Rise Over Run Formula For Roofs

The following table shows the roof pitch rise in run equivalents for all roof slopes in degrees from 1 to 72.

Rise over run formula for roofs. Typically in construction we express roof slopes as units of rise per single unit of run such as 3 inches of rise per 12 inches of run or 3 per ft. This page offers you the rise and run formula to find the pitch slope angle of the roof of a building. Rise run pitch use this when you express the pitch in percent pitch tan angle use this when you express the angle of the roof pitch in degrees what is the standard pitch of a roof. Simply locate a roof rafter board place the end of the level against the bottom edge and measure from the 12 inch mark vertically to the bottom edge of the rafter.

3 in 12 or 3 12 slope as an angle. Let s say it is equal to 1 5 m. 3 if we know the grade of a road for example 3 then angle a arctangent rise run which equals arctangent 03 1 7184 degrees and the ratio 1 in 1 tan a which equals 1 in 1 tan 1 7184 1 in 1 03 1 in 33 333. For example if you measure 4 inches the pitch of your roof is 4 12.

Slope the slope of a roof is represented as x 12 where x is the number of inches in rise for every 12 inches of run. The pitch value can be obtained by dividing n by 12 and divide s by the answer. Rafter rise run 1 5 6 2 25 36 38 25 rafter 38 25 6 18 m. Slope measures the angle of change in elevation which can be obtained by dividing rise by run and multiply the result with 100.

This will give you the rise over run or pitch. Calculate the rafter length substituting these values into the following formula. Calculate the roof pitch as the proportion of rise and run. Here is an online rise and run calculator which helps to calculate pitch slope and angle with the help of rise and run values.

Pitch rise run 1 5 6 25. Other than the 45 roof slope which is 12 in 12 none of the standard roof pitches 5 in 12 6 in 12 etc are equal to a whole degree. Slope as rise run e g. This is very useful information for many purposes especially for roof framing the slope sometimes called pitch is calibrated on speed squares.

In roof pitch calculator pitch value can be obtained by dividing n by 12 and divide s by the answer. Grade rise run 100 which equals 1 19 081 100 5 2408.