I looked into those metal buildings. I was thinking about replacing the 40YO barn and rebuilding my hay storage barn. I thought maybe I could get a deal on the two. After getting quotes (very high even if you do it yourself) I decided the barn would have to wait and I tore down the old hay barn and built a pole barn with tin roof. It is not really great but the roof don't leak. I just put in a main beam and then ran 16 foot 2x4's off to each side. I used the old tin on two side to keep rain out or most of it. I wish I had ordered the heavier metal roofing but just used the local home owner suppliers for tin. I did screw the tin down rather than nail. 32x~80.