Crawl Space Insulation Helps Keeps Floors Warm
Ever since the energy crisis of the early 1970s, many people have done a pretty good job of insulating their homes. But one area that often is neglected is the crawl space. Any crawl space that isn’t insulated is wasting energy and money. And it’s probably making the living space above it less comfortable than it could be.
So, if you have an uninsulated crawl space, don’t just sit there – do something about it-
While some itchy unpleasantness is always associated with handling fiberglass insulation, it’s really not much of a hassle to install. For the northern half of the country and beyond, you’ll need R-22 (6 1/2-inch batts).
Place the batts between the floor joists, with the reflective foil side facing up. Since you won’t have access to the stapling flanges on these batts, you’ll have to secure them by some other means. The easiest way is to use precut wire rods. These just jam in between the joists and hold themselves and the insulation in place. Space them every 16 inches.
You can also staple chicken wire to the edges of the joists, or drive nails partway into the edges of the joists, and lace wire between the nails to secure the insulation. But both of these alternatives are more work and more expensive than wire rods.
If heating ducts or plumbing supply lines run through the crawl space, you’ll want to make sure they are insulated, too.
You can cover the ducts with special 2-inch duct insulation. Water pipes are another story. Simply wrapping the pipes with insulation is not normally a good solution in a freezing climate. Insulation does not create heat, it only retains it, and it only retains it for a while.
In really cold weather, even a well-insulated pipe can freeze. The trick is to include some form of heat source. If the pipes run along the floor between joists, insulating under them will do the trick. Heat from the living space above will keep them warm. Free-standing pipes will probably need electrical heat tapes.
If your crawl space has a dirt floor, you will want to cover it with a vapor barrier. The best way to do this is to run strips of 4-mil to 6-mil polyethylene film across the floor. Overlap the strips about 6 inches at all seams and weight the overlaps with bricks or anything else that’s handy.
In addition to the vapor barrier, you should provide the crawl space with ventilation. Your total vent area should equal 1 square foot per 1,500 square feet of crawl space floor area.
If you elect to skip that vapor barrier, you’ll have to increase your vent area to 1 square foot per 150 square feet of floor area. In any case, you should install at least two vents, placed on opposite walls.
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Tags: attic insulation, crawl space, crawl space insulation, duct insulation, fiberglass insulation, house insulation, insulating crawl space, insulation