Jim writes from West Bend, Wisconsin: "I have a walk up attic. I want to put in a bedroom that is 12x16 with a 9 foot ceiling and will have hydronic baseboard heat. The room will sit against one exterior wall that faces north. The remainder of the attic will be unfinished, unheated and used for storage. As this home used to be a barn, it has a mansard style roof with no roof vents or soffit vents. I know I will need to insulate the wall that is the exterior wall of the home and apply a plastic vapor barrier on it, but what about the rest of the walls of the bedroom, the ceiling and the rafters in the bedroom? Since the bedroom sits on the outside wall, part of the wall/ceiling is sloped due to the existing house rafters. Do I need to insulate these, and use a vapor barrier on them? Should I use the foil/bubble insulation to staple up instead? The original rafters are 24" on center, while all the rest of the framing for the new construction is 16" o.c."

Answer: Since you are creating a heated living space inside your attic, (and the rest of the space will be unheated) we recommend all of the areas around the living space be insulated. In other words, treat all walls of the bedroom as exterior walls. We recommend Kraft-faced insulation be installed with paper toward the warm-in-winter side. The ceiling or rafters of the heated living space should be insulated in this fashion as well. Finally, make sure there is ventilation between the insulation and roof deck at the slopes.