Six inches of attic insulation used to be enough, but in most parts of the country today 12 inches is considered the minimum. The time and money you invest in this project will be paid back in lower energy bills for years for come. If you use the new poly-wrapped fiberglass insulation you won't have to deal with skin irritation or the nuisance of itching. Since it's more compact than traditional paper-backed insulation, it's less bulky to transport, too. An insulation contractor will charge $845 to install 40 rolls of R-25 insulation in a 1200-square-foot attic. You can cut and lay the wrapped insulation over the existing insulation for $500, saving over 40 percent of what the contractor charges.
You need the following: scissors, utility knife, measuring tape, straight edge and scrap of plywood to put underneath the roll so you don't damage the floor or dull your knife when cutting.
Protect yourself from the dust by wearing a long-sleeved shirt and pants, and wear knee pads, a dust mask and safety goggles. This is a very physical job involving a lot of crawling and stooping in confined areas of the attic. It'll take the better part of the day, especially if you have to cut and fit the insulation around framing and heating ducts.