Key Updates in the 2025 California Building Code (CBC)

By Steven Dannaway, PE, DBIA | Managing Principal, Fire Protection Engineering, Los Angeles

This article highlights several notable changes in the 2025 California Building Code (CBC) which will be effective January 1, 2026. While not exhaustive, it provides an overview of key updates. For further guidance on changes to the California Building Standards Code, please contact Coffman.

1. Wildland-Urban Interface (WUI) Code: The International Code Council (ICC) created a new Wildland-Urban Interface (WUI) code aimed at reducing the risk of wildfires. California has repealed CBC Chapter 7A and adopted the new WUI code, incorporating prior California amendments.

2. High-Rise Classification: The measurement to determine a high-rise building now includes the elevation of any occupied roof. In prior codes, the high-rise measurement was taken to the highest occupied floor, and occupied roofs were not a factor. Further reading: Is my building a high-rise?

3. Two-Way Communication Systems – Stairways & Elevators: Stairway two-way communication systems (when stair doors are locked from stair side) and elevator lobby two-way communication systems must comply with NFPA 72. This was not a clear requirement in previous codes. NFPA 72 (2025 edition) contains clear requirements addressing these systems.

4. Horizontal Exit Communication Systems: CBC 1026.6 now requires two-way communication systems at horizontal exits, on each side of the horizontal exit that does not have an elevator lobby with a two-way communication system.

5. Stairway Exterior Wall Protection: CBC 1023.7.2 is a new requirement that builds on the 180-degree rule for protection of stairway exterior walls. If a stairway extends above a low roof, the new code either requires one-hour protection of the stairway exterior wall for 10 ft above the roof surface or requires the roof to be one-hour rated with 45-minute rated openings within 10 ft of the stairway exterior wall. This requirement does not apply at the true high-roof condition where the stair penthouse is extending above the roof.

6. Egress Court Fire Separation Exception: A new exception in CBC 1029.3 relaxes requirements for fire separation of an egress court that is less than 10 ft in width and less than 10 ft away from the building. If an occupant can travel in two different directions in the egress court to two separate paths towards the public way, there is no requirement for the fire separation between the egress court and the building.

7. Insulated Metal Panels: CBC 1409 is a new code section added in Chapter 14 that addresses requirements for insulated metal panels. The CBC Chapter 2 definition is: “A factory manufactured panel consisting of metal facings and an insulation core intended for use as a system forming an exterior wall, an exterior wall covering, a roof covering, or a roof assembly of a building.”

8. Podium Construction Updates: There are two changes to podium construction involving a three-hour horizontal assembly that separates two different types of construction (CBC 510.2):

• Group A occupancies with an occupant load > 300 are now allowed above the three-hour horizontal building separation.
• Vertical offsets of the three-hour horizontal building separation are to be constructed as fire barriers.

9. Exterior Wall Continuity: CBC Section 705 contains new requirements that address continuity of fire-resistance rated exterior walls and how the exterior wall continuity is affected by intersecting floor assemblies or roof assemblies.

10. Floor Penetration Exceptions: There are two new exceptions for floor penetrations.

• CBC 714.5.1 Exception 4 now allows unprotected penetrations of concrete floors within parking garages (open or enclosed), when the areas above and below the penetrations are parking garage areas.
• CBC 714.5.1.2 Exception 4 now exempts the T-rating requirement where penetrations are protected with concrete, grout, and mortar and aligns the code for situations where the F-rating was exempted by CBC 714.5.1 for the same protection method at floor penetrations.

For more details or project-specific guidance, contact us. We’re here to help you navigate code updates.