I experience in building a shed metal roofing. I decided to use sheet metal roofing for both the roof and walls for metal shed. metal roofing is a bit more expensive than using other shedding, but it is a quicker one, and I could get it in green, which blends in better with the surrounding vegetation. I put some J-trim over the ends of the strapping, for making it nice. The J-trim is actually meant for covering up the edges of the sheet metal when it's used as siding around windows, but it works pretty well for this purpose.