Modular homes are built in a factory as three-dimensional modules that may be combined on-site to make one-, two- or three-storey homes. Typically, a bungalow will consist of one or two modules, while a two-storey home will use four or five, or more modules.
The homes are typically set on full-perimeter foundations—a crawl space or full basement—but may also be placed on surface-mount foundations.
Insulation, air/vapour barrier, plumbing, wiring, exterior siding and other construction details are largely completed in the factory. Interior work is usually well advanced, including drywall, trim, flooring, cabinets and bathroom fixtures.
Finishing the home on-site generally takes a couple of weeks, sometimes more, depending on the size, style and features of the home. Some features are best done on-site, such as brick siding and some types of flooring.