Wall Assembly Requirements Between an ADU and a Garage in California

By S. N. • Published 10/19/2025

When an **Accessory Dwelling Unit (ADU)** shares a wall or ceiling with a **garage**, that separation must provide adequate **fire protection** between the habitable space and the area used for vehicle storage. The rules come from the **2025 California Residential Code (CRC)** and the **2025 California Building Code (CBC)**, which apply to all **R-3 Occupancy, Type VB** residential construction.