The problem is your shed. Move it to a dry location not shaded by trees. Enclose it fully. Insulate 4 walls and roof. Put in an insulated concrete floor with vapour barrier. Keep the interior heated to above the condensation point.I have a covered RV shed with both ends open to drive through. The floor is limestone road base. Can this be a cause of rust and corrosion? All the framing is rusted and everything parked in there develops rust in places. Anyone else have this problem? I cant find any good info on it and want to know before I get it all out of there. Shed is about 5 years old.