The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
Normal roof pitch michigan.
With regards to the pitch the building standard code bs 5534 recommends a minimum pitch of 200 for slate roofs.
The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run.
Any pitch higher than 9 12 is considered a steep pitch.
They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.
Roof pitches exceeding the level of 9 12 or approximately 37 degrees are termed steep slope roofs.
Pitches of less than 2 12 are considered flat roofs even though they may be very slightly angled.
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.
This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.
Minimum roof pitch for shingles.
A flat roof would have a 2 12 pitch while the average roof pitch would be between 4 12 and 9 12.
The pitch of the roof is determined by the vertical rise in inches for every horizontal twelve inch length.
What is the minimum slope for an asphalt shingle roof.
But since there is still a wide variety of slate roofing systems there are occasions when the minimum pitch can go down to as low as 15 0 depending on the uniqueness of the 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.
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.
Pitches above 9 12 are very highly angled and are designated steep slope roofs.
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.
However you can only use this pitch with built up roofing or specialized synthetic roofing.
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 these multipliers may also be used to convert the horizontal pro jected area to the actual roof area for sloping roofs.
These are utilized in residential applications.
The most commonly used roof pitches fall in a range between 4 12 and 9 12.
Pitches lower than 4 12 have a slight angle and they are defined as low slope roofs.