4 3 1 slope.
1 to 4 ratio roof slope.
For example a pitch 1 12 means that per every twelve yards of building length the rise will be equal to one yard.
The pitch of a roof is its vertical rise over its horizontal span.
We can divide roofs into the following categories.
This is read as a one in twelve slope.
3 1 or 3 to 1 percent slope.
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.
A roof that rises 4 inches for every 1 foot or 12 inches of run is said to have a 4 in 12 slope.
Most roof s have a pitch in the 4 12 to 9 12 range.
Flat roofs are not perfectly flat in reality they need a small slope for water runoff.
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.
Slope gradients are written as y x where y is a single unit in rise and x is the run.
Horizontal to vertical slope ratio to 1 percent slope degrees slope slope ratio.
Often you express roof pitch as the ratio between the rise and the run in the form of x 12.
Generally such roofs have a pitch ranging from 1 2 12 to 2 12.
For instance if you travel 3 inches vertically and 3 feet 36 inches horizontally the slope would be 3 36 or 1 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.
Calculating a slope gradient.
The table below shows common roof pitches and the equivalent grade degrees and radians for each.
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.
Flat roofs which aren t perfectly flat require a small slope to allow for water runoff.
18 4o inches per foot.
You can divide roofs into these categories.
Since this is a flat roof or nearly flat roof.
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.
Roof pitch is often expressed as a ratio between rise and run in the form of x 12.
You can go by the measurements taken by walking the roof.
0 pitch 1 00x the roof area.
