Please note: For your convenience, this calculation has been rounded up slightly.
Important reminder: Every effort has been made to ensure the accuracy of this calculation. But before purchasing materials for any project, please check amounts with your suppliers or contractors.
Roofing a house is usually a job best left to professionals. Pros often are accustomed to working on sloping high surfaces, can purchase materials cheaply, and have specialized tools to make the job go faster. When dealing with a roofer, it is good to know how much area needs to be covered, and this calculator will enable you to do that.
A few tips: To figure the size of your roof, see our square footage calculator. In roofing terminology, a "square" is 100 square feet. Composition shingles (asphalt or fiberglass) come in bundles that cover 1/3 square. Roofing comes in rolls 3 feet wide and 36 feet long, for a coverage of about 1 square.
When installing roofing over bare wood, roofing felt -- often called tar paper -- is laid down first. A roll of 15-pound felt covers about 4 squares; a roll of thicker 30-pound felt covers 2 squares. When ordering any of these materials, add 15 percent for waste.