The termite company sprayed the home, but each time the termites return. They have damaged the floors and are even eating the paper off the wallboard. Years ago, exterminators used chlordane to kill termites by contact. Chlordane production was banned in the late 1970s as a suspected contaminant that threatened water systems and wells. Since the ban, the chemicals used to treat for termite infestation have been repellents.
Repellents work as long as the home being treated is surrounded by the chemical barrier.
Any minute gap in the treatment and the termite will get through. No treatment company can guarantee that the ground around the home is so saturated that there are no gaps. Then there is the baiting system. With baiting, plastic cylinders are buried at strategic locations around the building, and a bait is placed inside the station to attract termites. Once the termite is discovered, a poison bait is placed in the container and the termite transfers the poison to the whole colony, killing the colony.