John writes from Bettendorf, Iowa: "I am getting ready to finish off my garage. I have a couple of questions I hope you can help me with. 1. The exterior walls are 2x4's and 10' tall. Can I use material for 2x6 walls to achieve an R19 value instead of the R13 that is obtained using material for 2x4's? Or does stuffing the extra material actually lessen the value? 2. What insulation should I use to insulate above the already finished ceiling?"

Answer: Stuffing a 2x4 wall with R-19 will decrease the R-Value to R-13 so that would not be of value to you. My recommendation is to buy R-15 High Density insulation for that project. Is there an attic above the finished ceiling? If so, check the Owens Corning Web site page for Adding Insulation to an Attic.