Melissa writes from Claysville, Pennsylvania: "We have a new house and are using our large attic for storage. Should we insulate the attic ceiling (the roof of the house) or not? I have been told that you don't insulate this area because the house needs to "breath." Is it standard to insulate interior walls?"

Answer: Yes, you can insulate the attic ceiling. The Owens Corning website has information about this application.

Interior walls are usually insulated for acoustic purposes to reduce sound transmission from one room to the next.