Do I need a Title 24 report to place a manufactured home on my lot?

Not for the home itself, which is built to federal standards and governed by Title 25. Ask HCD or the local building department which installation permits apply.

Is the federal "Title 24" for manufactured homes the same as California's?

No. The HUD construction standards are in Title 24 of the Code of Federal Regulations, Part 3280. California's Title 24, which contains the Energy Code, is part of the California Code of Regulations.

Can a factory-built home go in a mobilehome park?

According to HCD's handbook, yes: on a foundation, in a park built after 1 January 1982, where a zoning designation or conditional use permit allows it. It is still built to the California code, Energy Code included.

Does Title 24 Apply to Manufactured Homes?

Q: Does an addition to a mobile home need Title 24?

The CEC says no: Title 25, not Title 24, governs manufactured homes, including additions to the unit.

Not to a HUD-code manufactured home: the CEC's single-family compliance manual says Title 25, not Title 24, governs manufactured homes, additions to the unit included. Factory-built housing is different, because it is designed to the California Building Standards Code, the Energy Code included.

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Two homes from a factory, two rulebooks

A manufactured home, in the Health and Safety Code definition HCD quotes (Section 18007), is a home built since 15 June 1976 on a permanent chassis, transportable in one or more sections and designed as a single-family dwelling with or without a foundation. Factory-built housing is a home or a major part of one made off site, in modules or closed panels, and assembled on site; HCD's bulletin on the 2025 code notes that it does not include a manufactured home or mobilehome. Both come out of a factory; only the second is built to California's Title 24.

HUD-code homes: federal construction, state oversight

HCD points to federal law for homes built on or after 15 June 1976: Title 42 of the U.S. Code from Section 5401, with construction standards in Part 3280 of Title 24 of the Code of Federal Regulations. That federal "Title 24" is a different book from California's Title 24, which belongs to the California Code of Regulations. State law is the Manufactured Housing Act of 1980, with regulations in Title 25.

The CEC's 2025 single-family manual settles the energy question. Asked whether the Energy Code applies to an addition to a manufactured home, it answers: "Title 25, not Title 24, governs manufactured homes, including additions to the unit." In a mobilehome park, jurisdiction sits with HCD; for a home on private property it may sit with the local building department. HCD's own page adds that alterations to an existing manufactured home that bears, or must bear, a HUD label are subject exclusively to HCD regulation, plan review and inspection, wherever the home stands. There is no CF1R for the home itself.

Factory-built homes: California code, built indoors

HCD's factory-built housing handbook says these homes are designed and built to the current California Building Standards Code, the same as site-built homes (Title 25, Section 3070), and its code matrix includes Part 6, the Energy Code. Energy compliance is part of the approved design, and the local building department then permits and inspects the foundation, site work and installation. Once assembled, a factory-built home is treated as site-built for the life of the structure, so later alterations go through the local department like any other house.

The handbook treats it like a house in planning terms too. It may be installed wherever similar dwellings are zoned, local requirements may not differ substantially from those for other homes of the same size, and the Attorney General has ruled that local governments may not require use permits for it in residential areas. It may also go on a foundation in a mobilehome park built after 1 January 1982, where zoning or a conditional use permit allows. HCD does not register or title it as chattel.

HCD's 2025 code bulletin says new factory-built housing plans submitted on or after 1 January 2026 follow the 2025 code, and an approved plan stays valid for 36 months from approval. The Energy Code sets its requirements by climate zone, so ask the manufacturer which zones its approved energy documentation covers. Factory-built ADUs have their own page: prefab ADUs and Title 24.

What does need a Title 24 report

Site-built work is ordinary construction under the Energy Code: a site-built house or ADU on the same lot as a manufactured home, or an addition to a factory-built home after it has been installed. So are panelized kits whose framing stays open for inspection: the handbook says open-framed prefabricated construction is not factory-built housing, because the local department can inspect it on site. Not sure which kind of home you have? Look for a HUD label on a manufactured home, or HCD's factory-built housing insignia. For a specific project, start with do I need a Title 24 report.