8′ x 12′ Salt Box Shed (SB-4) By Mary Steele on August 1, 2013 in Portable Building Styles, Salt Box Sheds This 8′ x 12′ salt box style shed was constructed with vinyl siding and a green steel roof for added durability as it sits on the banks of the Chesapeake Bay. Model SB-4. Construction Features Customization Options Rent to Own