Attic Insulation: Old Homes May Be a Little Thin on Top
Hot air rises. If you have insufficient attic insulation, it just keeps rising, right out of your house. Or in a hot climate, it allows the burning sun to make an oven of your abode.
The older your house, the more likely you are to need a booster shot. If insulation does not cover your attic floor joists, you definitely need more, but even if the joists are covered, you may be under-covered. To get an estimate of your current R-value, measure the thickness of the insulation, note the type, and do a simple Internet search.
Attic Insulation: Know Your Area's R-Value
You can learn the recommended R-value for your area (between R-30 and R-49 in the United States) with a quick call to the county planner (after waiting on "hold" for 30 minutes), or perhaps to a friendly insulation contractor.
While you are in the attic, it's wise to look around for problems, particularly mice, rats,0 and bats. You need to plug up any holes allowing access from outside. This also is the time to look for any dirty areas around openings to the ceiling, such as bathroom exhaust fans, which would indicate unsealed openings that are allowing air to pass from the room to the attic.
Attic Insulation: Protect Soffit Vents
Also while in the attic, make sure you have rafter, or soffit vents. If you don't, you need to install them before adding insulation. Never cover vents with insulation. If your house was built before 1950, you may have vermiculite insulation. Vermiculite, small pellets, has been known to contain trace amounts of the carcinogen asbestos--anyone working in the attic should have asbestos training.
You can use either batts (blankets) or blown-in, loose material when adding insulation--it typically doesn't matter what you have now. If using batts, lay them perpendicular to the joists, over the existing insulation. Batts easily can be installed by the DIYer, and some home-improvement stores rent blowers for loose insulation.
Attic Insulation: Wear Protection
The job is not pleasant. Anytime you handle insulation, you should be protected with long sleeves, gloves, dust mask, goggles, and even a cap. If you've been in the attic on a hot summer day, you probably have an idea about which time of year you do not want to do this project.
Do not use faced batts, with paper or foil on one side, as this can trap moisture in the insulation. If you have lighting cans, shield them, unless you know they are rated for contact with insulation. Also, you may have to raise any electrical junction boxes, which by code must remain visible.
By taking the time to replace your insulation, you can keep the house warmer as well as keep some cash in your pocketbooks as you keep your energy costs down.