Many types of structures are built in a factory and designed for long-term residential use. In the case of modular homes, units are built in a factory almost to completion, transported to the site location and installed. Any remaining construction is done on-site.

Modular homes fall under the auspice of the model building code enforced in the jurisdiction where the home is to be located. These can be the BOCA National Building Code, the ICBO Uniform Building Code, The Southern Standard Building Code or the IRC One- and Two-Family Dwelling Code.

In panelized and pre-cut homes, essentially flat units (factory-built panels or factory-cut building materials) are transported to the site location and assembled.