One of the guys I work with basically did the same thing as Nate. Buy several 4x8 or 4x10 sheets of foam, cut to fit, use a foam safe adhesive to adhere the material to the door skin. If you go with a material with the radiant barrier already attached to it, you may gain slightly more R-value if you can maintain the air gap necessary to make a radiant barrier work.
I'm fortunate that the last place I bought came with a commercial insulated door. The first place I bought, I added an insulated door when I needed an impact rated (hurricane) garage door.
|