Math Formula For Roof Pitch

Therefore if a roof rises four inches for every 12 inches of horizontal distance it has a 4 in 12 pitch.

Math formula for roof pitch.

Pitch rise run 1 5 6 25. L 1 8 feet l 2 10 feet pitch 1 1 pitch 2 0 8 length of valley rafter a geometry sketchpad showing intersecting roofs with different pitches is attached. Calculate the rafter length substituting these values into the following formula. 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.

The pitch value can be obtained by dividing n by 12 and divide s by the answer. Use the following formula which also describes a right triangle. By slope angle formula steepness can be obtained by dividing vertical rise by horizontal span. 48 10 4 8.

For example a roof with a 6 12 pitch rises 6 inches for every horizontal foot. Now divide the rise by the multiplier to get the pitch eg. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. Roof pitch is expressed in ratios of 12 because it is measured by the foot.

Rise and run formula. Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. You can also calculate roof pitch even without using a roof slope calculator. For a simple gable roof the span wall to wall will be twice the size of the run wall to ridge horizontally.

Let s say it is equal to 1 5 m. Measure the rise of your roof. Here are the equations you may use to solve for the length of the slope and the rafter. Calculate the roof pitch as the proportion of rise and run.

Includes result for hip valley factor slope factor and the roof slope in degrees. In civil engineering the slope is the numerical measure of the steepness of a roof. The roof pitch formula is used to estimate the area coverage of the house. Roof slope is also called as roof pitch.

In the imperial unit of measurements the slope is expressed with the rise and run. Divide the slope by two to get the pitch. The pitch of this roof is 4 8 12. Slope factor fnd the length of the valley rafter given the following measurements.

Rafter rise run this formula is from the pythagorean theorem. It is computed by using the simple roof slope formula. The slope is the same as the pitch. Obtain the pitch or slope angle of a roof by calculating the ratio of the change in the roof s height to the corresponding horizontal distance.

The calculator above can handle much of this math. For a roof with the ridge above one wall the span is the same as the run. Other formulas needed to work with roofs are as follows. The pitch is the number of inches the roof rises compared to every 12 inches of horizontal run.