Dan writes from Philadelphia, Pennsylvania: "I am renovating an old warehouse in Philadelphia, and covering the brick walls with framing and drywall so that I can insulate them. The framing is 2x6's, so I can get R-19 fiberglass insulation between the studs, and as suggested by an architect, I'm leaving 2" for rigid insulation. Seeing how much rigid insulation costs, and noting that I am covering about 3,000 square feet of wall area, I am moved to seek out an alternate to the rigid insulation to fill this space. I think compressing 3 1/2" fiberglass insulation into the space won't help, but is there a good solution with fiberglass? For instance, if there is a 2" fiberglass batt, what would the r-value be?"

Answer: Owens Corning insulation products are either fiberglass or extruded foam. I don't know of a suitable alternative. Two inches of Fiberglas™ insulation is approximately R-8.