Asphalt shingles offer a good-better-best range for building owners to choose from, and of all prevalent roofing materials, they are easiest to install.
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Calculating Roof Area
Gable Roof Area
To find the length of a rake on a gable roof, multiply its horizontal distance (the roof’s run) by the slope conversion factor in Slope, Hip/Valley Conversion, below, then multiply by the length of the ridge to find the area.
Rake Length = Run x Slope Factor
Gable Roof Area = Rake Length x Ridge Length
To find the length of a hip or a valley, multiply its horizontal distance (run) by the hip/valley factor in Slope, Hip/Valley Conversion, below.
Hip or Valley Length = Run x Hip/Valley Factor
Figure: Slope, Hip/Valley Conversion
Slope (in. per ft.)
Multiply a roof’s run by the correct factor to get the length of its rake. To find the length of hips and valleys, multiply the correct factor by the horizontal distance of a hip or valley.