Carpenter ants don’t consume wood like termites but excavate it to make their nests, which in large colonies can consist of an extensive network of galleries and tunnels often beginning in an area where there is damage from water or wood decay. From here they can expand the nest into sound wood and compromise structural integrity. They also commonly nest in wall voids, hollow doors, and insulation. Infestations can even occur in new buildings when land clearing in the surrounding area disturbs established colonies, causing them to move into the structure.
In natural settings, they excavate into the heartwood of living trees or into dead trees and stumps. These latter infestations play an important role in the decomposition of wood.