Roofing Costs
Figuring the cost of roofing is not an easy task, unless you know where to begin. There are many different types of roofing materials and different aspects of the roofing process itself. Because roofing costs can be combined into materials and labor, or materials only, there are separate steps to help you decide. Also, roofing materials come as asphalt shingles or metal sheets; therefore, there are two distinct steps to calculating both. Figuring roofing costs is not difficult once you get the hang of it, and, with a little practice, you will be calculating at ease. Does this Spark an idea?
Instructions
1. Measure the length and width of the roof. Have a helper hold one end of the tape measure while you pull the other end. You can usually measure the entire length (C) of the roof in one pull. Measure the width of one side of the roof (A or B) and multiply that by 2. See the drawing for reference.
2. Determine the square footage of the roof. Multiply the length by the width. For example, a roof that is 20 feet long and 20 feet wide would be 400 square feet (length times width equals square footage).
3. Calculate the square footage for putting on shingles. Shingles come in bundles of about 25 shingles. Three bundles equal 100 square feet. So divide, for example, the 400 square feet of roof surface above by 100 (three bundles) shingles. Therefore, it would take four squares of shingles to do a 20-foot-by-20-foot roof. If you want to know the number of bundles, just multiply the amount of squares (four) by three (number of bundles in a square). You would need 12 bundles of shingles for this job.
4. Calculate the number of sheets of metal needed for a 20-by-20 foot roof. Because a typical sheet of roofing metal is 42 inches wide and you are working with 10-foot pieces, you will need to convert everything into inches. Take your 10-foot length and multiply by 12 (inches). The sheet of metal is 120 inches long and 42 inches wide. Multiply the length by the width to get square inches. One sheet of metal is equal to 5,040 square inches. Now, convert the roof into square inches (20 feet long by 20 feet wide converts to 240 inches long by 240 inches wide). To get the square inches of the roof, multiply 240 by 240 and you get 57,600 square feet. Now, divide 57,600 (area of roof in square inches) by 5,040 (area of one sheet of metal) and you get 11.4285 pieces of 10-foot metal that is 42 inches wide. Round that number to 12 pieces---because you can't buy half a sheet of metal.
5. Calculate the materials and labor cost of the roofing job. Because a new roof in 2009 will cost you between $50 and $65 per 100 square feet, materials and labor, take the total number of square feet of the roof and divide that by 100. Now, multiply that number by, say, $65. So, if your roof is 400 square feet, you would divide that by 100 and you would get 4. Four times $65 equals $260 to do a 400 square-foot roof, including material.
6. Calculate the cost of just the materials. You may decide to do the roofing job yourself. If this is the case, then just take the 400 square foot roof from above and divide that number by 100, and that number comes to 4. Because the cost of materials in 2009 only is $25 to $30 per square, and you have 4 squares to be roofed, then you will multiply 4 by $30. The cost of materials only for this example would be $120.
Tags: square feet, square inches, inches wide, sheet metal, that number, divide that, length width
