Floors over unheated areas, such as crawl spaces, garages, and basements, can contribute to heat loss in an otherwise well-insulated house.

In most cases, insulating a floor is an easy job. If you are over a crawl space, though, you may have some problems with access and working space. Some careful planning should help to make things go smoothly.

To install insulation over basements or crawl space:

1. Seal all penetrations into conditioned spaces above with caulk or foam prior to insulating. Check plumbing and electrical penetrations especially those that go up through the walls.
2. Cut roll of insulation product into workable lengths or lengths separated by obstructions.
3. Place batt into framed cavity, fitting material tightly into corners.
4. Place metal insulation support rods, also known as tiger teeth, every 24' or so to support the insulation. Compress the batt no more than an inch with the curved rod.
5. Cut to fit ... do not compress the product. Stuff small areas only where necessary.

A Few Tips:

• Plan sections to begin and end at obstructions such as cross bracing.
• Cut insulation to fit between joists and make sure it is placed against the header joist.
• If you use insulation with a vapor barrier, install the vapor barrier toward the inside of the house.
• Fold up the ends of the batts so they fit snugly against the floor and header joist. This will help to prevent heat loss.
• Don't block combustion air openings for furnaces or other flame-type appliances.
• Install a vapor barrier on the earth within the crawl space.