Don writes from Afton, Virginia: "I am building a new home that will have a conditioned crawl space. I plan to put rigid foam insulation on the interior crawl space wall (block). Per code the rigid foam insulation must be fire rated with an R-Value of 11. Do you have a product that I can use?"

Answer: We recommend using unfaced Fiberglas insulation in the walls of a heated crawlspace. Unfaced Fiberglas insulation is non combustible and doesn't need to be covered with a thermal barrier. Owens Corning manufactures FOAMULAR® extruded polystyrene but it is not recommended for this application because it must be covered with a thermal barrier.

To install the insulation, hang it from the top of the block wall as shown in photos on the company's website. The photos show an encapsulated product being installed by the principle is the same for unfaced insulation.