Minimum pitch of 5V metal roofing

[charliealphabravo]

Hi guys,
I have had a few files recently where I have been asked to comment on roof-over projects that were leaking or otherwise unsatisfactory. In the cases I am thinking of 5V metal roofing was used on a low-slope roof (about 1:12 or less). The specs for metal roofing that I have seen require a minimum pitch of 3:12. Does anybody know any background on this number and if there are any studies on the performance of metal roofing at lower slopes? I am thinking that there may be special lap or gasket requirements.
TIA.

 

[Pinwards]

I think it has to do with the spanning strength of the metal roofing. With a flatter roof, you have more potential for snow/ice buildup, thus need a stronger panel. 5V is relatively low profile, with large flat areas between the ribs, so is relatively weak. Other types of metal roof are suitable at flatter pitches.

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[boo1]

Typical Minimum Slope is: 3:12
Contact manufacture for actual allowable