James writes from Arlington, Virginia: "I recently purchased a 1941 brick colonial. It has an unfinished attic with plank flooring covering the middle 60 percent or so (to allow it to be used for storage). The exposed portion reveals only about 4"-5" of old white insulation (unfaced) between the joists.

I'd like to do something in the short-term to improve the insulation. Is it a problem to install insulation (between the joists as high as possible, and then additional insulation perpendicular to the joists) only on the unfloored portion? This will mean the middle section of the attic has only the original insulation level, while the edges have a much higher R-value."

Answer: Your plan will be better than doing nothing but by your own estimate, you will not be increasing the insulation R-value in 60 percent of the attic. Most of a home's heat loss goes out through the attic so it is important to have that part of the home well insulated. There is more information about insulating an attic on the Owens Corning Web site at Adding Insulation to an Attic and Frequently Asked Questions.