In some areas of the country, carpenter ants cause more damage to structures than termites.  They are difficult insects to control and can cause extensive damage to wood members in a fairly short period of time.  Carpenter ants do not actually eat wood but excavate galleries within it to use as nesting sites.   Foraging activity can occur at any time of day but usually peaks at night.   When foraging inside houses, carpenter ants are attracted to sweets, meat, grease and fat.

A carpenter ant colony is usually formed by a queen who establishes a nest in or around your home.  In mature infestations, there may be as many as ten satellite colonies linked to the parent colony by trails.  There is a frequent exchange of workers between these satellite colonies and the main nest.  Colonies normally do not produce winged reproductive forms until they are at least two to four years old with emergence of the reproductive’s typically occurring from May through July. The female reproductive’s then swarm from the nesting site to establish new nests.

The most common way in which homes become infested is through emigration of an existing colony.  Houses located near wooded areas or brush covered vacant lots are good candidates for infestation.  Carpenter ant colonies are inclined to move if they are disturbed, as often happens during construction or severe weather where nesting sites are disturbed. 

Inspecting For Carpenter Ants

Some Common Signs of Carpenter Ant Infestations:

  • Frass, which is made up of wood shavings, bits of soil, dead ants and parts of insects.  This material is often piled up outside of nest openings and found in spider webs and window sills.
  • Small windows or slit-like openings that carpenter ants cut into infested wood.   These windows are actually “garbage chutes” which are used to dispose of frass or unwanted materials.
  • Alates are the winged reproductive’s that take flight in the spring.   
  • Worker carpenter ants are more active at night, so you may not see any activity during normal working hours.  Even if you do, it does not mean that the nest is nearby.  Worker ants can travel up to 300 feet from their nesting site in search of food.
  • Clicking or rustling sounds can sometimes be heard coming from carpenter ant nests.  If you identify a potential nest site, try tapping against it with a screwdriver.  You may hear a response — the clicking of alarmed ants.
  • Wood damaged by carpenter ants contains galleries that are very clean and smooth.

The first sign of a carpenter ant infestation is usually the sighting of numerous workers throughout the home. Carpenter ant workers tend to roam far and wide looking for food, and some transient workers are sure to enter any home located in a wooded area.  Signs of an active infestation include the presence of fibrous sawdust beneath slit-like openings in wood members and faint, rustling noises in walls and woodwork.  A positive indication that an active, mature infestation is present is the emergence of large winged ants (alates) from walls, ceilings, or crawl spaces.

Carpenter Ants normally excavate wood that has been softened by decay or other insect’s; however, they will tunnel into sound wood when conditions are favorable.   Nests and galleries may be located a considerable distance from the point or points of entry.  In addition to structural lumber, sites such as hollow-core doors, window headers, wall voids, and foam panels are particularly attractive to carpenter ants.

Carpenter ants often enter homes through openings found in foundations, cracks, plumbing holes, cable connections, soffits, entrances for telephone and electric wires, etc.