Carpenter ants are one of many household pests capable of damaging wooden structures and while they usually are not the primary cause of wood damage, they can infest a damaged area and significantly worsen it over time. Knowing what signs to look for will make it much easier to locate and deal with an ant infestation before it can cause further damage.
Carpenter ants destroy wood in order to create a site for their colonisation, so they prefer areas of wood that have already been weakened by water. This rotten wood is much easier for them to hollow out and colonise. For this reason it is best to start searching for signs of ant infestation with areas that are more prone to water damage, such as structures near plumbing fixtures in bathrooms or the kitchen.
The first sign of an ant infestation will be the presence of numerous worker ants moving visibly through the house. These worker ants will be most active at night and the greater the number, the more likely it is that there is a nest nearby. However, since worker ants will travel long distances from the nest in order to acquire food, the presence of worker ants in the house is not a guarantee that there is a nest nearby.
A clear sign of a more advanced ant infestation is the presence of small piles of sawdust under or near small, slit-like openings in a wooden structure. When the ants hollow out a piece of wood to make room for their colony, they will dispose of the debris outside of the nest location in small piles. Often times small dead ant body parts can be found mixed in with the sawdust.
If the sight of a possible ant nest is known, faint rustling sounds can be heard from inside the wood. Since this can be hard to hear on its own, you can use a screwdriver to tap on the wood where the rustling is the loudest to alarm the ants and heighten their activity, making the rustling louder. A stethoscope can also help you hear a potential nest.
If there is an ant infestation, this will be clear in the springtime and early summer with the presence of larger, winged ants. These can most easily be found along window sills, door jambs and in the webs of spiders. Unlike the wingless worker ants, these flying ants will be relatively close to their nest, so if they are found within the house, it is a guarantee that there is an infestation.