CRC · California Residential Code
Are there special venting rules for Wildland‑Urban Interface (WUI) areas?
If your home is in a designated Wildland‑Urban Interface or Fire Hazard Severity Zone, any attic, soffit, crawl space or foundation vents you provide must not only meet the usual CRC sizing rules but must be ember‑ and flame‑resistant and installed using WUI‑approved products and methods — the CRC **§ R806.1.1** directs you to the California Wildland‑Urban Interface Code (Part 7) for those protective requirements.
Last reviewed: July 6, 2026
What the code requires — plain English
If a building is in a Wildland‑Urban Interface (WUI) or applicable Fire Hazard Severity Zone, any ventilation opening (attic, eave/soffit, gable, ridge, underfloor, crawl space, foundation, etc.) that is provided must meet the ember‑ and flame‑resistance requirements in the California Wildland‑Urban Interface Code (Part 7) rather than only the ordinary CRC venting rules. See § R806.1.1 for the controlling direction to follow Part 7.
The single most important rule: if your house is in a designated WUI area or fire‑hazard zone, any ventilation openings you provide must be designed and installed to resist ember and flame entry in accordance with the California Wildland‑Urban Interface Code (Part 7). § R806.1.1.
Requirements in detail
1) Scope — which openings are affected
- All ventilation openings for: enclosed attics, gable ends, ridge ends, under eaves and cornices, enclosed eave soffit spaces, enclosed rafter spaces, underfloor ventilation, foundations, crawl spaces, or any opening intended to permit ventilation. This list is explicit in § R806.1.1.
- The CRC does not replace Part 7; it directs that vent design and protection in WUI areas be done in accordance with the California Wildland‑Urban Interface Code (Part 7). § R806.1.1.
2) What “in accordance with Part 7” means in practice
- Part 7 contains the WUI product, installation and construction regulations (Chapter 5 and referenced standards) that require ember‑ and flame‑resistant vents or approved WUI‑labeled products. See Part 7 (California Wildland‑Urban Interface Code) for the detailed product and installation standards.
- The WUI Code recommends (and Part 7 makes enforceable when adopted) the use of ember‑ and flame‑resistant vents and OSFM‑approved WUI products; Appendix guidance also suggests mesh openings and product labeling to resist ember intrusion.
3) How this interacts with ordinary CRC vent sizing and installation rules
- The CRC still contains its general venting rules (e.g., minimum net free venting area and screen dimension guidance) but R806.1.1 redirects the protective requirements for vents in WUI areas to Part 7. For example:
- CRC minimum net free vent area: 1/150 of vented space (exception 1/300 under specified conditions) — § R806.2.
- CRC screening least dimension guidance for general vents: 1/16 inch minimum to 1/4 inch maximum (screening required if openings larger than 1/4 inch) — § R806.1.
- However, where the building is in the WUI, the protective (ember/flame) performance of the vent is not satisfied merely by the CRC’s generic screen-size language — it must meet the WUI Code requirements in Part 7. § R806.1.1.
Decision‑relevant dimensions and values
| Decision item | Typical values / testable attribute | Code Reference |
|---|---|---|
| Direction to follow WUI rules for vents | Use Part 7 (California Wildland‑Urban Interface Code) for ventilation openings in WUI areas | § R806.1.1 |
| CRC general screen opening guidance (non‑WUI) | Vent openings: 1/16" min — 1/4" max; openings larger than 1/4" require corrosion‑resistant mesh sized 1/16"–1/4" | § R806.1 |
| Minimum net free ventilating area (when vents are provided) | 1/150 of vented space (Exception: 1/300 when specific vapor retarder and upper vent % conditions are met) | § R806.2 |
| WUI vent product guidance | Use ember‑ and flame‑resistant vents; choose products labeled/approved for WUI (OSFM WUI product listings) | Part 7 and Appendix guidance in the California Wildland‑Urban Interface Code |
| Applicability trigger (which buildings must comply with Part 7) | New buildings located in any Fire Hazard Severity Zone or WUI Fire Area as designated by enforcing agency (see Part 7 § 101.3.1) | § 101.3.1 (California Wildland‑Urban Interface Code) |
Exceptions & special cases
- The CRC language in § R806.1.1 is written as “Where provided… shall be in accordance with Part 7,” so:
- If the jurisdiction has adopted the California Wildland‑Urban Interface Code and the building falls within a WUI/Fire Hazard Severity Zone, the Part 7 vent requirements apply. See § 101.3.1 in the WUI Code for scope and application.
- Some accessory structures and small Group U buildings may be excepted from parts of the WUI Code (check Part 7 exceptions such as accessory structures separated by required distances). See Part 7 exceptions for applicability.
- Unvented attic / unvented enclosed rafter assemblies: CRC provides a path to unvented attics § R806.5 (conditions apply). If you choose an unvented assembly, the WUI vent‑opening rules are not applicable for vents you are not providing — but the rest of the WUI construction/protection requirements remain applicable where they apply. § R806.5 and § R806.1.1.
Common mistakes
- Assuming standard attic screening (e.g., basic 1/4" hardware cloth) automatically complies in a WUI zone. The CRC redirects you to Part 7 for ember/flame resistance — use tested/approved WUI vents or OSFM‑listed products. § R806.1.1; Part 7 guidance.
- Designing to CRC ventilation area numbers (1/150 or 1/300) but forgetting to specify WUI‑rated vent products when the site is in a WUI area. Sizing and ember protection are separate requirements; you must satisfy both where applicable. § R806.2 and § R806.1.1.
- Plugging or permanently closing vents without providing an approved unvented attic assembly. If vents are removed, ensure compliance with the unvented attic rules § R806.5, and still comply with any WUI requirements that apply to the alternative assembly.
- Forgetting to verify whether the jurisdiction has adopted the California Wildland‑Urban Interface Code and which parts (the WUI Code contains adoption exceptions and application dates). Check local adoption and the code official’s interpretation (Part 7 § 101.3.1).
Worked example — attic ventilation in a WUI‑designated area
Scenario:
- New single‑family house in a designated WUI / Very High Fire Hazard Severity Zone.
- Vented attic floor area = 1,500 sq ft.
- You plan to provide vents (not an unvented attic).
Steps:
- Determine sizing per CRC vent area rules:
- Minimum net free ventilating area = 1/150 of vented space = 1,500 / 150 = 10.0 sq ft net free area (NFA). § R806.2.
- (If you met the exception conditions you could use 1/300; but that has other requirements — see § R806.2.)
- Choose vent locations and products:
- Provide balanced low and high vents per CRC guidance (and manufacturer instructions) so air flows; but because the site is in a WUI area, each vent opening must meet Part 7 ember/flame resistance requirements — do not rely solely on a standard 1/4" screen. § R806.1.1 and Part 7.
- Select vent product and verify labeling:
- Use vents listed as OSFM WUI or otherwise approved for WUI use, or use assembly details in Part 7 that demonstrate ember/flame protection (e.g., tested mesh or proprietary ember‑resistant vents). Appendix guidance recommends mesh in the 1/16"–1/8" range or approved WUI vents as temporary/retrofit options; prefer OSFM‑approved products.
- Install to achieve required NFA:
- If a chosen WUI vent has, for example, 10 in² net free area per unit, you need 10.0 sq ft × 144 in²/sq ft = 1,440 in² total NFA → 1,440 / 10 = 144 vents (or 72 pairs distributed high/low) — or choose fewer vents with larger NFA per unit. Ensure the installed net free area is the sum of the manufacturer’s listed NFA for the WUI‑rated product. Also verify the vent installation meets manufacturer and Part 7 installation requirements. § R806.2 and § R806.1.1.
Notes: the numeric example uses CRC sizing math (R806.2) but the product selection and screening/mesh must comply with Part 7 WUI product/installation rules per § R806.1.1.
Related provisions
- § R806.1 — General venting openings, screening dimensions and protection for typical (non‑WUI) installations.
- § R806.1.1 — Vents in the Wildland‑Urban Interface (primary controlling direction: follow Part 7).
- § R806.2 — Minimum net free ventilating area (1/150; exception 1/300).
- § R806.5 — Unvented attics and enclosed rafter assemblies (conditions when allowed).
- California Wildland‑Urban Interface Code (Part 7): § 101.3.1 — Application (which new buildings/areas must comply) and Chapter 5 (Special Building Construction Regulations) for vent/product requirements.
- California Wildland‑Urban Interface Code — Appendix/Guidance on WUI products and ember‑resistant vent recommendations (see Appendix and Chapter 7 referenced standards).
Code references
Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:
CRC § 1.1 High relevance — show source text
Openings in roof framing members shall conform to the requirements of Section R802.7. Required ventilation openings shall open directly to the outside air and shall be protected to prevent the entry of birds, rodents, snakes and other similar creatures.
R806.1.1 Vents in the Wildland Urban Interface (WUI). Where provided, ventilation openings for enclosed attics, gable ends, ridge ends, under eaves and cornices, enclosed eave soffit spaces, enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters, underfloor ventilation, foundations and crawl spaces, or any other opening intended to permit ventilation, either in a horizontal or vertical plane, shall be in accordance with Part 7, California Wildland-Urban Interface Code to resist building ignition from the intrusion of burning embers and flame through the ventilation openings. R806.2 Minimum vent area. The minimum net free ventilating area shall be [1] / 150 of the area of the vented space. Exception: The minimum net free ventilation area shall be [1] / 300 of the vented space provided both of the following conditions are met:
- In Climate Zones 6, 7 and 8, a Class I or II vapor retarder is installed on the warm-in-winter side of the ceiling.
- Not less than 40 percent and not more than 50 percent of the required ventilating area is provided by ventilators located in the upper portion of the attic or rafter space. Upper ventilators shall be located not more than 3 feet (914 mm) below the ridge or highest point of the space, measured vertically. The balance of the required ventilation provided shall be located in the bottom one-third of the attic space. Where the location of wall or roof framing members conflicts with the installation of upper ventilators, installation more than 3 feet (914 mm) below the ridge or highest point of the space shall be permitted.
R806.3 Vent and insulation clearance. Where eave or cornice vents are installed, blocking, bridging and insulation shall not block the free flow of air. Not less than a 1-inch (25 mm) space shall be provided between the insulation and the roof sheathing and at the location of the vent.
R806.4 Installation and weather protection. Ventilators shall be installed in accordance with manufacturer’s instructions. Installation of ventilators in roof systems shall be in accordance with the requirements of Section R903. Installation of ventilators in wall systems shall be in accordance with the requirements of Section R703.1.
R806.5 Unvented attic and unvented enclosed rafter assemblies. Unvented attics and unvented enclosed roof framing assemblies created by ceilings that are applied directly to the underside of the roof framing members and structural roof sheathing applied directly to the top of the roof framing members/rafters, shall be permitted where all the following conditions are met:
- The unvented attic space is completely within the building thermal envelope.
- Interior Class I vapor retarders are not installed on the ceiling side (attic floor) of the unvented attic assembly or on the ceiling side of the unvented enclosed roof framing assembly.
- Where wood shingles or shakes are used, a minimum [1] / 4 -inch (6.4 mm) vented airspace separates the shingles or shakes and the roofing underlayment above the structural sheathing.
CRC § 101.3.1 High relevance — show source text
This code shall supplement the jurisdiction’s building and fire codes, if such codes have been adopted, to provide for special regulations to mitigate the fire- and life-safety hazards of the wildland-urban interface areas.
101.3.1 Application. New buildings located in any Fire Hazard Severity Zone or Wildland-Urban Interface (WUI) Fire Area designated by the enforcing agency constructed after the application date shall comply with the provisions of this code. This shall include all new buildings with residential, commercial, educational, institutional or similar occupancy type use, which shall be referred to in this code as “applicable buildings,” as well as new buildings and structures accessory to those applicable buildings.
Exceptions: 1. Group U occupancy accessory buildings of any size located at least 50 feet (15 240 mm) from an applicable building on the same lot.
2. Group U occupancy agricultural buildings, as defined in Section 202 of the California Building Code of any size located at least 50 feet (15 240 mm) from an applicable building. 3. Group C occupancy special buildings conforming to the limitations specified in Section 450.4.1 of the California Building Code. 4. New accessory buildings and miscellaneous structures specified in Section 504.11 shall comply only with the requirements of that section.
5. Additions to and remodels of buildings originally constructed prior to July 1, 2008.
101.3.1.1 Application date and where required. New buildings for which an application for a building permit is submitted on or after July 1, 2008, located in any Fire Hazard Severity Zone or Wildland-Urban Interface Area shall comply with this code, including all of the following areas:
All unincorporated lands designated by the State Board of Forestry and Fire Protection as State Responsibility Area (SRA) including:
Moderate Fire Hazard Severity Zones.
High Fire Hazard Severity Zones.
Very High Fire Hazard Severity Zones.
Land designated as a Very High Fire Hazard Severity Zone by cities and other local agencies.
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 1-15
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ADMINISTRATION
Land designated as a wildland-urban interface area by cities and other local agencies.
Exceptions: 1. New buildings located in any Fire Hazard Severity Zone within a State Responsibility Area, for which an application for a building permit is submitted on or after January 1, 2008, shall comply with this code. 2. New buildings located in any Fire Hazard Severity Zone within a State Responsibility Area or any wildland-urban interface area designated by cities and other local agencies for which an application for a building permit is submit- ted on or after December 1, 2005, but prior to July 1, 2008, shall only comply with the following sections of this chapter: 2.1. Section 507 – Replacement or Repair of Roof Coverings.
2.2. Section 504.10 – Vents.
[A] 101.4 Retroactivity. The provisions of the code shall apply to conditions arising after the adoption thereof, conditions not legally in existence at the adoption of this code and conditions that, in the opinion of the code official, constitute a distinct hazard to life or property.
Exception: Provisions of this code that specifically apply to existing conditions are retroactive.
CRC § 3.8 High relevance — show source text
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ROOF-CEILING CONSTRUCTION
R804.3.8 Roof tie-down. Roof assemblies shall be connected to walls below in accordance with Table R804.3. A continuous load path shall be provided to transfer uplift loads to the foundation.
SECTION R805—CEILING FINISHES
R805.1 Ceiling installation. Ceilings shall be installed in accordance with the requirements for interior wall finishes as provided in Sections R702.1 through R702.6.
SECTION R806—ROOF VENTILATION
Note: The IECC climate zones used by this section differ from those used by the California Energy Code to determine applicability of energy efficiency measures. Comparison of IECC and California Energy Code climate zones is shown in Table R702.7.3.
R806.1 Ventilation required. Enclosed attics and enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters shall have cross ventilation for each separate space by ventilating openings protected against the entrance of rain or snow. Ventilation openings shall have a least dimension of [1] / 16 inch (1.6 mm) minimum and [1] / 4 inch (6.4 mm) maximum. Ventilation openings having a least dimension larger than [1] / 4 inch (6.4 mm) shall be provided with corrosion-resistant wire cloth screening, hardware cloth, perforated vinyl or similar material with openings having a least dimension of [1] / 16 inch (1.6 mm) minimum and [1] / 4 inch (6.4 mm) maximum. Openings in roof framing members shall conform to the requirements of Section R802.7. Required ventilation openings shall open directly to the outside air and shall be protected to prevent the entry of birds, rodents, snakes and other similar creatures.
R806.1.1 Vents in the Wildland Urban Interface (WUI). Where provided, ventilation openings for enclosed attics, gable ends, ridge ends, under eaves and cornices, enclosed eave soffit spaces, enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters, underfloor ventilation, foundations and crawl spaces, or any other opening intended to permit ventilation, either in a horizontal or vertical plane, shall be in accordance with Part 7, California Wildland-Urban Interface Code to resist building ignition from the intrusion of burning embers and flame through the ventilation openings. R806.2 Minimum vent area. The minimum net free ventilating area shall be [1] / 150 of the area of the vented space. Exception: The minimum net free ventilation area shall be [1] / 300 of the vented space provided both of the following conditions are met:
- In Climate Zones 6, 7 and 8, a Class I or II vapor retarder is installed on the warm-in-winter side of the ceiling.
- Not less than 40 percent and not more than 50 percent of the required ventilating area is provided by ventilators located in the upper portion of the attic or rafter space. Upper ventilators shall be located not more than 3 feet (914 mm) below the ridge or highest point of the space, measured vertically. The balance of the required ventilation provided shall be located in the bottom one-third of the attic space.
CRC § 1.5 High relevance — show source text
[California Code of Regulations, Title 14, Division 1.5, §1270.08] Distance Measurements.
All specified or referenced distances are measured along the ground unless otherwise stated.
1.12.2 Agency identification. The provisions of this code applicable to wildland-urban interface areas identified in Section 1.12 are identified in the body of the code by square brackets containing references to applicable Title 14 sections and in the Cross Reference Table located in Appendix H, Section H107.
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DIVISION II
SCOPE AND ADMINISTRATION
User notes:
About this chapter: Chapter 1 establishes the limits of applicability of the code and describes how the code is to be applied and enforced. Chapter 1 is in two parts: Part 1–General Provisions (Sections 101–102) and Part 2—Administration and Enforcement (Sections 103–113). Section 101 identifies which buildings and structures come under its purview and references other California Codes as applicable.
This code is intended to be adopted as a legally enforceable document and it cannot be effective without adequate provisions for its administration and enforcement. The provisions of Chapter 1 establish the authority and duties of the code official appointed by the authority having jurisdiction and also establish the rights and privileges of the design professional, contractor and property owner.
Note: Sections adopted or amended by state agencies are specifically indicated by an agency banner or indicated in the Matrix Adoption Table.
PART 1—GENERAL PROVISIONS
SECTION 101—SCOPE AND GENERAL REQUIREMENTS
[A] 101.1 Title. These regulations shall be known as the California Wildland-Urban Interface Code of [ NAME OF JURISDICTION ], hereinafter referred to as “this code.”
[A] 101.2 Scope. This code applies to building materials, systems and/or assemblies used in the exterior design and construction of new buildings located within a wildland-urban interface (WUI) area and contains minimum requirements to mitigate conditions that might cause a fire originating in a structure to ignite vegetation in the wildland-urban interface (WUI) area, and conversely, a wildfire burning in vegetative fuels to transmit fire to buildings and threaten to destroy life, overwhelm fire suppression capabilities or result in large property losses.
[A] 101.2.1 Appendices. Provisions in the appendices shall not apply unless specifically adopted.
[A] 101.3 Purpose. The purpose of this code is to establish minimum regulations for the safeguarding of life and for property protection. Regulations in this code are intended to mitigate the risk to life and structures from intrusion of fire from wildland fire exposures and fire exposures from adjacent structures and to mitigate structure fires from spreading to wildland fuels. The extent of this regulation is intended to be tiered commensurate with the relative level of hazard present.
The unrestricted use of property in wildland-urban interface areas is a potential threat to life and property from fire and resulting erosion. Safeguards to prevent the occurrence of fires and to provide adequate fire protection facilities to control the spread of fire in wildland-urban interface areas shall be in accordance with this code.
CRC § 6.1 High relevance — show source text
Exception: Places of habitation or in the boundaries of established smoking areas or campsites as designated by the code official.
A104.5 Equipment and devices generating heat, sparks or open flames. Equipment and devices generating heat, sparks or open flames capable of igniting nearby combustibles shall not be used in wildland-urban interface areas without a permit from the code official.
Exception: Use of approved equipment within inhabited premises or designated campsites that are not less than 30 feet (9144 mm) from grass-, grain-, brush- or forest-covered areas.
A104.6 Fireworks. Fireworks shall not be used or possessed in wildland-urban interface areas.
Exception: Fireworks allowed by the code official under permit in accordance with the California Fire Code where not prohibited by applicable local or state laws, ordinances and regulations.
A104.6.1 Authority to seize. The code official is authorized to seize, take, remove or cause to be removed fireworks in violation of this section.
A104.7 Outdoor fires. Outdoor fires in wildland-urban interface areas shall comply with Sections A104.7.1 through A104.7.3.
A104.7.1 General. Persons shall not build, ignite or maintain any outdoor fire of any kind for any purpose in or on any wildland- urban interface area, except by the authority of a written permit from the code official.
Exception: Outdoor fires within inhabited premises or designated campsites where such fires are in a permanent barbecue, portable barbecue, outdoor fireplace, incinerator or grill and are not less than 30 feet (9144 mm) from any combustible material or nonfire-smart vegetation.
A104.7.2 Permits. Permits shall incorporate such terms and conditions that will reasonably safeguard public safety and property. Outdoor fires shall not be built, ignited or maintained in or on hazardous fire areas under any of the following conditions:
- When high winds are blowing.
- When a person 17 years old or over is not present at all times to watch and tend such fire.
- When a public announcement is made that open burning is prohibited.
A104.7.3 Restrictions. Persons shall not use a permanent barbecue, portable barbecue, outdoor fireplace or grill for the disposal of rubbish, trash or combustible waste material.
A104.8 Incinerators, outdoor fireplaces, permanent barbecues and grills. Incinerators, outdoor fireplaces, permanent barbecues and grills shall not be built, installed or maintained in wildland-urban interface areas without approval of the code official.
A104.8.1 Maintenance. Incinerators, outdoor fireplaces, permanent barbecues and grills shall be maintained in good repair and in a safe condition at all times. Openings in such appliances shall be provided with an approved spark arrestor, screen or door.
Exception: Where approved by the code official, unprotected openings in barbecues and grills necessary for proper functioning.
A104.9 Reckless behavior. The code official is authorized to stop any actions of a person or persons if the official determines that the action is reckless and could result in an ignition of fire or spread of fire.
A104.10 Planting vegetation under or adjacent to energized electrical lines. Vegetation that, at maturity, would grow to within 10 feet (3048 mm) of the energized conductors shall not be planted under or adjacent to energized power lines.
SECTION A105—CONTROL OF STORAGE
CRC § 2.1 High relevance — show source text
G101.2.1 Home-hardening features. If homes are not already provided with the suggested protection, the following items should be considered in hardening a home against wildfire. 1. When it is time to replace your roof, replace it with roof assembly classified as Class A when tested in accordance with ASTM E108 or UL 790.
2. Block any spaces at the eaves between your roof covering and sheathing with noncombustible materials (bird stops). 3. Install a noncombustible rain gutter and downspouts. Install rain gutter covers to prevent the accumulation of leaves and debris in the gutters. 4. Cover your chimney and stovepipe outlets with a noncombustible, corrosion-resistant metal mesh screen (spark arrestor), with [3] / 8 -inch (9.5 mm) to [1] / 2 -inch (12.7 mm) openings. 5. Install ember- and flame-resistant vents. Choose products that have been approved and labeled as OSFM Wildland-Urban Interface (WUI) Products. A temporary solution is to cover the vent openings with a noncombustible and corrosion-resistant mesh with [1] / 16 -inch (1.6 mm) to [1] / 8 -inch (3.2 mm) openings. 6. Caulk and plug gaps greater than [1] / 8 inch (3.2 mm) around exposed rafters and blocking to prevent ember intrusion into the attic or other enclosed spaces. 7. Inspect exterior siding for dry rot, gaps, cracks and warping. Caulk or plug gaps greater than [1] / 8 inch (3.2 mm) in siding and replace any damaged boards, including those with dry rot. 8. Install weather stripping to fill gaps greater than [1] / 8 inch (3.2 mm) between garage doors and door frames to prevent ember intrusion. The weather stripping must be compliant with UL Standard 10C. 9. When it’s time to replace your windows, replace them with multipaned windows that have at least one pane of tempered glass. Choose products that have been approved and labeled as OSFM Wildland-Urban Interface (WUI) Products. 10. When it’s time to replace your siding or deck, use noncombustible, ignition-resistant, or other OSFM-approved Wildland- Urban Interface (WUI) Products. 11. Cover openings to operable skylights with noncombustible metal mesh screen with openings in the screen not to exceed [1] / 8 inch (3.2 mm). 12. Install a minimum 6-inch metal flashing, applied vertically on the exterior of the wall at the deck-to-wall intersection to protect the combustible siding material. 13. _Enclose openings beneath decks or cantilevered construction with one of the materials required in Section 504.5.
CRC § 7.3 Medium relevance — show source text
A104.7.3 Restrictions. Persons shall not use a permanent barbecue, portable barbecue, outdoor fireplace or grill for the disposal of rubbish, trash or combustible waste material.
A104.8 Incinerators, outdoor fireplaces, permanent barbecues and grills. Incinerators, outdoor fireplaces, permanent barbecues and grills shall not be built, installed or maintained in wildland-urban interface areas without approval of the code official.
A104.8.1 Maintenance. Incinerators, outdoor fireplaces, permanent barbecues and grills shall be maintained in good repair and in a safe condition at all times. Openings in such appliances shall be provided with an approved spark arrestor, screen or door.
Exception: Where approved by the code official, unprotected openings in barbecues and grills necessary for proper functioning.
A104.9 Reckless behavior. The code official is authorized to stop any actions of a person or persons if the official determines that the action is reckless and could result in an ignition of fire or spread of fire.
A104.10 Planting vegetation under or adjacent to energized electrical lines. Vegetation that, at maturity, would grow to within 10 feet (3048 mm) of the energized conductors shall not be planted under or adjacent to energized power lines.
SECTION A105—CONTROL OF STORAGE
A105.1 General. In addition to the requirements of the California Fire Code, storage and use of the materials shall be in accordance with Sections A105.2 through A105.4.2. A105.2 Hazardous materials. Hazardous materials in excess of 10 gallons (37.8 L) of liquid, 200 cubic feet (5.66 m [3] ) of gas, or 10 pounds (4.54 kg) of solids require a permit and shall comply with nationally recognized standards for storage and use.
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE APPENDIX A-5
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APPENDIX A—GENERAL REQUIREMENTS
A105.3 Explosives. Explosives shall not be possessed, kept, stored, sold, offered for sale, given away, used, discharged, transported or disposed of within wildland-urban interface areas, except by permit from the code official.
A105.4 Combustible materials. Outside storage of combustible materials such as, but not limited to, wood, rubber tires, building materials or paper products shall comply with the other applicable sections of this code and this section. A105.4.1 Individual piles. Individual piles shall not exceed 5,000 square feet (465 m [2] ) of contiguous area. Piles shall not exceed 50,000 cubic feet (1416 m [3] ) in volume or 10 feet (3048 mm) in height.
A105.4.2 Separation. A clear space of not less than 40 feet (12 192 mm) shall be provided between piles. The clear space shall not contain combustible material or nonfire-smart vegetation.
SECTION A106—DUMPING
A106.1 Waste material. Waste material shall not be placed, deposited or dumped in wildland-urban interface areas or in, on or along trails, roadways or highways or against structures in wildland-urban interface areas .
Exception: Approved public and approved private dumping areas.
CRC § 102.4 Medium relevance — show source text
The chapter includes mitigation strategies to reduce the hazards of fire originating within a structure spreading to wildland and fire originating in wildland spreading to structures.
Chapter 7 Referenced Standards.
Chapter 7 lists all of the product and installation standards and codes that are referenced throughout Chapters 1 through 6 and includes identification of the promulgators and the section numbers in which the standards and codes are referenced. As stated in Section 102.4, these standards and codes become an enforceable part of the code (to the prescribed extent of the reference) as if printed in the body of the code.
Appendix A General Requirements.
Appendix A, while not part of the code, can become part of the code when specifically included in the adopting ordinance. Its purpose is to provide fire-protection measures supplemental to those found in Chapter 6 to reduce the threat of wildfire in a wildland-urban interface area and improve the capability for controlling such fires. This appendix includes detailed requirements for vegetation control; the code official’s authority to close wildland-interface areas in times of high fire danger; control of fires, fireworks usage and other sources of ignition; storage of hazardous materials and combustibles; bans on the dumping of waste materials and ashes and coals in wildlandurban interface areas; protection of pumps and water supplies; and limits on temporary uses within the wildland-urban interface area.
Appendix B Vegetation Management Plan.
Appendix B, while not part of the code, can become part of the code when specifically included in the adopting ordinance. Its purpose is to provide criteria for submitting vegetation management plans, specifying their content and establishing a criterion for considering vegetation management as being a fuel modification.
Appendix C Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework.
Appendix C contains a preliminary Community WUI Fire Hazard Evaluation Framework as a suggested methodology to begin to support communities at risk in the identification of their unique hazards and to provide common metrics for comparisons between communities. This preliminary framework includes information on community size, population and fuels; on notification and evacuation; and on the community infrastructure and firefighting response potential. Aspects of this framework may already be included in various community- level documents, such as Community Wildfire Protection Plans or evacuation plans. Development of a standard framework will (1) consolidate relevant WUI fire hazard and planning information in one place, and (2) allow for cross-community comparisons.
The evaluation required to implement this framework will support prefire hazard assessment and during-fire response operations. An increased understanding of fire evacuation, fire structural response and fire defensive action relationships is needed to assess the over- all community WUI fire hazard. The quantification of these relationships will enable communities to optimize the community-level response to WUI fire hazards in a more integrated approach and result in increased life safety and reduced losses.
Appendix D Model Ordinance for Fire Hazard Severity Zone Adoption.
Appendix D is an informational appendix that is a sample ordinance designed as guidance for a city, county, city and county, or fire district to establish and designate fire hazard severity zones within their jurisdiction.
Appendix E Reserved.
Appendix F Characteristics of Fire-Smart Vegetation.
Appendix F is an informational appendix provided for the convenience of the code user. It is simply a compilation of the eight characteristics of fire-smart vegetation that can be used effectively within wildland-urban interface areas to reduce the likelihood of fire spread through vegetation.
**App
CRC § 102.4 Medium relevance — show source text
Chapter 5 Special Building Construction Regulations.
The regulations in Chapter 5 establish minimum standards for the location, design and construction of buildings and structures based on construction within a Fire Hazard Severity Zone or a Wildland-Urban Interface (WUI) Area.
The construction provisions of Chapter 5 are intended to supplement the requirements of the California Building Code and Califor- nia Residential Code and address mitigation of the unique hazards posed to buildings by wildfire and to reduce the hazards of building fires spreading to wildland fuels. This is accomplished by requiring ignition-resistant construction materials.
Chapter 6 Fire Protection Requirements.
Chapter 6 contains additional requirements for development and construction in Local Responsibility Areas (LRA) designated as Very High Fire Hazard Severity Zones and areas designated by the State Fire Marshal as State Responsibility Areas (SRA). While many of these provisions are found in Title 14 and Title 19 of the California Code of Regulations, they are replicated here for the code user. The local jurisdiction has the authority to apply the same regulations to LRA when the regulations are adopted by local ordinance.
The requirements in this chapter reference the process for adoption of Very High Fire Hazard Severity Zones in the LRA; criteria for evaluating existing subdivisions that are at significant fire risk and are without an adequate secondary egress; and criteria for fire safety provisions required in the Safety Element of a city or county General Plan.
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The chapter includes mitigation strategies to reduce the hazards of fire originating within a structure spreading to wildland and fire originating in wildland spreading to structures.
Chapter 7 Referenced Standards.
Chapter 7 lists all of the product and installation standards and codes that are referenced throughout Chapters 1 through 6 and includes identification of the promulgators and the section numbers in which the standards and codes are referenced. As stated in Section 102.4, these standards and codes become an enforceable part of the code (to the prescribed extent of the reference) as if printed in the body of the code.
Appendix A General Requirements.
Appendix A, while not part of the code, can become part of the code when specifically included in the adopting ordinance. Its purpose is to provide fire-protection measures supplemental to those found in Chapter 6 to reduce the threat of wildfire in a wildland-urban interface area and improve the capability for controlling such fires. This appendix includes detailed requirements for vegetation control; the code official’s authority to close wildland-interface areas in times of high fire danger; control of fires, fireworks usage and other sources of ignition; storage of hazardous materials and combustibles; bans on the dumping of waste materials and ashes and coals in wildlandurban interface areas; protection of pumps and water supplies; and limits on temporary uses within the wildland-urban interface area.
Appendix B Vegetation Management Plan.
Appendix B, while not part of the code, can become part of the code when specifically included in the adopting ordinance. Its purpose is to provide criteria for submitting vegetation management plans, specifying their content and establishing a criterion for considering vegetation management as being a fuel modification.
Appendix C Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework.
CRC § 5-1 Medium relevance — show source text
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5 SPECIAL BUILDING CONSTRUCTION REGULATIONS
User notes:
About this chapter: Chapter 5 provides regulations that establish minimum standards for the location, design and construction of buildings and structures based on construction within a Fire Hazard Severity Zone or a Wildland-Urban Interface (WUI) Area.
The construction provisions of Chapter 5 are intended to supplement the requirements of the California Building Code and California Residential Code and address mitigation of the unique hazards posed to buildings by wildfire and to reduce the hazards of building fires spreading to wildland fuels. This is accomplished by requiring ignition-resistant construction materials. Construction features regulated include underfloor areas; roof coverings; eaves and soffits; gutters and downspouts; exterior walls, doors and windows; ventilation openings and accessory structures.
SECTION 501—GENERAL
501.1 Scope. Buildings and structures in a wildland-urban interface area shall be constructed in accordance with the California Build- ing Code and this code.
Exceptions:
- Group U accessory structures not exceeding 120 square feet (11 m [2] ) in floor area where located not less than 50 feet (15 240 mm) from applicable buildings.
- Group U agricultural buildings not less than 50 feet (15 240 mm) from applicable buildings.
501.2 Objective. The objective of this chapter is to establish minimum standards to locate, design and construct buildings and structures or portions thereof for the protection of life and property, to resist damage from wildfires, and to mitigate building and structure fires from spreading to wildland fuels.
501.3 Fire-resistance-rated construction. Where this code requires 1-hour fire-resistance-rated construction, the fire-resistance rating of building elements, components or assemblies shall be determined in accordance with the test procedures set forth in ASTM E119 or UL 263.
Exceptions:
- The fire-resistance rating of building elements, components or assemblies based on the prescriptive designs prescribed in Section 721 of the California Building Code .
- The fire-resistance rating of building elements, components or assemblies based on the calculation procedures in accordance with Section 722 of the California Building Code .
501.4 Noncombustibility tests. The tests indicated in Section 501.4.1 shall serve as criteria for acceptance of noncombustible building materials. The term “noncombustible” does not apply to the flame spread characteristics of interior finish or trim materials. A material shall not be classified as a noncombustible building construction material if it is subject to an increase in combustibility or flame spread beyond the limitations herein established through the effects of age, moisture or other atmospheric conditions.
501.4.1 Noncombustible materials. Materials required to be noncombustible shall be tested in accordance with ASTM E136 and pass the test. Alternately, materials required to be noncombustible shall be tested in accordance with ASTM E2652 using the accep- tance criteria prescribed by ASTM E136.
CRC § 4811.15 Medium relevance — show source text
4811.15 Buildings without fire protection systems. Special hazards shall be reviewed by the fire code official (see special hazards Section 901.4.4).
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49 REQUIREMENTS FOR WILDLAND-URBAN INTERFACE FIRE AREAS
User notes :
Requirements for wildland-urban interface areas are now located in Part 7, California Wildland-Urban Interface Code. See Section 102.13 Wildland-Urban Interface.
The provisions of Part 7, California Wildland-Urban Interface Code shall apply to buildings and structures located in the wildland-urban interface (WUI) or Fire Hazard Severity Zone.
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CALIFORNIA FIRE CODE – MATRIX ADOPTION TABLE
CHAPTER 50 – HAZARDOUS MATERIALS—GENERAL PROVISIONS
(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
Adopting Agency BSC BSC-
CGSFM Col5 HCD Col7 Col8 DSA Col10 OSHPD Col12 Col13 Col14 Col15 Col16 BSCC DPH AGR DWR CEC CA SL SLC Adopting Agency BSC BSC-
CGT-24 T-19* 1 2 1/AC AC SS 1 1R 2 3 4 5 5 5 5 5 5 5 5 5 Adopt Entire Chapter Adopt Entire Chapter as
amended (amended sections
listed below)X Adopt only those sections that
are listed below[California Code of Regulations,
Title 19, Division 1]Chapter / Section 5001.5.1 X 5001.5.2 X 5003.1.1 X Table 5003.1.1(1) X Table 5003.1.1(2) X 5003.10.2 X 5003.10.2.1 X _5003.10. CRC § 1-2 Medium relevance — show source text
CHAPTER TOPICS Col2 CHAPTER SUBJECT 1-2 Administration and Definitions 3-4 Wildland-Urban Interface Area Designation and Requirements 5 Building Construction Regulations 6 Fire Protection Requirements 7 Referenced Standards Appendices A-I Adoptable and Informational Appendices Chapter 1 Scope and Administration.
Chapter 1 establishes the limits of applicability of the code and describes how the code is to be applied and enforced. The provisions of Chapter 1 establish the authority and duties of the code official appointed by the authority having jurisdiction and also establish the rights and privileges of the design professional, contractor and property owner.
Chapter 2 Definitions.
Chapter 2 is the repository of the definitions of terms used in the body of the code. The user of the code should be familiar with and consult this chapter because the definitions are essential to the correct interpretation of the code and because the user may not be aware that a term is defined.
Chapter 3 Wildland-Urban Interface Areas.
Chapter 3 provides for the fundamental aspect of applying the code—the legal declaration and establishment of wildland-urban interface areas within the adopting jurisdiction, mapping of the area, periodic review and updates.
Chapter 4 Wildland-Urban Interface Area Requirements.
The requirements of Chapter 4 apply to all occupancies in the wildland-urban interface and pertain to all of the following:
Fire service access to the property that is to be protected, including fire apparatus access roads and off-road driveways.
Premises identification.
Key boxes to provide ready access to properties secured by gated roadways or other impediments to rapid fire service access.
Fire protection water supplies, including adequate water sources, pumper apparatus drafting sites, fire hydrant systems and system reliability.
Fire department access to equipment such as fire suppression equipment and fire hydrants.
Chapter 5 Special Building Construction Regulations.
The regulations in Chapter 5 establish minimum standards for the location, design and construction of buildings and structures based on construction within a Fire Hazard Severity Zone or a Wildland-Urban Interface (WUI) Area.
The construction provisions of Chapter 5 are intended to supplement the requirements of the California Building Code and Califor- nia Residential Code and address mitigation of the unique hazards posed to buildings by wildfire and to reduce the hazards of building fires spreading to wildland fuels. This is accomplished by requiring ignition-resistant construction materials.
Chapter 6 Fire Protection Requirements.
Chapter 6 contains additional requirements for development and construction in Local Responsibility Areas (LRA) designated as Very High Fire Hazard Severity Zones and areas designated by the State Fire Marshal as State Responsibility Areas (SRA). While many of these provisions are found in Title 14 and Title 19 of the California Code of Regulations, they are replicated here for the code user. The local jurisdiction has the authority to apply the same regulations to LRA when the regulations are adopted by local ordinance.
The requirements in this chapter reference the process for adoption of Very High Fire Hazard Severity Zones in the LRA; criteria for evaluating existing subdivisions that are at significant fire risk and are without an adequate secondary egress; and criteria for fire safety provisions required in the Safety Element of a city or county General Plan.
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Frequently asked questions
Must I use WUI‑rated vents everywhere on my house if the property is inside a WUI area?
If the building is in a designated WUI or Fire Hazard Severity Zone and you provide ventilation openings (attic, soffit, foundation, crawl space, etc.), those openings must meet the WUI Code (Part 7) ember/flame resistance requirements. See § R806.1.1 and Part 7.
Can I just reduce vent area to avoid using WUI vents?
No. If you provide vents, you must meet the venting area rules (CRC § R806.2) and, where in WUI, the protective requirements of Part 7 per § R806.1.1. If you convert to an approved unvented attic assembly, see § R806.5 for the allowed unvented construction path.
Where do I find approved WUI vent products?
Part 7 and its referenced standards list product requirements; Appendix guidance and the WUI Code recommend OSFM‑labeled or listed WUI products. Check the OSFM product listing and the manufacturer’s WUI approval documentation as referenced by Part 7.
My local jurisdiction didn’t adopt the WUI Code — do I still need WUI vents?
Local adoption and enforcement matter. § R806.1.1 directs compliance “in accordance with Part 7.” Confirm with your local code official whether Part 7 has been adopted or whether local rules apply; Part 7 § 101.3.1 explains where it applies.
Are temporary fixes (mesh over vents) acceptable?
Appendix guidance suggests temporary mesh (e.g., noncombustible, corrosion‑resistant mesh sized in a narrow range) can be used as a temporary measure, but the permanent solution should be an approved WUI vent or installation that meets Part 7 requirements. Confirm with the code official.
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