Tim,
My house is 60 feet long by 40 feet deep and has a hip roof. Is there a simple way to figure the roof square footage so that I can figure how many shingles I will need to reroof?
Jay Roach
Charles Town, West Virginia
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Jay,
I would need a little more data to get an accurate estimate of material. You failed to give me the distance from the gutter up to the peak of the roof. This measuring line needs to be at a right angle to the roof ridge and the gutter. Getting this dimension gives us the overhang and the pitch at the same time. But I can still get you fairly close without that measurement.
Having framed countless hip roofs the old-fashioned way with a framing square, I can tell you that the linear ridge at the top of the roof is 20 feet long. You calculate the length of a hip ridge by simply subtracting the short leg of the roof from the long leg. 60 - 40 = 20. If you take out a piece of paper and draw your roof, you will quickly see you can divide the roof into 8 right triangles and two rectangles.
For sake of discussion I am going to assume the measurement from the gutter to the peak is 27 feet. The short leg of the two rectangles is 20 feet so you would multiply 27 x 20 x 2 = 1,080.
The area of one right triangle would be approximately 20 x 27 divided by 2 = 270. I say approximately becasue I don't know your roof overhang. The base of the triangles will probably be a little more than 20 feet. Since you have 8 of these, you multiply 270 x 8 = 2,160. So a very rough guesstimate is 3,240 square feet plus 10 percent for waste at the hips, starter shingles and all the caps you need. I'll bet you will need approximately 36 squares of roofing.
Tim Carter
www.askthebuilder.com
W3ATB