The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
Minimum roof pitch in michigan.
The minimum requirement is 2 12.
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.
The 2 12 number is rise over run or two units of vertical for every 12 units horizontal.
The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run.
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 roof pitch is also subject to the standards set forth by the various building codes used in the respective regions.
Where the roof sheathing is less than 3 4 inch 19 1 mm thick the nails.
However you can only use this pitch with built up roofing or specialized synthetic roofing.
Fasteners for asphalt shingles shall be galvanized steel stainless steel aluminum or copper roofing nails minimum 12 gage 0 105 inch 3 mm shank with a minimum 3 8 inch diameter 9 5 mm head complying with astm f1667 of a length to penetrate through the roofing materials and not less than 3 4 inch 19 1 mm into the roof sheathing.
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.
Shingles of all types need to have a slope to function properly.
This can be accomplished by measuring the number of inches the roof rises vertically for every 12 inches it extends horizontally.
They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.
For example a roof with a 6 inch 12 pitch is one where it rises 6 inches vertically for every 12 inches of the horizontal run.
That works out to about nine degrees if that works better for you.
This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.
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.
You could also opt for a pvc flat roofing membrane.
Asphalt shingles continue to be the most widely installed roof covering option in north america.
Importance of a roof pitch.
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.
