James writes from Atlanta, Georgia: "I'm confused. Your response to Bill (Oct 30, 9:11am) suggested using insulation without a vapor retarder between the joists in a crawlspace. The Owens Corning info sheet that I picked up at Home Depot today says "Always install insulation with vapor retarder toward the warm in winter side of the house." This is the section under "Floors" and discusses crawlspace. We already have plastic sheets covering the ground. Which do I use, with or without vapor retarder? If I use insulation with vapor retarder, does the retarder go on the ground side or the floor side? Do I use precut wire to hold up the insulation or staple the folded strip of paper to the joist if you recommend a vapor retarder? A seemingly knowledgeable Home Depot employ said to use insulation with the vapor retarder toward the ground side and staple the strip of folded paper on the edge of the bat to the joists and not use the precut wire for support. I really need these questions cleared up so that I don't get mold, mildew, etc."

Answer: Always install the insulation with the vapor retarder toward the warm side of the structure in heating climates. In a vented crawlspace, the warm side is usually up, closest to the floor above the crawlspace.

The Kraft paper should be touching the subfloor. The thickness of insulation you select will determine how close the insulation comes to the bottom of the joist.

The insulation should be installed all the way back at the end of each joist run so that it touches the band joist. You want complete coverage under the house. There will usually be a narrow joist space along the walls that runs parallel to the joists. Insulation should be cut to fit this space.

There are often both pipes and wires in crawlspace floors and occasionally a junction box. Water pipes should be insulated and you will need to insulate carefully around electrical wiring and boxes.

Insulation should be placed around cross braces by cutting it and pushing it between the braces.

Once the insulation is in place between the floor joists, insulation hangers or nylon straps can be used to hold the product in place.