Prefabricated building or volumetric modular construction refers to a method of building a structure off-site, rather than a description of the finished product. Prefab buildings are typically built 60 to 90 percent off-site in a three-dimensional form, designed to be constructed at one location, and then used by occupants at another.
Prefabricated buildings, or prefab buildings, are similar to traditional buildings with the exception that most of the construction of the building parts is done inside a factory, according to specific designs. After the design and production of the building parts, they are taken to a building site where the building is completed.
The Four Stages of Prefab Building：
Design approval by the end user and any regulating authorities
Assembly of module components in a controlled environment
Transportation of modules to a final destination
Erection of modules to form a finished building
Concurrent activities compress overall project schedule
Because prefabricated buildings are mostly completed inside a factory, under assembly-line conditions, the production can be controlled, unlike conventional buildings where things such as bad weather, regular inspections and delay in shipment of materials needed for construction can lead to costly delays. Prefabricated homes also allow the owner to subsidize the cost of the house through the provision of labor by hiring a contractor and some friends to chip in, so as to bring the price of the whole package down.