Carpenter ants are generally described as big black ants and range in size from the ¼” workers to the ¾” queen. They excavate in damp or damaged wood to build their nests. Although they usually invade structures through damp wood they will expand into dry undamaged wood as their colony grows. Their nests are usually found in areas that are vulnerable to moisture such as around and under windows, roof eaves, decks and porches. Main colonies are usually found in stumps, fence posts and other outdoor wood sources below grade as they need a constant water source to survive. But satellite nests will be constructed in structures. Nest can sometimes be located by sawdust like substance known as frass. Carpenter ants only excavate to enlarge their nests, unlike termites, they do not eat wood. But they do cause more damage on average in southern Ontario then termites. Prolonged carpenter ant activity can lead to structural failure over time.