Tom writes from Media, Pennsylvania: "My attic is unfinished and has blown in insulation that comes right to the top of the 2"x8" floor. I laid flooring on top of the studs. Now according to your calculator I do not have enough insulation up there and I can't lay any more on the floor. The space is 1100sq feet and unheated. Should I go ahead and insulate the ceiling (A shaped roof line) of the space to make up the difference? And the 2 end walls?"

Answer: Actually, if there are no gaps between the flooring and the blown-in insulation it is OK to place unfaced insulation on top of the flooring. Adding insulation to the rafters of an unconditioned attic will not help add R-value and is not recommended.