Are your heating and cooling costs are going through the roof? You might be right! An attic with poor insulation can cost you big bucks. The Department of Energy estimates attic insulation can substantially decrease the money you devote each month to keeping a comfortable temperature. Anywhere from 10 to 15 percent. Whether you do the job yourself or a hire a contractor, you’ll experience an immediate and long-term benefit. As you plan to insulate the attic, consider the following factors.
Types of Insulation.
There are many different types of insulation, all of which are readily available at your local home center. For the tightest nooks and crannies of the attic, choose loose-fill insulation. Most common, though, is blanket-style insulation, made of either fiberglass or rock wool. The material comes in rolls or square batts. For contractors and do-it-yourselfers, it’s presized to fit between most studs, rafters, and joists. To seal up air leaks around chimneys, plumbing stacks, or similar components that penetrate the building envelope, hire a pro. They will apply closed or open cell spray foam insulation.
So, You Want to… Insulate the Attic: R-Values.
How much is enough insulation? In part, that depends on what type of insulation you’ve chosen to install. Each type rates differently on the R-value scale. R-value is a measure of how well a product blocks the passage of heat and cold. Most current building codes call for R-50 insulation in the attics of new homes. R-38 is for insulation retrofit into existing dwellings. But the age of the home isn’t the only variable. One must consider its geographical location. Energy Star provides an easy-to-read chart that specifies the recommended R-values for different parts of the country.
But while attic insulation is critical, ventilation of the attic is equally important. Without ventilation, moisture can accumulate and condense. It will eventually rot the insulation and compromise structural integrity. Ventilation goes a long way toward neutralizing the seasonal threat posed by ice dams. Ice dams are capable of causing extensive, expensive damage.
Some experts discount the value of attic vents, particularly in warmer climates. Most, however, agree that vents in the attic not only keep the house more comfortable, but also prevent potential problems. The typical attic includes ventilation: on gable ends, along the roof ridge, and in soffits. If you’re planning to install attic insulation, it makes sense to think about
So, You Want to… Insulate the Attic: Before You Start.
Before you begin the installation process, no matter what type of insulation you’ve chosen, do some prep work. In attics without lighting, plug in a temporary clip-on work lamp. A flashlight won’t cut it here. Look around for discoloration or any other evidence of a roof leak. Make all necessary repairs before continuing. Where there’s no flooring, lay down 3/4-inch plywood panels, so you have a safe platform. Remember that most insulation products release hazardous particles. If you choose to insulate the attic yourself, wear full protective gear and a dust respirator.
Notes on Installation.
Insulation expands once unpackaged. Leave it wrapped until you are ready to use it. Bear in mind that if you compress insulation in order to make it fit, the product loses much of its R-value. A better strategy is to measure the span into which you’re placing the insulation, before cutting the product to size. To cut blanket-style insulation, place the product over a piece of plywood, with its paper (or foil) side down. Lay a two-by-four on top, temporarily compressing the insulation to a manageable thickness. Finally, run a standard utility knife along the edge of the lumber, through the insulation, and down to the plywood.