There are some opinions that standing seam metal roof minimum slope is 12 but it increases the possibility of leaking on the few first days of snow arrival.
Minimum slope for metal roof with snow.
To get the minimum pitch for a metal roof the vertical rise per foot is divided by the horizontal slope.
The minimum slope for lapped non soldered seam metal roofs with applied lap sealant shall be one half unit vertical in 12 units horizontal 4 percent slope.
The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.
Standing seam manufactures allow applications of metal coverings on slopes of 12 or even more.
You can often see such examples of use over metal decks.
The minimum slope for lapped non soldered seam metal roofs without applied lap sealant shall be three units vertical in 12 units horizontal 25 percent slope.
Most metal roofs will have minimum pitches of three in twelve but this might sometimes go down depending on whether there are special installation procedures issued by the manufacturer regarding that particular roofing material.
A minimum slope of 1 inch per foot is recommended in snow country.
Metal roofing systems have a good track record of performance in harsh winter environments as long as they are properly designed.
The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.
In country with heavy snow and tough winter days the metal roof minimum slope is recommended to be 1 12.
The minimum pitch for metal roof shingles and lapped non soldered panels is 3 12.