Understanding Factory-Built Homes
Factory-built homes can be confusing for home buyers. Although modular and manufactured homes are both built in factories, they follow entirely different standards and codes. While inspecting these homes is similar to a conventional home inspection in most respects, the foundation is a critical difference — and your inspector should know how to identify anchoring methods and construction types.
Note: Foundation certifications and code compliance inspections are not included in a standard home inspection. However, if your lender requires a foundation certification, we can help — see our Foundation Certification page for more details.
Manufactured / Mobile Homes
Manufactured (mobile) homes are built on a permanent steel chassis and transported to their installation site. The chassis becomes a permanent structural component — removing it would compromise the home’s integrity. These homes are built to the federal HUD Code (24 CFR 3280) and are typically exempt from state and local building codes, except for foundation installation rules. Common characteristics include:
- Transportable in one or more sections
- Width of 11'4" to 16'0" in transport mode
- Minimum 400 sq. ft. for a single-section unit
- Exterior wall height typically 7'6" or 8'0"
- Built on a permanent steel chassis
- Chassis beams: 10” for 12–14 ft widths, 12” for 16 ft widths
- Roof slopes range from 0.5:12 to 4.4:12 (max 20°)
- Can be placed on piers, slabs, or full basements
- Double-wide units joined to function as one home
- HUD label permanently attached to each transportable section
All manufactured homes must be anchored to the ground using approved methods. For FHA and VA loans, an engineering certification is often required to verify the foundation is permanent. In Wisconsin, manufactured homes installed on or after April 1, 2007 must comply with the Wisconsin Manufactured Home Installation Manual (2009 Revision) .
Modular Homes
Modular homes are also built in factories, but they follow the same state and local building codes as site-built homes. They offer more flexibility in layout and design — including two-story models and complex floor plans — and may be indistinguishable from a conventional home once finished.
Due to the controlled factory environment, modular construction often results in higher precision than site-built construction. The building process may involve fully constructed modules, partial sections, or individual wall panels. Modular homes are typically identified by a data plate found under the kitchen sink, inside a bedroom closet, or near the electrical panel.
Buying a Modular Home? A standard home inspection is usually appropriate. If you're unsure, feel free to contact us — we're happy to help clarify which inspection fits your needs.