Kevin writes from Troy, Michigan: "I have a detached garage I would like to insulate. I would like to start with the ceiling. I am thinking of using the Kraft R-13 between the 16" centers. If I staple them and they are on the ceiling why do I have to cover the insulation with drywall or plywood?"

Answer: You need to cover the insulation because the paper facing is combustible and cannot be left exposed. It is a code violation to leave the Kraft paper vapor retarder exposed.