My new shop's roof overhang was too short to install conventional rain gutters of any type that I could find, so I chose to try 3 inch OD Sch. 20 Drain/Waste PVC, as a possible alternative, to fit over the edge of the corrugated tin roof, allowing enough clearance for the door to open (out) and close. It's not the best or easiest install, but it works for me, for now. Other ideas are welcomed in the comments section.