Formula To Find The Slope Of A Roof

Rise run pitch where pitch is expressed in percent.

Formula to find the slope of a roof.

This is very useful information for many purposes especially for roof framing the slope sometimes called pitch is calibrated on speed squares. Conventional slope roof range between 4 in 12 and 8 in 12. Outside of the u s a degree angle is typically used. Roof slope is also called as roof pitch.

A flat roof has a slope of 2 in 12 or less. As a sanity check we confirm that the tangent of 45 degrees is 1 or that two opposed 45 degree or 12 in 12 slope roof surfaces will form a 90 degree angle where they meet at the ridge and will form 45 degree angles where they meet the wall top plate or with respect to any horizontal line in the building. For instance a 7 12 roof pitch means that the roof rises 7 inches for every 12 horizontal inches. In civil engineering the slope is the numerical measure of the steepness of a roof.

The run always remains constant at 12 inches. In the united states a run of 12 inches 1 foot is used and pitch is measured as the rise of the roof over 12 inches. There are two main categories of roofing. A low slope roof is anywhere from 2 in 12 to 4 in 12.

Image 1 12 to 12 12 roof pitch 7 12 pitch. Generally roof pitch is calculated from the same formula that describes a right triangle. How to calculate roof pitch. Here are the equations you may use to solve for the length of the slope and the rafter.

First find the slope by finding the tangent of the degrees eg. You can also calculate roof pitch even without using a roof slope calculator. The picture below shows the pitch of a 7 12 roof slope meaning that for 12 of horizontal measurement roof run the vertical measurement roof rise is 7. The slope of your roof is the ratio of vertical distance rise to horizontal distance run.

Rafter rise run this formula is from the pythagorean theorem. Roof slope style. Rafter rise run from the pythagorean theorem. Just write down the measurements you found.

In the imperial unit of measurements the slope is expressed with the rise and run. Use the following formula which also describes a right triangle. Roof pitch degree table. There s no need to simplify them.

Then multiply the slope by 12 to get the rise. By slope angle formula steepness can be obtained by dividing vertical rise by horizontal span. It is often compared to slope but is not exactly the same. That is the roof s rise.

You can use the following equations to find the length of the rafter and the slope. Tan 45o 1 00.