Gauge of galvanized roofing?
I've got a storage shed in the backyard that was built in 1985, corrugated metal roof looks good as new, absolutely no rust in sight. Across the yard is a workshop built in (I think) 1987-88, with a corrugated roof that is almost totally covered with rust. I'm considering replacing the metal on the shop and would like some info on gauge(s) of corrugated metal roofing available today.
Looking at Lowes and Home Depot, I can only find "grade 80 full hard 29 gauge steel" -- looks and feels pretty flimsy. What grade/gauge should I be looking for?