What does a new home or ADU in a fire hazard zone have to include?
New homes and ADUs in these zones follow the 2025 California Wildland-Urban Interface Code (Title 24, Part 7), which replaced the old Building Code Chapter 7A. It requires a Class A roof, vents listed to ASTM E2886 or covered with 1/16 to 1/8 in mesh, multi-pane windows with at least one tempered pane, and noncombustible gutters.
The hazard zone, the department that inspects, past fires nearby and every rule that applies to your home.
The main requirements
- Roof
- Class A fire classification.
- Vents
- Listed to ASTM E2886, or covered with mesh with openings from 1/16 in to 1/8 in.
- Windows
- Multi-pane units with at least one tempered pane.
- Gutters
- Noncombustible.
- Small sheds
- Accessory structures of 120 sq ft or less are exempt.
ADUs
A detached ADU is a new building, so it meets these rules in full. Before you buy a pre-approved plan for a very high zone, ask the firm whether the design meets the Wildland-Urban Interface Code as drawn.
Sources
- LA County Public Works, very high fire hazard severity zone notes, 2026 code version, read November 9, 2026
General information, not legal advice. Your fire department and city have the final word for your property.
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