After putting out wasp traps, or spraying their nests to remove the wasps that inhabit it, you must then remove the nest itself. Wasps may continue to come back to the area, or surrounding areas to build new nests. They do not give up easily. The only way to keep them from coming back is to make the area inhabitable to them, which depending on how your home is built, may not possible. You may have to call an exterminator.