John writes from Colts Neck, New Jersey: "My house sits on a half basement and half crawl space, both of which are poured concrete. Even though there are two big openings between the basement and the crawl space, the floor areas over the crawl space are very cold. I want to insulate the floor over the crawlspace. The spaces between the joists are approximately 14 inches wide and about 9 inches deep. Q1: What product(s) do you recommend? Q2: Is a vapor barrier required on the product? Q3: If I go without a vapor barrier product, can I install the product with the kraft paper facing the "unheated" crawl space area (for easier installation)? Q4: Given the crawlspace is poured concrete, can I get away without also laying down a ground vapor barrier?"

Answer: For insulating the ceiling of an unheated crawlspace, we recommend Fiberglas™ insulation, specifically Kraft-faced R-30. A vapor retarder is recommended when insulating between a heated and unheated spaces. The Kraft facing on our insulation serves as your vapor retarder. We recommend that the paper be installed up toward the heated area to avoid moisture problems. It may be necessary to support the product with additional insulation supports.