How to Calculate Shingles Needed

Video Transcript

"Hi, I'm Tim Gipson. I'm going to talk to you about how to calculate shingles for a roof. Now, the most accurate way to calculate shingles for the roof is to look at the planes of your roof. So if you look at this one behind me, it's actually a roof that it's pitched down on four sides of the house. So each side creates a triangle. And we'd want to find the area of that triangle. And there are calculation methods to do that that's takes a little bit of geometry to understand, but if you can make some measurements and do some calculations, you can do that. Now, for a lot of homes, they just have a double pitch roof. So again, if you can measure the length and then the width of each side of the roof, you can calculate that total area. Now, if you're not able to get up there and measure, then we can do some estimating. You can...if you know the length and the width of your house, you would take the width and you would divide that by two, and that would give you half or the half of the roof plane. Now, to calculate actually how long that roof is, you want to add about 20 percent of the feet. So in other words, if your house is 10 feet wide, then you would estimate that the roof is actually 12 feet wide, and then you would calculate that by the length. So you'd take 12, if your house is 40 feet long, that would be 480 square feet. Multiply it by two for both sides, and you'd have 960 square feet. Now, regardless of what method you use, the actual measurements or estimating, once you get your total square footage, you're going to divide that by 100, and that'll tell you how many square of shingles that you need. And what the square means is 100 square feet. And then you just need to find out what your type of shingle comes in. Typically, shingles are sowed...sold three bundles to a square, or each bundle of shingles would cover about 33 and a third square feet. So you would, again, calculate your square, the squares required, multiply that by three. So if you had 400 square of roofing that was required...or excuse me, four square, which would be 400 square feet, then you would divide that by 100, and you'd get...you need four square. So with the four square, divide that by...or multiply that by three, and you need 12 bundles of shingles to do that area. So again, you find out your square footage, divide that by 100 to find out how many squares, and then multiply by three if your bundles come in three bundles per square or whatever...or divide by whatever fraction they are. I'm Tim Gipson, and that's how to calculate shingles for your roof."