In termite-prone areas, rigid foam insulation should not be used on the exterior of foundations below grade. To discourage termites and allow for inspection, some codes require that rigid foam insulation on the exterior of the foundation be held at least six inches above the ground. Wood siding should be at least 8 inches above the ground to avoid soil contact. On interior walls, a four-inch pest control inspection area or gap is often required just below the sill plate to allow for termite inspections. This strip of bare wall can be painted white to make inspections easier. Non wood-based building materials or treated wood should be considered for areas with a high probability of termites. Install metal flashing at the base of the wall to block termites and keep plants at least 18 inches from siding.