Formula To Find Slope Of Roof

Roof pitch degree table.

Formula to find slope of roof.

Rafter rise run this formula is from the pythagorean theorem. 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. Slope measures the angle of change in elevation and it can be found by dividing the rise by run. First find the slope by finding the tangent of the degrees eg.

Slope tan degrees. It is often compared to slope but is not exactly the same. Any of the following will give you a good measurement 1 x research source a rafter in the attic. Tan 45o 1 00.

Then multiply the slope by 12 to get the rise. Place one end of a carpenter s level against the underside of the. Rafter rise run from the pythagorean theorem. Rise run pitch where pitch is expressed in percent.

Use the following formula which also describes a right triangle. The page provides you the slope pitch of roof formula to find the slope roof pitch and run. Run refers to the change in the horizontal movement. Outside of the u s a degree angle is typically used.

The overhang of a rafter at the end of the roof. 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. In civil engineering the slope is the numerical measure of the steepness of a roof. You can use the following equations to find the length of the rafter and the slope.

If you know the angle of the roof in degrees you can find the roof pitch by converting the angle in degrees to a slope then finding the rise by multiplying the slope by 12. For instance a 7 12 roof pitch means that the roof rises 7 inches for every 12 horizontal inches. Image 1 12 to 12 12 roof pitch 7 12 pitch. The slope of the roof is determined by the vertical rise in inches for every horizontal 12 inch length or run a common formula is.

Here are the equations you may use to solve for the length of the slope and the rafter. Roof slope is also called as roof pitch. X rise 12 run this means that for ever 12 inches horizontally the roof rises x number of inches. In the imperial unit of measurements the slope is expressed with the rise and run.

Rise points the vertical height per unit of horizontal movement or run. 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. By slope angle formula steepness can be obtained by dividing vertical rise by horizontal span. Step 1 access a rafter.

You can also calculate roof pitch even without using a roof slope calculator. How to calculate roof pitch.