Formula To Find The Slope Of A Roof

It is often compared to slope but is not exactly the same.

Formula to find the slope of a roof. A barge rafter at the side of the gable step 2 position a level against the underside of the rafter. This means that for ever 12 inches horizontally the roof rises x number of inches. Outside of the u s a degree angle is typically used. In the imperial unit of measurements the slope is expressed with the rise and run.

Tan 45o 1 00. Measuring from the underside of the roof is usually the most accurate way to find the slope since there is no roofing material to make an uneven surface. Step 1 access a rafter. This is very useful information for many purposes especially for roof framing the slope sometimes called pitch is calibrated on speed squares.

Generally roof pitch is calculated from the same formula that describes a right triangle. Place one end of a carpenter s level against the underside of the. Roof pitch degree table. 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. Roof slope is also called as roof pitch. You can also calculate roof pitch even without using a roof slope calculator. Any of the following will give you a good measurement 1 x research source a rafter in the attic.

By slope angle formula steepness can be obtained by dividing vertical rise by horizontal span. The pitch value can be obtained by dividing n by 12 and divide s by the answer. Roof angle can be obtained by diving rise by run and take the tan inverse of the result. You can use the following equations to find the length of the rafter and the slope.

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. Rise run pitch where pitch is expressed in percent. For instance a 7 12 roof pitch means that the roof rises 7 inches for every 12 horizontal inches. Use the following formula which also describes a right triangle.

Image 1 12 to 12 12 roof pitch 7 12 pitch. Slope measures the angle of change in elevation which can be obtained by dividing rise by run and multiply the result with 100. In civil engineering the slope is the numerical measure of the steepness of a roof. Rafter rise run this formula is from the pythagorean theorem.

Rafter rise run 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. How to calculate roof pitch. 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.