Figure 3-14. Vented Crawl Space with Concrete Walls and Insulated Ceiling
Figure 3-14 illustrates a vented crawl space with a concrete foundation wall. The insulation consists of foil-faced polyisocyanurate attached to the bottom of the floor joists, with all joints sealed and taped to act as an air barrier, and to prevent moisture accumulation in the wood structure. Batt insulation is placed between the floor joists over the rigid foam.