What is a manufactured home and how does it differ from a modular home?

A manufactured home (also known as a mobile home) is a single or multi-sectional home built on a permanent frame, like a steel undercarriage/chassis, with a removable transportation system (hitch and wheels). The unit is permanently attached to a site-built foundation and is subject to the 1976 federal standards established by the Department of Housing and Urban Development (HUD).

A modular home is constructed in a factory using conventional home floor joists and delivered to a site on a trailer or flat bed truck. The delivered home may be in the form of panels that are assembled at the site, may be pre-cut and assembled on site, or may be pre-built and delivered in one piece. The home, panels or pre-cut panels are lifted from the trailer and attached to a foundation. A modular home may be single or multi-storied. Modular homes are not subject to HUD standards, but must be built to state and local Uniform Building Codes.

What if my modular has a permanent chasis?

Current Fannie Mae Guidelines state:

"XI, 304.01: Manufactured Homes (06/15/07)

Any dwelling unit built on a permanent chassis and attached to a permanent foundation system is a manufactured home for purposes of Fannie Mae’s guidelines. Other factory-built housing (not built on a permanent chassis), such as modular, prefabricated, panelized, or sectional housing, is not considered manufactured housing and continues to be eligible under the guidelines stated in this Guide."


"XI, 304.02: Other Factory-Built Housing (08/24/03)

A. Modular home. It must be built under the Uniform Building Code that is administered by the state agency that is responsible for adopting and administering building code requirements for the state in which the modular home is installed.

B. Factory-built home that is any other type of prefabricated, panelized, or sectional housing. It does not have to satisfy either HUDs Federal Manufactured Home Construction and Safety the home is installed. The home must conform to local building codes in the area in which it will be permanently located.

We do not have minimum Standards or the Uniform Building Codes that are adopted and administered by the state in which requirements for width, size, roof pitch, or any other specific construction detail for modular homes, or any other types of factory-built homes. Rather, each home must have sufficient square footage and room dimensions to be acceptable to typical purchasers in the subject market area. Since quality can account for large differences in the values of factory-built homes, it is important for the appraiser to become familiar with the features that affect the quality of a factory-built home so that the information can be included in the appraisal report (if needed) to support his or her opinion of value."


It appears Fannie Mae Guidelines differ from North Carolina regulations. North Carolina has what is commonly referred to as "on-frame" modulars. This type housing is built on a permanent metal chasis, but often bears a resemblance to a manufactured home. However, "on-frame" modulars are built in accordance with the North Carolina Site Built Housing Code and have a "modular" seal affixed to the interior,  generally near the circuit box. In most states, this type dwelling is treated similar to manufactured housing. However, in North Carolina due to the seal that is affixed stating it is a modular home, this type dwelling is generally treated as a modular home. (Modular homes in North Carolina that are built without permanent chasis are not issued a seal.) 

In summary, factory built modular homes, either with or without steel floor framing system, must meet the requirement of North Carolina Residential Code edition in force at the time the home is manufactured. However these facts are of minimal consequence in regard to the financing of modular home construction. It is recommended that you discuss your options with your lender, as lending programs vary greatly for "on frame" and "off frame" modular's.  It also must be noted that in today's ever-changing financial environment, mortgage programs are dynamic. For this reason it is recommended that you keep in close contact with your lender to stay updated on these changes. It is also noted that the "on-frame" modular loans can sometimes be more problematic in nature due to the ever-changing lending programs associated with this type of construction.

Additional modular home with steel frames information:

It is acceptable under North Carolina State Building Code and therefore acceptable to the Department of Insurance for a modular home to be constructed with a steel and wood floor framing system similar to and in many cases identical to a HUD approved manufactured home (chassis). A modular home with this type of steel and wood floor framing system is commonly called an "on-frame" modular. Modular homes which have a floor system framed entirely of wood, as in a conventional site-built home, are commonly called “off-frame” modular’s. In the approval process, both the “off-frame” and “on-frame” modular’s are considered to be simply two different methods of framing a floor system. Both systems must be designed to meet the loading requirements of the North Caroling State Building Code. The “on-frame” method of constructing a floor system utilizes structural steel girders as support for the floor joists, while the conventional “off-frame” method typically has the joists supported by built-up wood girders and the exterior foundation walls. The Building Code does not prohibit structural steel members from being used when constructing either a site-built home or an “on-frame” modular home. The fact that the structural steel framing system in an “on-frame” modular is also used as the transportation system to move the home from factory to job site is an indication of the strength of the floor framing system. In other words, in addition to supporting the floor, the steel framework must be capable of withstanding transportation loads caused by Travel over the highway. The North Carolina State Building Code does not prohibit use of the steel floor framing system to transport the home so long as the system is not structurally damaged during transit. When installed on site, all modular homes are required to be placed on a Code complying foundation system.