Brian writes from Lafayette Hill, Pennsylvania: "I am insulating the floor above an unheated crawl space with a concrete floor, so I do not have any ground moisture. I bought R-25 fiberglass roll insulation. Do I need to put a vapor barrier between the unfaced insulation and subfloor? If so, what is the best way? 6 ml plastic stapled to the joists?"

Answer: Click here to see information on the Owens Corning Web site about insulating crawl spaces under floors.