Figure 2.7 — This graph illustrates a building’s reduction in heat loss when it is insulated with various thicknesses of spray-in-place urethane foam. Note: above 3 inches, the insulation benefit tops off quickly. The graph is not exact, but it shows, in general, what happens as additional insulation is added to the surface temperature. In other words, by super-insulating, the surface temperature of the inside of the exterior walls comes very close to the room temperature. This prevents condensation, that, in turn, prevents mold growth.