Smaller nail holes will be permanently fixed by this method standard roofing nails would be either 3 8 inch or 1 2 inch making a hole.
Roof repair gap in tin.
Repairing a metal roof seam with turbo poly seal is simple and it is a do it yourself p.
Typically this system is installed over a structural metal roof system where the existing roof system becomes the metal deck for the new roof system.
In this video i show you a quick way to fix a hole in a tin metal roof that might of been caused by a fallen tree limb.
How it works the metal retrofit system is installed by filling in the area of the metal panel between the metal ribs with an insulation board.
Apply uniform layer of metal roofing base coat 6 inches each way of the gap at the overlap with a paintbrush.
Both mesh and purlins reduce summertime heat penetration to the interior somewhat but i believe the significant advantage of the more effective ventilation gap provided by purlins is the reduction of the summertime temperature of the metal roofing itself.
I am not a professional roofer but.