Prefabrication Prefabrication is the practice of assembling components of a structure in a factory or another manufacturing site and transporting complete assemblies or sub-assemblies to the construction site where the structure is to be located. The term is used to distinguish this process from the more conventional construction practice of transporting the basic materials to the construction site where all assembly is carried out. The term prefabrication also applies to the manufacturing of things other than structures at a fixed site. It is frequently used when the fabrication of a section of a machine or any movable structure is shifted from the main manufacturing site to another location, and the section is supplied assembled and ready to fit. It is not generally used to refer to electrical or electronic components of a machine, or mechanical parts such as pumps, gearboxes, and compressors which are usually supplied as separate items, but to sections of the body of the machine t