Shopping for roofing
Roofing materials are sold by the "square," a measurement equal to 100 square feet. An average two-story, 2,500-square-foot house with a 4-in-12 pitch roof requires about 1,500 square feet of roofing, or about 15 squares. When estimating, add 10% to 15% for waste.

Note that certain types of asphalt shingles with cooling granules and metal roofing with appropriate pigmented coatings help reduce energy costs and may qualify for a federal energy efficiency tax credit of up to $1,500. Check with your distributor to see if the roofing you choose meets Energy Star requirements and if the manufacturer offers a certification statement that you can use to obtain the credit. Currently, the credit is applied toward roofing materials installed by the end of 2010.

Asphalt shingles also called composition roofing, are by far the most popular type of roofing material. They are readily available, durable, relatively inexpensive and can be installed by an experienced do-it-yourselfer if the roof is not too steep. The individual shingles feature slits that divide the shingle into three pieces or tabs that give the finished roof a textured appearance. For this reason they are sometimes called "3-tab shingles."

Asphalt shingles feature a fiberglass or cellulose core sandwiched between layers of asphalt. A top coating of mineral helps protect the shingles from damage by the elements. Some varieties include zinc- or copper-coated ceramic granules that help prevent the growth of algae and moss, a problem often found in the warm, humid climates of the Southeast. Some types have especially high wind ratings that are especially suited for coastal regions.