For roofs that will experience heavy snow or wind and will span the same distance use 2 6 rafters.
How to build a 2 12 pitch roof.
Most roof s have a pitch in the 4 12 to 9 12 range.
A low pitched roof would be 2 12 and it means that over the space of 12 inches the roof only rises two inches.
A pitch of 2 12 is the minimum pitch for shingles made of asphalt so your roof just barely makes the cut off for one of the most popular roofing material options.
The pitch of a roof is the rise the vertical angle of the roof over the run the horizontal measurement.
The pitch of the roof is a ratio.
The number of inches that the roof rises vertically for every foot of roof.
This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.
This is a way of measuring the degree of steepness of the roof.
Calculate the roof pitch.
Pitch ratios range from 2 12 to 12 12.
The table below shows common roof pitches and the equivalent grade degrees and radians for each.
You can use either 2 6 or 2 4 rafters for roofs with a 3 12 pitch or greater but it depends on the overall size of your shed.
Just enter the dimensions of the roof rise and run to get started.
For roofs that won t experience heavy snow loads a gable roof can span up to 22 with 2 4 rafters.
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.
So use a tape measure to find the height of the roof above the top wall of the building.