Do Apartments Need Title 24?

Which standards apply

Since the code was restructured, multifamily buildings have their own subchapters rather than being handled as a variant of residential. A building with three or more dwelling units is multifamily — townhouses excepted — and that is the set of requirements it is assessed against.

Within multifamily there is one further split. Low-rise multifamily means up to three habitable storeys and uses the low-rise multifamily form family. High-rise multifamily means four or more habitable storeys above grade and uses the nonresidential, hotel/motel and high-rise multifamily set instead.

What counts as a habitable storey

This is worth getting right, because it decides which form family a project is on. A habitable storey is one containing space in which people may live or work in reasonable comfort, and which has at least half of its associated volume above grade. A partly buried podium or garage level can therefore fall on either side of the definition depending on how far above grade it sits, and that single question can move a building from three storeys to four.

The discontinuity that used to exist

Until the restructuring, moving a design from three storeys to four changed the requirements sharply, because it crossed from one rule set into a quite different one. The current code deliberately aligned high-rise residential requirements with low-rise multifamily ones, so the step is far less abrupt than it was. The form family still changes at four storeys; the substance of what has to be achieved is now much closer.

Newly constructed low-rise multifamily also carries a solar photovoltaic requirement, with a short list of exceptions that have to be established for the specific building rather than assumed. Under the 2025 code, buildings of more than three habitable stories carry a PV requirement as well, unless the local utility offers no program crediting PV through virtual energy bill credits. See multifamily solar requirements.

Common Title 24 Questions

1. Does a duplex need Title 24?
2. Do triplexes and fourplexes need Title 24?
3. Which Title 24 forms does a multi-family project use?
4. What is an LMCC certificate?
5. How much does a multi-family Title 24 report cost?
6. How long does a multi-family Title 24 report take?

Explore Multi-Family

1. Apartment Unit Remodel Title 24 Requirements
2. Duplex Title 24: One Report or Two?
3. Does a Duplex Need Title 24?
4. What Is Dwelling Unit Compartmentalization?
5. Fourplex Title 24 Requirements

View all Multi-Family guides → · Permits and Compliance · Title 24 guide