Assembly of standardized building components at a location other than the building site.
Units may include doors, stairs, window walls, wall panels, floor panels, roof trusses, room-sized components, and even entire buildings. Prefabrication requires the cooperation of architects, suppliers, and builders regarding the size of basic modular units. In the U.S. building industry, the 4-by-8-ft (1.2-by-2.4-m) panel is a standard unit; the architect's drafted building plans and the supplier's prefabricated wall units are based on multiples of that module . Advantages of prefabrication include the cost savings of mass production, the opportunity to use specialized equipment to produce components, and standardization of parts for quick assembly and erection. The major drawback is in assigning responsibility for quality control. See also precast concrete .