Exterior, Prefab Building Type, Wood Siding Material, and Flat RoofLine When planning regulations limited what could be built in an English forest, PAD Studio devised a prefab structure that can be moved by crane. “The whole building is based around a steel frame, which provides us with the stability to be able to top-lift it easily,” explains designer Ricky Evans.  Best Photos from A Modern Mobile Home Dropped in Place by Crane