California Building Code (CBC)

The California Building Code (CBC) is Part 2 of the California Building Standards Code (Title 24, California Code of Regulations). It is the primary code governing the design and construction of most commercial, institutional, mixed-use and multifamily residential buildings in California. The CBC is based on the International Building Code (IBC) with California-specific amendments adopted by state agencies.

The 2025 California Building Code is the current edition, effective January 1, 2026, replacing the 2022 CBC. It is built on the 2024 IBC. Because the code is adopted on a three-year cycle — with intervening supplements — and local jurisdictions may add amendments, the exact requirements for your project depend on the edition your city or county has adopted and any local changes, which is exactly what GoCodebook reconciles for you.

Most CBC questions come down to four decisions made early in design: what occupancy group the building is, what type of construction it uses, whether it is sprinklered, and how far occupants have to travel to an exit. Those four answers drive allowable height and area, required fire-resistance ratings, and the number and width of exits — so a change to any of them ripples through the whole set. The chapter list further down opens the adopted text for each of them.

The CBC sets minimum standards for life safety and structural integrity. Core areas include occupancy classification (Groups A, B, E, F, H, I, M, R, S and U), types of construction (Type I through Type V), allowable building height and area, fire-resistance-rated construction, means of egress, interior finishes, accessibility, and structural design loads.

Accessibility is addressed in Chapter 11A (covered multifamily housing, enforced by HCD) and Chapter 11B (public accommodations and commercial facilities, written by the Division of the State Architect). California accessibility requirements are enforced statewide as building code — not just as civil-rights law — and in some cases are stricter than the federal ADA Standards.

The CBC also carries provisions that only apply to specific building types and enforcing agencies: hospitals and clinics under HCAI (formerly OSHPD), public schools and community colleges under DSA, and local detention facilities under BSCC. Those appear as bracketed agency banners in the text — a section marked [DSA-SS] does not apply to a private office building.

Occupancy classification assigns a building or space to a group based on how it is used: A assembly, B business, E educational, F factory, H high-hazard, I institutional, M mercantile, R residential, S storage and U utility. Apartments and most multifamily buildings are Group R-2; hotels are R-1; a restaurant over 49 occupants is typically A-2. Buildings with more than one use are resolved under Section 508 as accessory, non-separated or separated occupancies.

Type of construction describes what the building is made of and how well its structural frame is protected: Type I and II are noncombustible, Type III has noncombustible exterior walls with combustible interior framing, Type IV is heavy timber and mass timber, and Type V is any material permitted by the code — in practice, wood frame. Each type carries a required fire-resistance rating table in Chapter 6.

Put together, occupancy group plus construction type plus sprinkler status determine the allowable height in feet, allowable number of stories, and allowable area per floor. This is why a five-over-two podium building is Type IIIA or VA over Type IA, and why adding an NFPA 13 sprinkler system can buy an extra story and a substantial area increase.

Chapter 10 governs the entire egress path — exit access, exit, and exit discharge. The calculation starts with occupant load (Section 1004), which is derived from floor area and an occupant-load factor per use. Occupant load then determines how many exits a space or story needs (Section 1006), how wide those exits and the corridors serving them must be (Section 1005), and when panic hardware and two separated exits become mandatory.

Exit access travel distance (Section 1017) caps how far an occupant can walk to reach an exit, and the limit increases in sprinklered buildings. Common corrections in plan check come from Section 1010 (door swing, clear width, hardware and thresholds), Section 1011 (stair riser and tread geometry, headroom, landings), Section 1014 (handrail height and extensions), and Section 1015 (guard height and the 4-inch sphere rule at openings).

Egress and accessibility interact: accessible means of egress (Section 1009) requires areas of refuge or an elevator meeting specific criteria in certain buildings, and Chapter 11B adds its own requirements for the accessible route that leads to those exits.

Chapter 7 defines fire walls, fire barriers, fire partitions, smoke barriers and horizontal assemblies, along with the rating each needs and how penetrations, joints and ducts through them must be protected. Section 705 sets fire-resistance and opening-protection requirements for exterior walls based on fire separation distance — the single most common source of corrections on infill and small-lot projects, because it is driven by the distance to the property line.

Chapter 9 covers active systems: automatic sprinkler systems (Section 903), standpipes (905), fire alarm and detection (907), smoke control (909), carbon monoxide detection (915) and emergency responder radio coverage (918). The thresholds that trigger sprinklers are occupancy-specific — a Group R building generally requires sprinklers throughout regardless of size.

The CBC and the California Fire Code (CFC, Part 9) are written to be used together and share section numbering in Chapter 9. The CBC governs what gets built; the CFC governs what must be maintained and how the building is operated. Where a local fire department has adopted amendments, those usually land in the CFC rather than the CBC.

Use the CBC for commercial buildings, multifamily apartments and condominiums, and most non-residential occupancies. Use the California Residential Code (CRC, Part 2.5) for detached one- and two-family dwellings and townhouses up to three stories. ADU and small-lot projects can fall under either depending on configuration — a common source of confusion that drives plan-check corrections.

The boundary matters because the two codes reach different answers for the same building. A three-story townhouse designed under the CRC uses prescriptive bracing tables; the same building pushed into the CBC needs an engineered lateral design, a fire-resistance-rated separation strategy, and Chapter 11A accessibility review. Duplexes, triplexes and small SB 9 projects sit right on that line.

A single project usually triggers several Title 24 parts at once: the CBC plus the Electrical, Mechanical, Plumbing, Energy, Fire and CALGreen codes. Work in an existing building adds the California Existing Building Code (CEBC, Part 10).

The Building Standards Commission publishes Title 24, and the CBC incorporates amendments from agencies such as HCD, DSA and HCAI (formerly OSHPD). Cities and counties then adopt the code and may add local amendments for climate, geology or fire-hazard reasons, supported by findings filed with the state. That means the controlling text for a setback, fire rating or egress question can differ between two neighboring jurisdictions.

Local amendments cluster in predictable places: roof-covering class in very-high fire hazard severity zones, sprinkler thresholds lower than the state minimum, seismic retrofit ordinances for soft-story and non-ductile concrete buildings, and expiration or extension of permits. San Francisco, Los Angeles, San Jose, Oakland and Berkeley all amend the CBC in ways that change common details.

GoCodebook identifies the adopted edition and local amendments for your address and returns the governing provision with a citation, so you can verify the original language quickly. See where coverage is deepest, or start from a city page to read local code alongside the state text.

California's adopted codes — including the California Building Code (CBC) — are published under Title 24 and hosted on code libraries such as UpCodes (up.codes) and ICC Digital Codes from the International Code Council (ICC). Those let you read the text section by section.

GoCodebook goes further: instead of searching a code library, you ask a question and get the controlling provision for the edition and local amendments your jurisdiction adopted, with a citation to verify. See how GoCodebook compares to UpCodes and ICC.