A question from Tony: "I live in Chicago and want insulate the basement walls and then apply drywall. What is the best method to do this? Do I need a plastic vapor barrier?"

Either Kraft faced or un-faced exterior wall insulation can be used to insulate basement walls, with R-values ranging from 11 to 21. Faced insulation should be placed between the studs with the vapor retarder facing the interior of the room in heating climates. The flange on the facing can be stapled to the inside or face of the stud.

For the band joist, use un-faced, cut-to-fit pieces of insulation and place them snugly into the space.

Where local codes require a vapor retarder, we recommend a material of not less than 1 perm. We do not recommend the use of polyethylene on any below-grade walls. Vapor retarder primers are an option on drywall when using faced insulation.