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If I had a 50×50 building with a 10/12 gabled roof from one side to another, how do I figure up the amout of square footage (or squares) above the 9ft. wall height?
Inside the “triangle” part of the wall in other words. I know that 1/2 the base times the height is the area of the triangle, but how do I figure out the height from only the base and the pitch?
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/ <—– this area
/
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| | <—- 9ft wall
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50ft.wide
Thanks.
Replies
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Sketch your gable end on a piece of paper. If I understand your question, it will be a triangle with the base equal to the width of the end of the building and a peak in the middle. Draw a vertical line from the peak to the base. The line will be perpendicular to the base. You now have two triangles. If the roof is the same pitch on both sides, the triangles will be mirror images of each other. The base of each will be half the width of the building.
A pitch of 10/12 means the roof rises 10 feet for each 12 feet of horizontal run. So, your height is ten-twelfths of the base of one of the "half" triangles.
Using your numbers, the width of the building is 50 feet. So, each of the two triangles will have a base of 25 feet. The height of the triangle is 10/12 x 25 = 20.833 feet, or 20 feet 10 inches. The area is 1/2 base times height. For the entire gable the base is 50 feet and the height is 20.833 feet, so the area is 1/2 x 50 x 20.833 = 521 square feet. This is the same thing as saying each "half" triangle has a base of 25 feet and a height of 20.833 feet, so its area is 1/2 x 25 x 20.833 = 260 square feet, but there are two of them, so 260 + 260 = 521 (rounded off).
Sorry it took me so long to say for a simple answer: the pitch is the rise divided by the run.
*So, then I would multiple 521*2 gables and get 1042 sqft. which is 10.42 square? A square is 100 sqft., right?Trying to figure how much siding it will take and how much it will cost (materials and labor) to install it.
*Don't forget a waste factor, and if you are only siding the gables you might want to beef up the labor rates.
*Daniel, to answer your question, how do you figure the height of a gable with only the span and the pitch, take 1/2 the pitch times the span, then divide by 12 to get the height in feet. EX: 50 foot span and 10/12 pitch, 25 X 10 = 250. 250/12=20.8 feet. Simple, simple. And easy to remember. Good luck. -Rich
*I've got the feeling that we're mixing "pitch" and "slope ratio". A 10/12 pitch is hell of a slope, with a rise almost as big as the whole width of the house! You're talking a 20" rise per foot! Ok, so you mean the rise is 10" over a 12" run, right?fv
*To answer your 05:54 pm Sept. 20 question, yes, you are correct, that is the exact area. Tommy is right, too, you have to order extra for waste. There's more waste on a gable than a rectangular space because of the angled cuts. I don't have enough experience to say how much overage you should order.
*Not sure if you're asking me or not. You should know better if you are since I didn't even know how to figure the square footage (-:When a roof pitch is given, does it usually mean feet or inches?
*Usually it's based on inches, but it can be anything as long as the units are the same - inches to inches, feet to feet, miles to miles. If you have a 10/12 rise and run, it just means for every 12 units you go horizontally, you will go up 10 units.
*No I wasn't asking. I really don't know how much extra to order. I'm not a builder, so I would have to defer to the experts on how much extra to order. I'm just an engineer, so I'm good with the math!
*i would love that building for my mistakes... i mean my tools and scaffolding
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If I had a 50x50 building with a 10/12 gabled roof from one side to another, how do I figure up the amout of square footage (or squares) above the 9ft. wall height?
Inside the "triangle" part of the wall in other words. I know that 1/2 the base times the height is the area of the triangle, but how do I figure out the height from only the base and the pitch?
/
/ <----- this area
/
------
| |
| | <---- 9ft wall
------
50ft.wide
Thanks.