Roof Pitch Multiplier Table

A roof pitch multiplier also known as a roof pitch factor is a number that when multiplied by the area covered by a sloped roof gives the actual area of the roof.

Roof pitch multiplier table.

Some sources consider low slope to include 3 12 pitch roofs. The first thing that you need to understand before picking any selections from a roof pitch multiplier chart is to ensure that it s affordable. Low slope roofs are from 0 to 3 12 in pitch. The maths behind this number is that it is the square root of rise run 2 1.

Determine how many square feet of roof area a building has by measuring from the ground. For roof slopes expressed as x in 12 rise in run the roof pitch multiplier is determined by finding the square root of rise run 1. Since pitch is the rise over a 12 inch run divide the run by 12 to get the multiplier in this case 120 12 10. This roof pitch table displays a multiplier for adding for different roof pitches.

If you know the pitch of a roof you can use the numbers in the following pitch table to do the following. This table provides the hip and valley factor for common roof pitches as well as the underlying equation for the factor. We excluded roof multipliers for pitch below 3 and above 12 for the following reasons. The roof pitch multiplier table is very helpful in giving correct and reliable roof measurements and uses pythagorean theory.

The hip and valley factor is a number that is multiplied by the actual run horizontal distance of a common rafter to determine the length of a hip or valley rafter. The total run is the distance from the peak to the edge of the roof which in this case is the total width divided in half which is equal to 10 feet or 120 inches. A roof pitch multiplier also called a roof pitch factor is a number that is multiplied by the area covered by a sloped roof to produce the area of the actual surface of the roof. Now solving for c in the equation above gives.

The formula for the roof pitch multiplier comes from the famous pythagorean theorem. How to find your what roof pitch category. If asphalt shingles are to be installed on a low slope roof special steps are required to avoid short roof life and roof leaks. Notes to the table above.

Roof pitch multiplier table. Typically the steeper the roof is the higher the price will be. Where a is the rise of the roof b is the run of the roof and c is the rafter hypotenuse of the triangle with side lengths a and b. Accurate roof calculations are achieved using this table and all you need to do is measure the roof width and length and then you are ready to do a roof pitch measurement.