1 To 4 Ratio Roof Slope

Slope gradients are written as y x where y is a single unit in rise and x is the run.

1 to 4 ratio roof slope.

Flat roofs which aren t perfectly flat require a small slope to allow for water runoff. You can go by the measurements taken by walking the roof. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. 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.

A roof that rises 4 inches for every 1 foot or 12 inches of run is said to have a 4 in 12 slope. The table below shows common roof pitches and the equivalent grade degrees and radians for each. 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. Flat roofs are not perfectly flat in reality they need a small slope for water runoff.

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. We can divide roofs into the following categories. Horizontal to vertical slope ratio to 1 percent slope degrees slope slope ratio.

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. Generally such roofs have a pitch ranging from 1 2 12 to 2 12. This is read as a one in twelve slope.

4 3 1 slope. 3 1 or 3 to 1 percent slope. This is the slope of geometry stairways and other construction disciplines or the trigonometric arctangent function of its decimal. 0 pitch 1 00x the roof area.

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. 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. Most roof s have a pitch in the 4 12 to 9 12 range.

18 4o inches per foot. Both numbers must use the same units. Often you express roof pitch as the ratio between the rise and the run in the form of x 12. The pitch of a roof is its vertical rise over its horizontal span.

Roof pitch is often expressed as a ratio between rise and run in the form of x 12.