Modular construction refers to a method of building a structure, rather than a description of the finished product. Modular buildings are typically built 60 to 90 percent "off-site" in a three-dimensional form, designed to be constructed at one location, and then erected on site.
While modules are being constructed in a factory, site work is occurring at the same time, therefore reducing labor, financing and supervision costs.
Unique to prefab construction is the ability to simultaneously construct a building's floors, walls, ceilings, rafters and roofs. During site-built construction, walls cannot be set until floors are in position, and ceilings and rafters cannot be added until walls are erected. On the other hand, with modern modular methods of construction, walls, floors, ceilings and rafters are all built at the same time, and then brought together in the same factory to form a building. This process often allows modular construction times half of that of conventional, stick-built construction.
Traditional building techniques, quality manufacturing and third-party administered random inspections, are combined with testing and certification services for quality control and assure that temporary modular buildings are built in strict accordance with appropriate local, state, and national regulations and codes. We would argue that due to the extra durability needed for travel, factory-built buildings are built better than conventional structures.