Roof pitch is a measurement of a roof s slope expressed as a ratio.
Roof slope degree.
A pitch over 9 12 is considered a steep slope roof between 2 12 and 4 12 is considered a low slope roof and less than 2 12 is considered a flat roof.
Most roof s have a pitch in the 4 12 to 9 12 range.
It s just a little math.
To see what the degree equivalents are for standard rise in run roof pitches see our page quick reference.
Some of the most common roof pitch types are conventional slope type roofs designed with pitch ranging from 4 12 to 9 12.
This means that the rise of the slope goes up or down 8 inches for every 12 inches.
The following table shows how the same common roof slopes can be expressed using rise in run ratios degrees and percentages.
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.
This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.
Sangle tan 1 1 m 2 m 26 6.
The most precise way to find the roof s slope is by measuring it from the underside.
Roof slope expressed as rise.
To put it in perspective the angle of this slope would be around 30 degrees.
Roof pitches exceeding the level of 9 12 or approximately 37 degrees are termed steep slope roofs.
Slope as angle for an elevation of 1 m over a distance of 2 m can be calculated as.
The 45 degree roofs seen on a frame houses are 12 in 12 but roofs can be even steeper consider the mansard roofs introduced by french second empire architects in the middle of the 1800s.
Although there is no single standard roof pitch used on all sloped roofs factors such as roofing materials and local climate help to determine the appropriate range of pitches for a given building.
Pitched roofs begin with with slopes greater than 3 in 12.
Also see our page quick reference.
The slope of a roof or pitch is determined by how many inches the roof rises over 1 foot or 12 inches.
Measuring the slope from the rafters.
Example slope as angle.
Either way let s see how you can calculate the slope of a roof without using a roof slope calculator.
These are utilized in residential applications.
The table below shows common roof pitches and the equivalent grade degrees and radians for each.
An example for a steep sloped roof is 8 12.
See below after the table for directions on how to convert any roof slope from one form to another even roof slopes not shown in the table.
Access one of the rafters then take the measurement this way.
Last updated july 10 2020.
Mansard roofs with nearly vertical faces can boast a pitch of 20 in 12.
