The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
Minimum roof pitch michigan.
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.
The minimum requirement is 2 12.
Rise multiplier rise multiplier 1 to 12 1 01 6 to 12 1 12 2 to 12 1 01 8 to 12 1 20 3 to 12 1 03 12 to 12 1 42 4 to 12 1 06 15 to 12 1 60 5 to 12 1 08 18 to 12 1 80.
Roof slope multipliers for roof components of sloping roofs multiply by the figures given below to obtain the cost per square foot of horizontal projection.
For roof slopes from two units vertical in 12 units horizontal 17 percent slope and up to four units vertical in 12 units horizontal 33 percent slope underlayment shall be two layers applied in the following manner.
The minimum slope for lapped nonsoldered seam metal roofs with applied lap sealant shall be one half unit vertical in 12 units horizontal 4 percent slope.
The minimum roof pitch is also subject to the standards set forth by the various building codes used in the respective regions.
Lap sealants shall be applied in accordance with the approved manufacturer s installation instructions.
Asphalt shingles continue to be the most widely installed roof covering option in north america.
They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.
The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run.
Shingles of all types need to have a slope to function properly.
What is the minimum pitch slope of an asphalt shingle roof.
There are some standing seam metal roofing options available from atas and other manufacturers that can be installed on a roof with pitch of 1 12.
So you would need to pick the right option as most regular standing seam metal roofs will require a roof pitch of 2 12 or even 3 12 at a minimum.
That works out to about nine degrees if that works better for you.
The minimum slope for standing seam roof systems shall be one quarter unit vertical.
The chief reason for having a roof pitch is to redirect water and snow away from the roof and avoid any percolation that might result from stagnation of water on the roof.
However you can only use this pitch with built up roofing or specialized synthetic roofing.
The 2 12 number is rise over run or two units of vertical for every 12 units horizontal.
