Where and how should perimeter slab insulation be applied?
The insulation can be applied outside (Figure 2) or inside (Figure 3) the foundation wall. Exterior applications require a metal flashing or durable finish for protection. The insulation can also be placed vertically along the foundation wall (Figure 3) or horizontally under the slab (Figure 4). Perimeter slab insulation can give termites access, so be sure to provide a termite shield (Figure 8). Some jurisdictions do not allow external insulation because the foundation must be visible for termite inspection.
