Carpenter ants are a bit different than the typical ant in that they wlll nest in wood (tree trunks, firewood piles and at times somewhere in the structure of our homes, etc. The Carpenter ant will first establish the nest in wood that is often times rotten or rotting or in the case of the home, where there has been a structural problem were moisture has entered. Window sills and door sills are examples. They forage for food elsewhere, leaving the nest to do so. If these are in a structure, opening up that space to repair the problem will reveal the nest. Any of the homeowner purchased ant sprays will work. Besides the presence of the ant, the damaged area will also contain "sawdust" as they create their nest.