If your home has been infested by carpenter ants, you probably already know how hard it can be to eradicate them. Because carpenter ants usually have a parent nest outside the house and satellite nests within, they have to be combatted on both fronts. Whether you call in a professional or do it yourself, the best way to get rid of carpenter ants is to find their nests and destroy them.
If the nests are inside, you'll probably be able to hear their rustling and tapping noises from inside the walls. Piles of shredded-looking sawdust are also an indication. But your best way to find a parent nest is to follow ants when they have other insects in their jaws; they are returning to feed larvae. Remove and destroy the parent nest physically. Do not use toxic products if this is an outside nest; the pesticides can leach into groundwater. Control colonies within your home with boric acid dust--the ants walk through it and then contaminate the colony. You can also kill carpenter ants with a perimeter spray containing pyrethroids or permethrin applied around the outside of your house.
Use your vacuum cleaner to scoop up stray carpenter ants--the heat of the bag will kill them. Avoid spraying these foraging ants with poison; all that will accomplish is to make them scatter their satellite nests and make them harder to find.
To further control carpenter ants, replace any decaying or infested wood. Store all firewood outside the house and off the ground. Keep food in sealed containers, and sweep up crumbs. Address humidity problems in the home; carpenter ants build nests in damp wood. You can also use diatomaceous earth around the perimeter of the home to discourage insects from entering, but this must be repeated every few weeks in the spring, summer and fall.