 feet from your home and at least five inches off of the ground.
For long-term control, the nest and queen must be located and eliminated. It is possible for there to be one main nest located outdoors with smaller satellite nests located indoors. The nest is made up of one queen that does the egg laying and thousands of worker ants, each one having a specific function such as foraging for food, guarding the nest, or excavating wood. Once the nests are removed, the damaged wood and any moisture sources must be eliminated to reduce the risk of a future infestation.