Abstract: Prefabricated foldable building units are described that have one or more of the following advantages. They are more easily prefabricated, more easily transported to building sites without requiring special permits, unloadable and unfoldable at the building sites without using cranes (they can be unloaded using ground-level lifting rigs and unfolded using, for example, a cable mechanism), allow precise and fast completion at the building site, and allow significant reduction in the scope of work to be completed on-site, where costs and scheduling are far less manageable. Further, methods for unloading and unfolding foldable building units are described that obviate the need for one or more cranes that can be expensive and project-complicating, thereby opening up a significant percentage of building sites for placement of prefabricated foldable building units.