One myth about Carpenter Ants is that they eat wood. However they do hollow out wood in order to nest. These ants are larger than a regular black ant, although size can vary.
Finding a few carpenter ants in or around your log home is not a sign of infestation. If there are trees around your house, which there usually are, then you probably have carpenter ants in the area. In addition to nesting in wood they will often nest in Styrofoam (EPS) panels and other types of insulation.

If you find numerous foraging ants, especially in your kitchen or bathroom you may have an infestation. A sure sign is the presence of large winged ants in late spring and early summer. Most colonies start outdoors in the cavity of a tree. As the colony grows, satellite colonies can happen in moist wood, foam panels within the house. Once these colonies are established chance of additional satellite colonies grows and infestation increases.

Control and Prevention
Be vigilant in checking for any moist areas in your home. Faulty plumbing or water penetration into log walls, are the most important areas to monitor. Most pesticides only create more problems by causing the ants to spread out and build new colonies. The better way is to treat logs with a borate such as Shell-Guard, Armor Guard or other Borate products.
Carpenter Ant infestation is not an easy fix, and a Log Home Professional in the Log Home industry is your best bet for taking care of this problem.

Source: http://westerloghomerestoration.com/Carpenter%20Ants-2.htm