Math Formula For Roof Pitch

Rise and run formula.

Math formula for roof pitch. The calculator above can handle much of this math. Measure the rise of your roof. In the imperial unit of measurements the slope is expressed with the rise and run. Calculate the roof pitch as the proportion of rise and run.

Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. Therefore if a roof rises four inches for every 12 inches of horizontal distance it has a 4 in 12 pitch. Roof angle can be obtained by diving rise by run and take the tan inverse of the result. For example a roof with a 6 12 pitch rises 6 inches for every horizontal foot.

Let s say it is equal to 1 5 m. Includes result for hip valley factor slope factor and the roof slope in degrees. For a simple gable roof the span wall to wall will be twice the size of the run wall to ridge horizontally. 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.

Here are the equations you may use to solve for the length of the slope and the rafter. Roof pitch is expressed in ratios of 12 because it is measured by the foot. The pitch is the number of inches the roof rises compared to every 12 inches of horizontal run. The pitch value can be obtained by dividing n by 12 and divide s by the answer.

Slope factor fnd the length of the valley rafter given the following measurements. Pitch is a simple ratio of the rise to the run of the roof. Divide the slope by two to get the pitch. In civil engineering the slope is the numerical measure of the steepness of a roof.

For a roof with the ridge above one wall the span is the same as the run. 48 10 4 8. It is computed by using the simple roof slope formula. The pitch of this roof is 4 8 12.

You can also calculate roof pitch even without using a roof slope calculator. 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. Rafter rise run 1 5 6 2 25 36 38 25rafter 38 25 6 18 m. Use the following formula which also describes a right triangle.

The roof pitch formula is used to estimate the area coverage of the house. The slope is the same as the pitch. Rafter rise run this formula is from the pythagorean theorem. 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.

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. Calculate the rafter length substituting these values into the following formula. Pitch rise run 1 5 6 25.