Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run.
Roof pitch tables metric.
Use the following formula which also describes a right triangle.
For roof slopes expressed as x in 12 rise in run the roof pitch multiplier is determined by finding the square root of rise run 1.
Enter run the flat level length then click pitch angle or rise to select then enter other known dimension angle or pitch.
Image 1 12 to 12 12 roof pitch 7 12 pitch.
A roof pitch multiplier also called a roof pitch factor is a number that is multiplied by the area covered by a sloped roof to produce the area of the actual surface of the roof.
If there is an overhang the rafter overhang is measured in millimetres from outside wall to inside fascia board level across.
You can also calculate roof pitch even without using a roof slope calculator.
Visit this page using a phone or tablet to directly measure pitch and angles.
In essence a roof pitch chart is provided as a rough guide usually by a roofing company to help you see what the average roof pitches tend to be.
Let s say it is equal to 1 5 m.
Roof pitch and corresponding angles.
They have a pitch ranging from 4 12 to 9 12.
Calculate the roof pitch as the proportion of rise and run.
We included a roof pitch chart below the 7 12 example image and the calculator below that.
Calculate the length of a rafter in metres using the roof slope measured in degrees and the gable wall width in metres.
Usually they come in the form of a roof pitch diagram chart but other times it will be presented to you in a conversion format.
Rafter length from roof slope in degrees using metric measurement.
If this isn t practical then perform the same measurement on the underside of the roof.
Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch.
Pitch rise run 1 5 6 25.
Drag sliders to animate the results and diagram.
The triangle diagram will be re drawn to scale with all dimensions marked.
High pitched roofs often need extra fasteners and their pitch can be as high as 21 12.
This is very useful information for many purposes especially for roof framing the slope sometimes called pitch is calibrated on speed squares.
Roof pitch calculator results explained 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.
Calculate the rafter length substituting these values into the following formula.
Measure the rise of your roof.
Roof pitch degree table.
