CBC Chapter 7A: Wildfire Resistance
Materials and construction methods for buildings in Wildland-Urban Interface zones
Last updated: April 10, 2026
Overview
2025 code cycle update: The 2025 California Building Standards Code (Title 24) was published July 1, 2025 and took effect January 1, 2026. As part of this cycle, the Building Standards Commission deleted Chapter 7A from the California Building Code and relocated its requirements into the new California Wildland-Urban Interface Code (CWUIC), Title 24 Part 7. CBC Chapter 7A now contains only a placeholder pointing readers to CBC Section 101.4.8 and to the CWUIC. The substantive material standards for exterior wildfire exposure live in CWUIC Chapter 5.
California Building Code Chapter 7A established minimum standards for materials and construction methods for buildings in Wildland-Urban Interface (WUI) Fire Areas and Fire Hazard Severity Zones. The intent has not changed under the new CWUIC: structures in mapped fire hazard areas must be built with components that resist ignition from radiant heat, direct flame contact, and wind-driven embers.
The new CWUIC consolidates rules that were previously scattered across CBC Chapter 7A, California Residential Code Section R337, and California Fire Code Chapter 49. It is modeled on the International Wildland-Urban Interface Code and includes a cross-reference tool that maps each provision back to its original source. For projects designed under the 2022 CBC, the Chapter 7A technical content carries forward almost unchanged into CWUIC Chapter 5. The main difference is where you look it up.
Who this applies to: Wildfire construction requirements are mandatory in State Responsibility Area (SRA) lands classified Moderate, High, or Very High Fire Hazard Severity Zone, and in Local Responsibility Area (LRA) Very High Fire Hazard Severity Zones. CAL FIRE adopted updated SRA maps effective April 1, 2024 and released the LRA Phase 1 through 4 recommended maps between February and March 2025, expanding the footprint in many counties. Confirm your parcel's current zone with the local building department before relying on older maps.
The code addresses exterior components most vulnerable to wildfire: roofing, siding, exterior walls, windows, decks, soffits, and vents. These provisions work alongside defensible space and home hardening requirements to create ignition-resistant structures.
Key Requirements
- Ignition-resistant or noncombustible materials for exterior components
- Ember-resistant vents with 1/16" to 1/8" mesh screening
- Class A fire-rated roofing assemblies
- Tempered glass windows and doors
- 6-foot clearance zones around structures
Frequently Asked Questions
Is CBC Chapter 7A still in effect under the 2025 California Building Code?
The technical requirements are still in effect, but they have been moved. Under the 2025 Title 24 cycle (effective January 1, 2026), the Building Standards Commission deleted Chapter 7A from the California Building Code and relocated all of its provisions into the new California Wildland-Urban Interface Code (CWUIC), Title 24 Part 7. CBC Chapter 7A now contains only a placeholder pointing to CBC Section 101.4.8 and to the CWUIC. The construction standards themselves carry forward almost unchanged.
Does CBC Chapter 7A apply to my property?
The wildfire construction rules apply if your parcel sits inside a mapped Fire Hazard Severity Zone or designated Wildland-Urban Interface area. In State Responsibility Area lands, that includes Moderate, High, and Very High zones. In Local Responsibility Area lands, the Very High zone is the mandatory trigger, and many local jurisdictions enforce additional zones by ordinance. The fastest way to find out is to enter your address in the CAL FIRE Fire Hazard Severity Zone viewer or call your local building department.
What is a Fire Hazard Severity Zone?
Fire Hazard Severity Zones (FHSZ) are areas the State Fire Marshal classifies as Moderate, High, or Very High based on a hazard model that considers fuel type, terrain, fire history, ember exposure, and typical fire weather. CAL FIRE maintains separate map sets for State Responsibility Area lands (where the state funds wildfire protection) and Local Responsibility Area lands (where cities and counties take the lead). The current SRA maps were adopted effective April 1, 2024, and the LRA recommended maps were released in four phases between February and March 2025.
What is the difference between CBC Chapter 7A and CBC Chapter 7?
CBC Chapter 7 covers fire and smoke protection features that apply to buildings generally, things like fire-resistance-rated walls, floor assemblies, opening protectives, and fire stopping inside the structure. Chapter 7A (and now CWUIC Chapter 5) is narrower: it deals only with the exterior envelope and how it resists wildfire exposure from outside. A building in a fire hazard zone has to meet both. Chapter 7 protects occupants from a fire that starts inside; the wildfire provisions protect the building from a fire approaching from the outside.
Which materials are approved for wildfire-zone construction?
The code does not maintain a single approved-products list. Instead, it sets performance requirements for each component (roof, exterior wall, siding, eaves, soffits, vents, decks, windows, doors) and defines the test methods a product must pass to qualify. Roof coverings need a Class A rating. Exterior walls and siding must be either noncombustible or qualify as ignition resistant. Vents must resist ember intrusion under a referenced test standard. Manufacturers publish listings showing which of their assemblies meet each requirement, and the State Fire Marshal also maintains a Building Materials Listing program for products tested to California methods.
Do I need to retrofit an existing home in a Fire Hazard Severity Zone?
The wildfire construction provisions apply to new buildings, additions, and qualifying alterations or repairs. They are not a blanket retrofit mandate for existing homes. However, if you replace a roof, residing the building, or do significant remodeling, the work that you touch generally has to meet current standards. California also has separate defensible space and home hardening rules that apply to existing homes in high-risk zones, including vegetation management within 100 feet of the structure. Your local fire authority can confirm what triggers a code-compliant upgrade on your project.
What are the vent screening requirements for a wildfire zone?
Attic, eave, and underfloor vents in a fire hazard zone must resist ember and flame intrusion. The simplest path is corrosion-resistant metal mesh with openings no larger than 1/8 inch and no smaller than 1/16 inch. Engineered ember-resistant vents tested to the referenced California test method (and listed by the State Fire Marshal) are also accepted, and they perform better in real wind-driven ember exposure. See the soffits and vents page below for the specific assemblies and listed product families.
Who enforces CBC Chapter 7A and the CWUIC?
Enforcement runs through the local building department on plan review and field inspection, the same way the rest of the building code is enforced. In State Responsibility Area lands, CAL FIRE can also be involved on defensible space and on projects within their jurisdiction. Submit listings and test reports for any wildfire-rated components with your permit set, and expect the inspector to verify installed products against approved submittals before sign-off.
CBC Chapter 7A Compliant Products
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