0 pitch 1 00x the roof area.
1 to 4 ratio roof slope.
Roof pitch is often expressed as a ratio between rise and run in the form of x 12.
This is read as a one in twelve slope.
18 4o inches per foot.
Generally such roofs have a pitch ranging from 1 2 12 to 2 12.
Flat roofs are not perfectly flat in reality they need a small slope for water runoff.
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.
The pitch of a roof is its vertical rise over its horizontal span.
The table below shows common roof pitches and the equivalent grade degrees and radians for each.
Often you express roof pitch as the ratio between the rise and the run in the form of x 12.
Flat roofs which aren t perfectly flat require a small slope to allow for water runoff.
Most roof s have a pitch in the 4 12 to 9 12 range.
However most often a ratio of pitch also fraction is slang used for the more useful slope of rise over run of just one side half the span of a dual pitched 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.
For example a pitch 1 12 means that per every twelve yards of building length the rise will be equal to one yard.
1 pitch 1 01 2 pitch 1 02 3 pitch 1 03 4 pitch 1 05 5 pitch 1 085 6 pitch 1 12 7 pitch 1 16 8 pitch 1 21 9 pitch 1 25 10 pitch 1 31 11 pitch 1 36 12 pitch 1 42.
This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.
For instance if you travel 3 inches vertically and 3 feet 36 inches horizontally the slope would be 3 36 or 1 12.
Calculating a slope gradient.
We can divide roofs into the following categories.
4 3 1 slope.
You can divide roofs into these categories.
3 1 or 3 to 1 percent slope.
Since this is a flat roof or nearly flat roof.
Horizontal to vertical slope ratio to 1 percent slope degrees slope slope ratio.
Slope gradients are written as y x where y is a single unit in rise and x is the run.
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.
The slope ratio represents a certain amount of vertical rise for every 12 inches of horizontal run.
If the rise is 6 inches for every 12 inches of run then the roof slope is 6 in 12 the slope can be expressed numerically as a ratio.
Both numbers must use the same units.
