Mike writes from Los Angeles, California: "I have a 2x4 wall that I need to insulate to r-19. There are exposed posts and beams that show on both sides of the wall, which do not allow an overlay of rigid insulation, or furring the studs. The wall is only 18ft x 9ft, so cost is not really an issue. Is there a product or combination of products that will fit INSIDE the 2x4 wall that will give me an r-19 value?"

Answer: The maximum R-value of Owens Corning FIBERGLAS® Insulation for a 2 x 4 wall is R-15.