CWUIC · California Wildland-Urban Interface Code
What home‑hardening features are recommended for survivability?
Appendix G of the CWUIC provides voluntary, practical home‑hardening recommendations (see **§ G101**, **§ G101.2**, **§ G101.2.1**) — prioritize a **Class A roof**, close ember entry points (seal gaps > **1/8 in**; install ember‑resistant vents and properly sized chimney/skylight mesh), use noncombustible gutters and flashing, replace nearby combustible fences or mulch, and maintain defensible clearances (e.g., keep combustibles away within **5 ft** and remove dead fuels within **30 ft**) to substantially increase survivability from wildfires.
Last reviewed: July 6, 2026
What the code requires — 2–4 sentences
Appendix G of the California Wildland‑Urban Interface Code provides voluntary home‑hardening recommendations to increase a building’s ignition resistance; it is informational and not mandatory (§ G101) . The appendix directs homeowners to a set of structural survivability practices in § G101.2 and lists specific home‑hardening features in § G101.2.1 that should be considered when replacing or maintaining components of a house to reduce wildfire ignition risk . These recommendations focus on blocking ember entry, using noncombustible/ignition‑resistant materials at key locations, and maintaining defensible clearances around the structure (see related defensible‑space guidance in § G101.3.1) .
The single most important practical rule: install Class A roofing and block ember entry points (vents, eaves, gaps > 1/8 inch (3.2 mm)) — these two steps are repeatedly emphasized in § G101.2.1 as major survivability upgrades.
Requirements in detail
Scope & status
- Appendix G is explicitly an informational, voluntary set of recommendations intended to help homeowners increase survivability of homes in the WUI; it is not a mandatory regulation by itself (§ G101) .
- § G101.2 frames the goal as increasing the ignition resistance of building components and notes many items are suitable upgrades at the time of normal replacement or maintenance .
- § G101.2.1 lists discrete retrofit or replacement features homeowners should consider to harden their homes against wildfire exposure .
Key home‑hardening features (summary)
The following are the primary features listed in § G101.2.1; each line is grounded in that section of the code. For full text see § G101.2.1.
- Replace roof coverings with a Class A roof assembly (ASTM E108 or UL 790). § G101.2.1 (1)
- Block eave spaces with noncombustible materials (bird stops). § G101.2.1 (2)
- Use noncombustible gutters/downspouts and gutter covers to keep debris out. § G101.2.1 (3)
- Chimney/stovepipe spark arrestors: noncombustible corrosion‑resistant metal mesh with openings 3/8 in (9.5 mm) to 1/2 in (12.7 mm). § G101.2.1 (4)
- Ember‑ and flame‑resistant vents; OSFM‑labeled WUI products preferred. Temporary mesh: 1/16 in (1.6 mm) to 1/8 in (3.2 mm) openings. § G101.2.1 (5)
- Seal/caulk gaps greater than 1/8 in (3.2 mm) around exposed rafters, blocking, siding, doors, etc., to prevent ember intrusion. § G101.2.1 (6, 7, 8)
- Replace windows with multipaned glazing with at least one pane tempered; OSFM WUI products recommended. § G101.2.1 (9)
- Use noncombustible, ignition‑resistant, or OSFM‑approved WUI products for siding and decks when replacing them. § G101.2.1 (10)
- Cover operable skylight openings with metal mesh not to exceed 1/8 in (3.2 mm) openings. § G101.2.1 (11)
- Install minimum 6‑inch metal flashing at the deck‑to‑wall intersection. § G101.2.1 (12)
- Enclose openings beneath decks or cantilevered construction with materials required in Section 504.5; for decks ≤ 4 ft (1219 mm) above grade, noncombustible/corrosion‑resistant mesh with 1/16–1/8 in openings is allowed. § G101.2.1 (13)
- Remove or replace combustible fences within 5 ft (1524 mm) of the structure; detached fences within 5 ft should be noncombustible or ignition‑resistant. § G101.2.1 (14)
Decision table — decision‑relevant thresholds and code references
| Feature / decision | Key value / threshold | Why it matters | Code Reference |
|---|---|---|---|
| Roof covering | Class A (ASTM E108 / UL 790) | Highest fire‑test classification for roof assemblies; reduces ignition from embers/radiant heat | § G101.2.1 |
| Eave & rafter gaps | Seal gaps > 1/8 in (3.2 mm) | Ember intrusion into attic/voids is a principal cause of structure ignition | § G101.2.1 |
| Chimney mesh | 3/8 in (9.5 mm) – 1/2 in (12.7 mm) | Prevents sparks/sparks escaping while allowing draft | § G101.2.1 |
| Vent mesh (temporary) | 1/16 in (1.6 mm) – 1/8 in (3.2 mm) | Stops most embers from entering vent openings | § G101.2.1 |
| Skylight openings | Mesh ≤ 1/8 in (3.2 mm) | Prevent ember entry through skylights | § G101.2.1 |
| Deck‑to‑wall flashing | 6 in minimum vertical metal flashing | Protects combustible siding at a common ignition intersection | § G101.2.1 |
| Under‑deck enclosure | If ≤ 4 ft (1219 mm) above grade, mesh 1/16–1/8 in allowable | Reduces ember accumulation under decks | § G101.2.1 |
| Combustible fence distance | Remove/replace fences within 5 ft (1524 mm) of structure | Close‑in combustible fences transmit fire/embers to walls | § G101.2.1 |
| Defensible space (maintenance) | Remove dead fuels, clear to 30 ft (9144 mm) around structures; keep combustibles away 5 ft (1524 mm) from decks/windows | Vegetation and stored combustibles provide fuel for ignition | § G101.3.1 |
Notes: the table entries above summarize the measurable thresholds in § G101.2.1 and § G101.3.1; the source text should be consulted directly for full context.
Exceptions & special cases
- Appendix G is informational: the items in § G101.2.1 are recommendations, not mandatory code requirements — do not treat Appendix G as enforced minimums (§ G101) .
- Some suggestions are framed as upgrades to make “when it is time to replace” that component — the code anticipates homeowners will use normal replacement cycles to upgrade to more resistant materials (§ G101.2) .
- Section 504.5 is referenced for acceptable materials to enclose under‑deck openings; the text of Section 504.5 was not included in the retrieved Appendix G excerpts, so consult the code or local authority for the materials list required by Section 504.5 (not reproduced here) .
Common mistakes
- Treating Appendix G as mandatory code rather than voluntary guidance — Appendix G is informational (§ G101) .
- Using plastic or combustible gutter covers or leaving gutters full of debris — § G101.2.1 calls for noncombustible gutters and covers and for gutter cleaning to prevent ember‑fed fires § G101.2.1 (3) and § G101.3.1 .
- Incorrect mesh sizing: installing mesh with openings larger than the code‑recommended sizes (e.g., vents or skylights) reduces effectiveness; temporary solutions must follow the stated opening ranges § G101.2.1 (4, 5, 11) .
- Ignoring small gaps: failing to caulk or plug gaps > 1/8 in (3.2 mm) around siding, doors, or rafters is a frequent oversight — these are explicit ember pathways in § G101.2.1 .
- Replacing one feature but neglecting companion measures — e.g., installing a Class A roof but leaving vents, eaves, and gutters vulnerable; § G101.2.1 is intended to be a package of measures.
Worked example — concrete scenario
Scenario: A homeowner’s existing house has an older roof (wood shake), soffit vents with large openings, single‑pane windows, and a combustible deck with gaps under it. The homeowner wants a prioritized list of actions that align with § G101.2.1.
Step 1 — Roof (high priority): When replacing the wood shake roof, install a Class A roof assembly tested to ASTM E108 or UL 790 (per § G101.2.1 (1)). This addresses the most common ignition route from ember showers.
Step 2 — Vents & eaves:
- Block eave/soffit spaces with noncombustible bird stops to close the space between roof covering and sheathing (§ G101.2.1 (2)) and caulk/plug any gaps > 1/8 in (3.2 mm) around exposed rafters and blocking (§ G101.2.1 (6)).
- Replace or retrofit vents with ember‑resistant vents (OSFM WUI products preferred) or temporarily cover vent openings with noncombustible mesh sized 1/16–1/8 in to block embers (§ G101.2.1 (5)).
Step 3 — Deck and flashing:
- Install 6‑inch metal flashing vertically at the deck‑to‑wall intersection (§ G101.2.1 (12)). If the deck is ≤ 4 ft above grade, enclose under‑deck openings with noncombustible mesh sized 1/16–1/8 in; otherwise use materials required by Section 504.5 (§ G101.2.1 (13)) — consult Section 504.5 for permitted materials (not reproduced here) .
Step 4 — Windows & miscellaneous: Replace single‑pane windows with multipaned units containing at least one tempered pane and remove combustibles within 5 ft (1524 mm) of windows and doors (§ G101.2.1 (9) and § G101.3.1) .
Step 5 — Chimney & gutters: Fit chimney with a corrosion‑resistant spark arrestor mesh 3/8–1/2 in, install noncombustible gutters and covers, and keep gutters free of leaves (per § G101.2.1 (3–4) and maintenance guidance in § G101.3.1) .
Result: This sequence implements the most impactful upgrades called out in § G101.2.1, closing major ember pathways and replacing the most vulnerable combustible components.
Related provisions
- § G101 — Appendix G general scope and intent (voluntary informational recommendations) .
- § G101.2 — Structural survivability and intent to increase ignition resistance (framework for the list in § G101.2.1) .
- § G101.2.1 — Detailed home‑hardening features (the primary list used above) .
- § G101.3.1 — Maintenance and defensible‑space practices (clearing distances, gutter/deck maintenance, storage of combustibles) that complement hardening measures .
- Section 504.5 — Referenced by § G101.2.1 for acceptable under‑deck enclosure materials (text not reproduced in the retrieved Appendix G excerpts) .
Code references
Grounded in the retrieved California Wildland-Urban Interface Code — click a citation to read the verbatim passage:
CWUIC § 2.1 High relevance — show source text
This appendix is for informational purposes and is not intended for adoption.
User notes:
About this appendix: Appendix G is an information appendix that provides discussion of some elements of the proposed self-defense mechanisms and their role in enhancing the protection of exposed structures in the wildland-urban interface. The items provided in this appendix provide owners with suggestions for increasing the survivability of their structure. These items are not mandatory but can be considered by owners to increase the safety of structures.
SECTION G101—GENERAL
G101.1 Identification of the problem. The California Wildland-Urban Interface Code establishes a set of minimum standards to reduce the loss of property from wildfire. The purpose of these standards is to prevent wildfire spreading from vegetation to a building. Many homes were built in the wildland-urban interface areas prior to the implementation of provisions found in this code. As a result, many homes are lacking in their ability to survive an approaching wildfire. Many of the features discussed in this appendix are designed as low- cost features to retrofit existing homes. Additionally, recommendations are provided beyond the minimum code requirements for those homeowners who desire to increase the survivability of their home. This appendix chapter provides a discussion of some possible self- defense features to enhance survivability and harden the structure against an approaching wildfire.
G101.2 Structural survivability. The home-hardening features listed in Section G101.2.1 were developed as a best practices guide to assist homeowners in increasing the ignition resistance of their homes from wildfires. Some of these items are based on upgrading to more stringent building materials when that building component is due for replacement as part of its normal maintenance or lifespan, such as the roof covering.
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.
CWUIC § 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.
CWUIC § 3.2 High relevance — show source text
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. Openings beneath decks which are four feet (1219 mm) or less above grade can be covered with a noncombustible and corrosion- resistant mesh with [1] / 16 -inch (1.6 mm) to [1] / 8 -inch (3.2 mm) openings. 14. Remove or replace combustible fences within 5 feet (1524 mm) of the structure. Detached fences that are located within 5 feet (1524 mm) of the structure should be replaced with noncombustible or ignition-resistant building materials.
G101.3 Defensible space features. The maintenance and defensible space features listed in Section G101.3.1 were developed as a best practices guide to assist homeowners to increase the effectiveness of their defensible space and improve the effects of the home-harden- ing features to increase the survivability of their homes from wildfires.
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APPENDIX G—VOLUNTARY HOME-HARDENING RECOMMENDATIONS
G101.3.1 Maintenance and defensible space. The following maintenance and operational procedures assist to limit the impact on a home from an approaching wildfire. 1. Roofs—regularly clean your roof, including roof-to-wall intersections and skylights to remove accumulated fallen leaves, needles and other flammable materials; repair damaged or deteriorated sections of the roof or roof covering; remove all trees, branches, shrubs or other plants adjacent to or overhanging buildings. 2. Rain gutters—keep roof gutters free of combustible debris. 3. Decks—regularly clean your deck, including deck-to-wall intersections to avoid the accumulation of fallen leaves, needles and other flammable materials; ensure that all combustible materials are removed from underneath, on top of or within five feet (1524 mm) of a deck or balcony. _4.
CWUIC § 1.11. High relevance — show source text
- The California Code of Regulations (CCR), Title 19, Division 1 provisions that are found in the California Wildland-Urban Interface Code are a reprint from the current CCR, Title 19, Division 1 text for the code user’s convenience only. The scope, applicability and appeals procedures of CCR, Title 19, Division I remain the same. The state agency does not adopt sections identified by the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.
The California Code of Regulations (CCR), Title 14, Division 1.5 provisions that are found in the California Wildland-Urban Interface Code are not listed in the Matrix Adoption Tables as they are not within the State Fire Marshal’s authority to adopt. These provisions are a reprint from the current CCR, Title 14, Division 1.5 text for the code user’s convenience only and are identified in the body of the code by square brackets containing references to applicable Title 14 sections.
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APPENDIX G-2 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE
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G VOLUNTARY HOME-HARDENING RECOMMENDATIONS
This appendix is for informational purposes and is not intended for adoption.
User notes:
About this appendix: Appendix G is an information appendix that provides discussion of some elements of the proposed self-defense mechanisms and their role in enhancing the protection of exposed structures in the wildland-urban interface. The items provided in this appendix provide owners with suggestions for increasing the survivability of their structure. These items are not mandatory but can be considered by owners to increase the safety of structures.
SECTION G101—GENERAL
G101.1 Identification of the problem. The California Wildland-Urban Interface Code establishes a set of minimum standards to reduce the loss of property from wildfire. The purpose of these standards is to prevent wildfire spreading from vegetation to a building. Many homes were built in the wildland-urban interface areas prior to the implementation of provisions found in this code. As a result, many homes are lacking in their ability to survive an approaching wildfire. Many of the features discussed in this appendix are designed as low- cost features to retrofit existing homes. Additionally, recommendations are provided beyond the minimum code requirements for those homeowners who desire to increase the survivability of their home. This appendix chapter provides a discussion of some possible self- defense features to enhance survivability and harden the structure against an approaching wildfire.
G101.2 Structural survivability. The home-hardening features listed in Section G101.2.1 were developed as a best practices guide to assist homeowners in increasing the ignition resistance of their homes from wildfires. Some of these items are based on upgrading to more stringent building materials when that building component is due for replacement as part of its normal maintenance or lifespan, such as the roof covering.
CWUIC § 3.1 High relevance — show source text
Detached fences that are located within 5_ feet (1524 mm) of the structure should be replaced with noncombustible or ignition-resistant building materials.
G101.3 Defensible space features. The maintenance and defensible space features listed in Section G101.3.1 were developed as a best practices guide to assist homeowners to increase the effectiveness of their defensible space and improve the effects of the home-harden- ing features to increase the survivability of their homes from wildfires.
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APPENDIX G—VOLUNTARY HOME-HARDENING RECOMMENDATIONS
G101.3.1 Maintenance and defensible space. The following maintenance and operational procedures assist to limit the impact on a home from an approaching wildfire. 1. Roofs—regularly clean your roof, including roof-to-wall intersections and skylights to remove accumulated fallen leaves, needles and other flammable materials; repair damaged or deteriorated sections of the roof or roof covering; remove all trees, branches, shrubs or other plants adjacent to or overhanging buildings. 2. Rain gutters—keep roof gutters free of combustible debris. 3. Decks—regularly clean your deck, including deck-to-wall intersections to avoid the accumulation of fallen leaves, needles and other flammable materials; ensure that all combustible materials are removed from underneath, on top of or within five feet (1524 mm) of a deck or balcony. 4. Chimneys—ensure spark arrestor is in place; remove all branches within 10 feet of any chimney or stovepipe outlet. 5. Windows—remove or relocate all combustibles away from windows. Older windows that are single-pane or double-pane without tempering can be vulnerable to direct flame contact or radiant heat exposure; remove vegetation or other combus- tible materials that are within five feet of windows.
6. Doors—inspect the door for dry rot, gaps, cracks and warping and caulk or plug gaps greater than [1] / 8 inch. Install weather stripping to fill gaps greater than [1] / 8 inch (3.2 mm) between garage doors and door frames to prevent ember intrusion; remove vegetation or other combustible materials that are within five feet (1524 mm) of doors. 7. Exterior walls—inspect exterior siding for dry rot, gaps, cracks and warping and caulk or plug gaps greater than [1] / 8 inch in siding and replace any damaged boards, including those with dry rot. 8. Firewood—exposed firewood is stored at least 30 feet (9144 mm) away from structures or completely covered in a fire-resis- _tant material that will not allow embers to penetrate.
CWUIC § 1-3 High relevance — show source text
Appendix G Voluntary Home-Hardening Recommendations.
Appendix G is an informational appendix that provides discussion of some elements of the proposed self-defense mechanisms and their role in enhancing the protection of exposed structures in the wildland-urban interface. The items provided in this appendix provide owners with suggestions for increasing the survivability of their structure. These items are not mandatory but can be considered by owners to increase the safety of structures.
Appendix H Referenced California Documents.
Appendix H contains portions of California statutes and regulations located in other documents. They are reprinted in Appendix H to aid the user in understanding the requirements applicable to wildland-urban interface areas and to provide a background for the provi- sions. Much of the text in the CWUIC is based on the requirements found in these other documents.
Appendix I Board of Appeals.
Appendix I contains the provisions for appeal and the establishment of a board of appeals. The provisions include the application for an appeal, the makeup of the board of appeals and the conduct of the appeal process.
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CONTENTS
CHAPTER 1 ADMINISTRATION. . . . . . . . . . . . . . . . . . . . . . .1-3
DIVISION I CALIFORNIA ADMINISTRATION
1.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
1.11 Office of the State Fire Marshal . . . . . . . . . . . . . . . . . . . 1-4
1.12 Board of Forestry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
DIVISION II SCOPE AND ADMINISTRATION . . . . . . . . . . . . . 1-15
PART 1—GENERAL PROVISIONS. . . . . . . . . . . . . . . . . . . . . . . . . . 1-15
101 Scope and General Requirements. . . . . . . . . . . . . . 1-15
102 Applicability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16
PART 2—ADMINISTRATION AND ENFORCEMENT . . . . . . . . . . . 1-17
103 Code Compliance Agency . . . . . . . . . . . . . . . . . . . . . 1-17
104 Duties and Powers of the Code Official . . . . . . . . . 1-17
105 Permits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19
106 Construction Documents . . . . . . . . . . . . . . . . . . . . . 1-20
107 Temporary Uses, Equipment and Systems . . . . . . 1-21
CWUIC § 1-3 High relevance — show source text
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.
Appendix G Voluntary Home-Hardening Recommendations.
Appendix G is an informational appendix that provides discussion of some elements of the proposed self-defense mechanisms and their role in enhancing the protection of exposed structures in the wildland-urban interface. The items provided in this appendix provide owners with suggestions for increasing the survivability of their structure. These items are not mandatory but can be considered by owners to increase the safety of structures.
Appendix H Referenced California Documents.
Appendix H contains portions of California statutes and regulations located in other documents. They are reprinted in Appendix H to aid the user in understanding the requirements applicable to wildland-urban interface areas and to provide a background for the provi- sions. Much of the text in the CWUIC is based on the requirements found in these other documents.
Appendix I Board of Appeals.
Appendix I contains the provisions for appeal and the establishment of a board of appeals. The provisions include the application for an appeal, the makeup of the board of appeals and the conduct of the appeal process.
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CONTENTS
CHAPTER 1 ADMINISTRATION. . . . . . . . . . . . . . . . . . . . . . .1-3
DIVISION I CALIFORNIA ADMINISTRATION
1.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
CWUIC § 1.11. High relevance — show source text
Additionally, make sure you have 10 feet (3048 mm) of clearance_ around your wood piles. 9. Fences—remove or relocate all vegetation, combustibles and combustible debris adjacent to and underneath fences. 10. Replace wood mulch products within five feet (1524 mm) of all structures with noncombustible products such as dirt, stone, or gravel. 11. Remove all dead or dying grass, plants, shrubs, trees, branches, leaves, weeds, and pine needles within 30 feet (9144 mm) of all structures or to the property line. 12. Be sure to store combustible outdoor furnishings away from your home when not in use. 13. Remember to properly store retractable awnings and umbrellas when not in use so they do not collect leaves and embers.
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CALIFORNIA WILDLAND-URBAN INTERFACE CODE – MATRIX ADOPTION TABLE
APPENDIX H – REFERENCED CALIFORNIA DOCUMENTS
(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
(Not adopted by the State Fire Marshal)
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)Adopt only those sections that
are listed below[California Code of Regulations,
Title 19, Division 1]Chapter / Section - The California Code of Regulations (CCR), Title 19, Division 1 provisions that are found in the California Wildland-Urban Interface Code are a reprint from the current CCR, Title 19, Division 1 text for the code user’s convenience only. The scope, applicability and appeals procedures of CCR, Title 19, Division I remain the same. The state agency does not adopt sections identified by the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.
CWUIC § 4291.5 High relevance — show source text
F**|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation| |F101|General|Y||||||||| |F101.1|Characteristics of_fire-_
smart vegetation|Y||||||||| |Appendix G|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations| |G101|General|Y|||||||4291.5|| |G101.1|Identification of the
problem|Y||||||||| |G101.2|Structural
survivability|Y||||||||| |G101.2.1|Home-hardening
features|Y||||||||| |G101.3|Defensible space
features|Y||||||||| |G101.3.1|Maintenance and
defensible space|Y||||||||| |Appendix H|Referenced California Documents|Referenced California Documents|Referenced California Documents|Referenced California Documents|Referenced California Documents|Referenced California Documents|Referenced California Documents|Referenced California Documents|Referenced California Documents|Referenced California Documents| ||General|N||||||||| |H101|California Civil Code|N||||||||| |H102|California Govern-
ment Code|N||||||Various||| |H103|California Public
Resources Code|N|||||||Various|| |H104|California Code of
Regulations, Title 14,
Division 1.5|N||||Various||||| |H104.1|Subchapter 2 State
Minimum Fire Safe
Regulations|N||||Subchapter 2||||| |H104.2|Subchapter 3 Fire
Hazard|N||||Subchapter 3||||| |H105|California Code of
Regulations, Title 19|N|||||2201|||| |H106|Health and Safety
Code|N||||||||Various| |H107|Cross Reference Tool|N|||||||||2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE APPENDIX H-35
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS
CWUIC § 4291.5 Medium relevance — show source text
Response_|N||||||||| |Appendix D|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption| |D101|Model ordinance|N|||4911|||||| |Appendix E|RESERVED|RESERVED|RESERVED|RESERVED|RESERVED|RESERVED|RESERVED|RESERVED|RESERVED|RESERVED| |Appendix F|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation| |F101|General|Y||||||||| |F101.1|Characteristics of_fire-_
smart vegetation|Y||||||||| |Appendix G|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations|Voluntary Home-Hardening Recommendations| |G101|General|Y|||||||4291.5|| |G101.1|Identification of the
problem|Y||||||||| |G101.2|Structural
survivability|Y||||||||| |G101.2.1|Home-hardening
features|Y||||||||| |G101.3|Defensible space
features|Y||||||||| |_G101.3.CWUIC § 1102.6 Medium relevance — show source text
The text is reprinted below to aid the user in understanding the requirements applicable to wildland-urban interface areas and to provide a background for the provisions.
SECTION H101—CALIFORNIA CIVIL CODE
Sections 1102.6f and 1102.19.
1102.6f.
(a) On or after January 1, 2021, in addition to any other disclosure required pursuant to this article, the seller of any real property subject to this article that is located in a high or very high fire hazard severity zone, as identified by the Director of Forestry and Fire Protection pursuant to Section 51178 of the Government Code or Article 9 (commencing with Section 4201) of Chapter 1 of Part 2 of Division 4 of the Public Resources Code, shall provide a disclosure notice to the buyer, if the home was constructed before January 1, 2010, that includes the following information: (1) A statement as follows: “This home is located in a high or very high fire hazard severity zone and this home was built before the implementation of the Wildfire Urban Interface building codes which help to fire harden a home. To better protect your home from wildfire, you might need to consider improvements. Information on fire hardening, including current building standards and information on minimum annual vegetation management standards to protect homes from wildfires, can be obtained on the internet website http://www.readyforwildfire.org.” (2) On or after July 1, 2025, a list of low-cost retrofits developed and listed pursuant to Section 51189 of the Government Code. The notice shall disclose which listed retrofits, if any, have been completed during the time that the seller has owned the property. (3) A list of the following features that may make the home vulnerable to wildfire and flying embers. The notice shall disclose which of the listed features, if any, that exist on the home of which the seller is aware: (A) Eave, soffit, and roof ventilation where the vents have openings in excess of one-eighth of an inch or are not flame and ember resistant.
(B) Roof coverings made of untreated wood shingles or shakes. (C) Combustible landscaping or other materials within five feet of the home and under the footprint of any attached deck. (D) Single pane or nontempered glass windows. (E) Loose or missing bird stopping or roof flashing. (F) Rain gutters without metal or noncombustible gutter covers. (4) If, pursuant to Section 51182 of the Government Code, a seller has obtained a final inspection report described in that section, the seller shall provide to the buyer a copy of that report or information on where a copy of the report may be obtained. (5) This section shall not be construed as a requirement, instruction, or consideration for present or future building code formula- tion, including, but not limited to, the Wildland-Urban Interface building standards (Chapter 7A (commencing with Section 701A.1) of Part 2 of Title 24 of the California Code of Regulations).
1102.19.
(a) On and after July 1, 2021, a seller of a real property subject to this article that is located in a high or very high fire hazard sever- _ity zone,
CWUIC § 3.1 Medium relevance — show source text
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 wildland-urban interface areas; protection of pumps and water supplies; and limits on temporary uses within the wildland-urban interface area.
SECTION A101—GENERAL
A101.1 Scope. The provisions of this appendix establish general requirements applicable to new and existing properties located within wildland-urban interface areas .
A101.2 Objective. The objective of this appendix is to provide necessary fire protection measures to reduce the threat of wildfire in a wildland-urban interface area and improve the capability of controlling such fires.
SECTION A102—VEGETATION CONTROL
A102.1 General. Vegetation control shall comply with Sections A102.2 through A102.4.
A102.2 Clearance of brush or vegetative growth from roadways. The code official is authorized to require areas within 10 feet (3048 mm) on each side of portions of fire apparatus access roads and driveways to be cleared of nonfire-smart vegetation growth.
Exception: Single specimens of trees, ornamental vegetative fuels or cultivated ground cover, such as green grass, ivy, succulents or similar plants used as ground cover, provided they do not form a means of readily transmitting fire.
A102.3 Clearance of brush and vegetative growth from electrical transmission and distribution lines. Clearance of brush and vegetative growth from electrical transmission and distribution lines shall be in accordance with Sections A102.3.1 through A102.3.2.3.
Exception: Sections A102.3.1 through A102.3.2.3 do not authorize persons not having legal right of entry to enter on or damage the property of others without consent of the owner.
A102.3.1 Support clearance. Persons owning, controlling, operating or maintaining electrical transmission or distribution lines shall have an approved program in place that identifies poles or towers with equipment and hardware types that have a history of becoming an ignition source, and provides a combustible free space consisting of a clearing of not less than 10 feet (3048 mm) in each direction from the outer circumference of such pole or tower during such periods of time as designated by the code official.
Exception: Lines used exclusively as telephone, telegraph, messenger call, alarm transmission or other lines classed as communication circuits by a public utility.
A102.3.2 Electrical distribution and transmission line clearances. Clearances between vegetation and electrical lines shall be in accordance with Sections A102.3.2.1 through A102.3.2.3.
A102.3.2.1 Trimming clearance. At the time of trimming, clearances not less than those established by Table A102.3.2.1 shall be provided. The radial clearances shown are minimum clearances that shall be established, at time of trimming, between the vegetation and the energized conductors and associated live parts.
Exception: The code official is authorized to establish minimum clearances different than those specified by Table A102.3.2.1 when evidence substantiating such other clearances is submitted to and approved by the code official.
Frequently asked questions
How mandatory are the items in Appendix G?
Appendix G is informational and voluntary; the home‑hardening items in § G101.2.1 are recommendations to increase ignition resistance, not mandatory code requirements (§ G101) .
What is the most effective single upgrade?
Replacing a combustible roof with a Class A roof assembly and closing ember entry points (vents, eaves, gaps > 1/8 in) are singled out as among the most impactful measures in § G101.2.1 .
What mesh sizes should I use for vents, chimneys, and skylights?
Temporary vent mesh: 1/16–1/8 in (1.6–3.2 mm); chimney spark arrestor: 3/8–1/2 in (9.5–12.7 mm); skylight screen openings not to exceed 1/8 in (3.2 mm) — see § G101.2.1 (4, 5, 11) .
If my deck is low to the ground, can I use mesh under it?
Yes — openings beneath decks 4 ft (1219 mm) or less above grade may be covered with noncombustible, corrosion‑resistant mesh with 1/16–1/8 in openings; otherwise follow materials in Section 504.5 referenced by § G101.2.1 (13) .
Do I still need defensible space if I harden my home?
Yes — structural hardening and defensible space are complementary. Appendix G’s maintenance guidance (e.g., clearing combustible materials within 5 ft of decks/windows and removing dead fuels within 30 ft) supports hardening measures (§ G101.3.1) .
More in California Wildland-Urban Interface Code
- Administration and Definitions
- Board of Appeals, Administration & Enforcement (permits, code official duties, appeals process)
- Wildland‑Urban Interface Area Designation & Mapping
- Fire Service Access & Water Supply (fire apparatus roads, driveways, hydrants, draft sites, standby power)
- Wildland‑Urban Interface Area Requirements (access, water, premises identification, key boxes)
- Referenced Standards & Test Methods
- Special Building Construction Regulations (ignition‑resistant construction, roof/vent/assembly requirements)
- Appendices and Model Ordinances (vegetation plans, severity‑zone adoption, home‑hardening guidance)
- Fire Protection Requirements (fire protection plans, systems, safety element provisions)
- Referenced California Documents & Matrix (CCR/Title 14 & 19 cross‑references, statutory references)
- Vegetation Management & Defensible Space (vegetation plans, maintenance, fire‑smart characteristics)
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