Gauge of galvanized roofing?

PPBART

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?

OldNBroken

Anything less than 24ga is basically residential quality. I rarely recommend anything less. 29ga is bottom of the barrel and not recommended for much of anything. You are correct, it is flimsy and you can actually tear it with your bare hands. Even if you are trying to be cheap 26ga should be bare minimum you consider.

Unfinished metals I always recommend minimum 22 ga as thinner gages will corrode and rust out very quickly. Some materials we use are intended to rust such as cor-ten but that is why they are 20 or 22ga usually.