2025 California Building Code — Key Changes Every Architect and Engineer Should Know

By Sunwoo Kim • Published 11/17/2025

The 2025 California Building Code (CBC) brings some of the most sweeping technical and organizational updates in a decade. Based on the 2024 International Building Code, this new edition modernizes California’s approach to mass timber, seismic safety, fire protection, wildfire resilience, and building coordination across the state’s evolving regulatory framework. Here’s what you need to know before the new code takes effect on January 1, 2026.