The most common rafter spacing is 24 inches and 5 8 inch plywood is recommended for that.
1 2 inch slope roof.
Roof slopes are most commonly defined by the rise over run ratio.
We can divide roofs into the following categories.
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.
A 2 12 roof slope means your roof has 2 inches of vertical drop for every 12 inches of horizontal distance.
Low pitched roofs are generally difficult to maintain and you need special materials to prevent leaks.
For example a pitch 1 12 means that per every twelve yards of building length the rise will be equal to one yard.
The slope ratio represents a certain amount of vertical rise for every 12 inches of horizontal 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.
Roof slopes slope rise run in inches conventional slope 4 in 12 and up.
Low slope 2 in 12 to 4 in 12.
Simply put it s a shallow roof.
The table below shows common roof pitches and the equivalent grade degrees and radians for each.
For rafters spaced 20 or more inches apart 1 2 or 5 8 inch plywood is recommended.
Enter run the flat level length then click pitch angle or rise to select then enter other known dimension angle or pitch.
This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.
Flat 0 in 12 to 2 in 12.
If a roof slope rises say 4 inches when measured 12 inches along the bottom of a horizontal roof truss.
Generally such roofs have a pitch ranging from 1 2 12 to 2 12.
Flat roofs which aren t perfectly flat require a small slope to allow for water runoff.
Generally these roofs have a pitch from 1 2 12 to 2 12 from 4 2 to 16 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.
Drag sliders to animate the results and diagram.
That means the roof doesn t shed water as easily as steeper roofs which is why choosing the right type of roofing material is so important.
Most roof s have a pitch in the 4 12 to 9 12 range.
These roofs have a pitch less than 4 12.
The triangle diagram will be re drawn to scale with all dimensions marked.
Flat roofs are not perfectly flat in reality they need a small slope for water runoff.
