Because carpenter ants enter buildings, they are considered to be the most destructive common insect pest we have in Canada. Two common species are found, one is all black, the other is black with a rusty red mid section. They vary in size from one quarter inch to three quarters of an inch.
Carpenter ants can do considerable damage to wood structures. Initially, they establish a nest in decaying wood but, once established, they tunnel into good wood.
These ants usually have a parent colony in outdoor nests, typically living in dead trees, logs, stumps, firewood, or landscaping wood. Once the colony becomes larger it can expand into satellite colonies often in nearby warm buildings.
Many homes on the West Coast are adjacent to forested areas or clumps of trees such that there are well established ant colonies nearby which can attack these homes. Carpenter ants excavate in structural beams and wall studs, and can cause considerable damage to a dwelling, although not as serious as that done by termites.
Carpenter ants establish nests in both dry and moist wood, but prefer moist. Therefore, nests are most likely to be found in water damaged wood around sinks, bathtubs, window and door frames, roof leaks, and so on. Hollow moist spots in wall voids are common nest spots.
Killing only the visible ants does not cure the problem, as only 10% of the ants leave their nests in the dwelling. These hidden nests must be located and destroyed by professionals.