Roof Slope Ratio Calculator

1 as a ratio of the rise to the run for example 1 in 20 2 as an angle almost always in degrees 3 as a percentage called the grade which is the rise run 100.

Roof slope ratio calculator.

Slope tilt or inclination can be expressed in three ways. A 4 12 is a roof slope that rises by 4 inches for every 12 inches across. Roof pitch refers to the measurement of the slope of a roof and you express this as a ratio. Roof pitch is the measurement of a roof s vertical rise divided by its horizontal run.

This is very useful information for many purposes especially for roof framing the slope sometimes called pitch is calibrated on speed squares. This forms an angle of 18 5 between the horizontal section and the roof and creates a gentle incline that is seen as a midpoint between a low pitch and medium pitch roof. With a 12 in 12 slope the wall or roof rises 12 inches in a 12 inch run a 12 in 12 slope 45 one could be inclined to assume that a 6 in 12 slope would equal half of that 22 5. The rise is the height of the roof and the run is the horizontal span as pictured above.

First convert the pitch to a slope. For example if you measure 4 inches the pitch of your roof is 4 12. A ratio of 1 1 62 is known as the golden ratio and therefore the vast majority of roof pitch in degrees charts you see will be working to this ratio at the very least. 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.

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. A 6 rise in a 12 inch 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. To find the angle of a roof in degrees convert the pitch to a slope then convert to degrees by finding the arc tangent of the slope.

To do this simply convert the rise and run as a fraction to a decimal form eg. This will give you the rise over run or pitch. Rise run rise run slope. For example if a roof has a pitch of 4 12 then for every 12 inches the building extends horizontally it rises 4 inches.

The roof pitch is the slope of the rafter.