The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
12 asphalt shingle roof slope.
High and low pitch examples two examples at each end of the spectrum.
For example a 4 12 pitch roof that is 100 square feet.
Some people recommend not installing asphalt shingles on slopes below 5 12 but a skilled roofer may well be able to make this work.
Pitched roofs begin with with slopes greater than 3 in 12.
In 12 0 25 in 12 1 19 built up roof coal tar pitch.
The 45 degree roofs seen on a frame houses are 12 in 12 but roofs can be even steeper consider the mansard roofs introduced by french second empire architects in the middle of the 1800s.
Minimum required slope x in 12 minimum required slope degrees asphalt shingles.
100 1 054 105 4ft 2.
18 43 asphalt shingles with special underlayment requirements 2 in 12.
Roofing material or system.
Additional underlayment protection with special application methods are required when asphalt shingles are installed on a low slope roof following the manufacturer s application instructions.
Roof pitch area multipliers.
Minimum required roof slope for roofing materials.
Next multiply the footprint of the roof by the multiplier below for your roof pitch to find the overall roof area.
Asphalt shingles can only be installed on roof slopes of 2 12 or greater.
Use our roof pitch calculator to find the pitch of your roof.
Asphalt shingles should never be applied to roof slopes below 2 12 2 of vertical rise for every 12 of horizontal run or 9 5.
Examples of extreme slopes range from 1 4 12 almost flat to 12 12 sloping down at a perfect 45 degree angle.
Mansard roofs with nearly vertical faces can boast a pitch of 20 in 12.
The pitch of the roof is the rise over a 12 inch run.
This number corresponds to the number of inches of rise in a 12 foot run.
Asphalt shingles continue to be the most widely installed roof covering option in north america.
Asphalt shingle options 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.
There are differing opinions as to the minimum slope for a roof but the generally accepted minimum is 3 12.
9 46 built up roof asphalt.
Asphalt shingles minimum roof slope roof pitch r905 2 2.