One thing to remember is the height at the wall is the height asked for. Center height can be determined by the pitch. A standard pitch is 3/12. That means for every foot, the roof goes up 3 inches. So for a 16' wide building, you would do have the width by 3 so the center would be 3 x 8=24" or two feet taller in the center. That would be 14' on a 12' tall building. Most large RV's are no taller than 13'2" max so a 12' building is more than adequate for most RV's. One important issue in this, is anything 13' and over require a double leg. For 13'-15', we do this with a leg within a leg. 16' and above require to legs welded together to form like a ladder. 13' over 20' wide and anything 14' and above require the rental of a lift.
