Increased reliance on factory production has resulted in major changes in the efficiency of housing construction. Builders today routinely use prefabricate wall panels, pre-hung doors, windows, pre-assembled stairs, roof trusses and cabinets. Advantages of factory construction include better control of inventory and the ability to better control the quality and performance of products.

A key to understanding today's manufactured home is distinguishing it from other homes that are constructed in a factory. Most factory homes are comprised of three-dimensional modules. These modules are transported to a home site and installed on an approved foundation or support system.

Manufactured homes are constructed to comply with the national Manufactured Home Construction and Safety Standards, a uniform building standard administered and enforced by the U.S. Department of Housing and Urban Development.

Since June 1976, all manufactured homes in the United States have been built to the national Manufactured Home Construction and Safety Standards (the HUD Code.) Since adoption of the Code, which under federal law preempts all local building codes for these single-family dwellings, their quality has risen dramatically. The HUD label certifies that the home has been factory constructed, tested and inspected to comply with stringent, uniform federal standards.

The HUD Code, administered by the Department of Housing and Urban Development, is the counterpart to national model codes for site-built housing. These model codes include the Uniform Building Code of the International Conference of Building Officials, upon which Oklahoma local governments base their building codes.