Termites move from soil to structure
Subterranean termite colonies usually start below ground on wood debris left behind during construction. Termites then extend the colony by "shelter tubes" built over, or inside, material that spans between the soil and building (see drawing below). In short -- anything that links the soil to the building can serve for termite access.
Termites enter houses through a number of "weak, or entry, points" (right) such as foundation walls and posts. These areas should be regularly inspected for termite activity.
