The best method of carpenter ant control is likely to first locate the carpenter ant nest. Once the nest is located, insecticide can be used to kill the ants. It is usually not possible to control carpenter ants unless the nest is found and destroyed. Using insecticide without finding the nest first might keep the ants at bay for a short time, but they will likely return as soon as the effects of the insecticide wear off. There is always a chance that your methods of carpenter ant control will not be sufficient to take care of the problem, and if this is the case, you might have to call a pest control specialist to deal with the ants.
If you want to locate a carpenter ant nest, you may be able to do so by following the trail your carpenter ants are following. Most ants follow scent trails leading from their nests to food sources. Watching where the ants go will likely get you in the general vicinity of the nest location. If the carpenter ants are inside your home, you may be surprised to find that their nest is actually outside. Carpenter ants can get inside houses through cracks in foundation and siding.
When you find the carpenter ant nest, you can spray or douse it with insecticide designed for killing ants. This should completely take care of your problem unless there is more than one nest close to your residence. If you discover that the nest is inside a wall, carpenter ant control might be slightly more difficult. To deal with ant nests inside walls, you will probably have to drill small holes in your walls and spray some boric acid powder into the holes in the hopes that it will land on the ants. Boric acid can kill ants because the powder contains tiny crystals that stick to insects and dehydrates them.
You may also benefit from preventing more carpenter ants from entering your home. Any cracks in your siding or foundation should be sealed up with caulk, and you may additionally want to trim back any vegetation that is touching your house. If you have piles of wood or yard debris stacked up next to your house, you might want to consider moving it to another location. In the event that your methods of carpenter ant control are ineffective, you may have to call in a pest control expert to help you.