Special Building Construction Regulations (ignition‑resistant construction, roof/vent/assembly requirements)

Grounded in the retrieved California Wildland-Urban Interface Code — click a citation to read the verbatim passage:

• CWUIC § 504.3 High relevance — show source text

  504.3 Protection of enclosed eaves. The exposed underside of enclosed roof eaves and soffits shall be protected on the exposed underside by one or more of the following:

  1. Noncombustible materials.

  2. Ignition-resistant building materials. 3. Materials approved for not less than 1-hour fire-resistance-rated construction on the exterior side, as tested in accordance with ASTM E119 or UL 263.

  4. 2-inch (51 mm) nominal dimension lumber . 5. 1-inch (25 mm) nominal fire-retardant-treated lumber or [3] / 4 -inch (19.1 mm) nominal fire-retardant-treated plywood, identified for exterior use and complying with Section 2303.2 of the California Building Code . 6. Boxed-in roof eave soffit assemblies with an underside that meets the performance criteria in Section 504.7.2 when tested in accordance with the test procedures set forth in ASTM E2957. 7. Boxed-in roof eave soffit assemblies with an underside that meets the performance criteria in accordance with the test proce- dures set forth in SFM Standard 12-7A-3.

  Facias are required and shall be ignition-resistant building materials , fire-retardant-treated wood labeled for exterior use and complying with Section 2303.2 of the California Building Code, materials approved for not less than 1-hour fire-resistance-rated construction or 2-inch (51 mm) nominal dimension lumber.

  504.3.1 Protection of open eaves. The exposed roof deck on the underside of unenclosed roof eaves shall consist of one or more of the following:

  1. Noncombustible material.

  2. Ignition-resistant building material. 3. Fire-retardant-treated wood labeled for exterior use and complying with Section 2303.2 of the California Building Code. 4. Materials approved for not less than 1-hour fire-resistance-rated construction on the exterior side, as tested in accordance with ASTM E119 or UL 263.

  5. 2-inch (51 mm) nominal dimension lumber. 6. One layer of [5] / 8 -inch (16 mm) Type X gypsum sheathing applied behind an exterior covering on the underside of the roof deck.

  7. The exterior portion of a 1-hour fire-resistance-rated exterior assembly, as tested in accordance with ASTM E119 or UL 263, applied to the underside of the roof deck designed for exterior fire exposure, including assemblies using the gypsum panel and sheathing products listed in the Gypsum Association Fire Resistance Design Manual.

  2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 5-5

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  �

  �

  �

  �

  �

  SPECIAL BUILDING CONSTRUCTION REGULATIONS

  Facias, if provided, shall be of fire-retardant-treated wood labeled for exterior use and complying with Section 2303.2 of the Cali- fornia Building Code, ignition-resistant building materials, materials approved for not less than 1-hour fire-resistance-rated construction or 2-inch (51 mm) nominal dimension lumber.

• CWUIC § 8.1 High relevance — show source text

  8.1_ –504.8.2|||X||||||||||||||||||||| |504.9|||X||||||||||||||||||||| |504.9.1 –504.9.3|||X||||||||||||||||||||| |504.10.1 – 504.10.3|||X||||||||||||||||||||| |504.11 – 504.11.1|||X||||||||||||||||||||| |504.11.2 –504.11.6|||X||||||||||||||||||||| |505 – 506_Reserved_|||X||||||||||||||||||||| |507.1|||X|||||||||||||||||||||

  • 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.

  2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 5-1

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  5-2 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  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:

  1. 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.
  2. Group U agricultural buildings not less than 50 feet (15 240 mm) from applicable buildings.
• CWUIC § 1-2 High 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:

  1. Fire service access to the property that is to be protected, including fire apparatus access roads and off-road driveways.

  2. Premises identification.

  3. Key boxes to provide ready access to properties secured by gated roadways or other impediments to rapid fire service access.

  4. Fire protection water supplies, including adequate water sources, pumper apparatus drafting sites, fire hydrant systems and system reliability.

  5. 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.

  2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE xi

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

• CWUIC § 504.10.1 High relevance — show source text

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  SPECIAL BUILDING CONSTRUCTION REGULATIONS

  lation, foundations and crawl spaces, or any other opening intended to permit ventilation, either in a horizontal or vertical surface, shall be in accordance with Section 504.10.1 or Section 504.10.2 to resist building ignition from the intrusion of burning embers and flame through the ventilation openings.

  504.10.1 Performance requirements. Ventilation openings shall be fully covered with Wildfire Flame and Ember Resistant vents approved and listed by the California State Fire Marshal, or WUI vents, tested in accordance with ASTM E2886, to demonstrate compliance with all the following requirements:

  1. There shall be no flaming ignition of the cotton material during the Ember Intrusion Test.
  2. There shall be no flaming ignition during the Integrity Test portion of the Flame Intrusion Test.
  3. The maximum temperature of the unexposed side of the vent shall not exceed 662°F (350°C).

  504.10.2 Off ridge and ridge vents. Vents that are installed on a sloped roof, such as dormer vents, shall comply with all of the following: 1. Vents shall be covered with a mesh where the dimensions of the mesh therein shall be a minimum of [1] / 16 inch (1.6 mm) and shall not exceed [1] / 8 inch (3.2 mm) in diameter.

  2. The vent and mesh material shall be noncombustible.

  3. The vent and mesh material shall be corrosion resistant.

  504.10.3 Vent locations. Gable-end and dormer vents shall be located not less than 10 feet (3048 mm) from lot lines. Underfloor ventilation openings shall be located as close to grade as practical.

  504.11 Accessory buildings and miscellaneous structures. Accessory buildings and miscellaneous structures that have the potential to pose a significant exterior fire exposure hazard during wildfires shall be constructed to conform to the ignition-resistance require- ments of this section.

  504.11.1 Applicability . Sections 504.11.2 through 504.11.6 apply to buildings accessory to an applicable building on the same lot, and attached or detached miscellaneous structures that require a building permit, including but not limited to trellises, arbors, patio covers, gazebos and similar structures.

  Exceptions: 1. Decks shall comply with the requirements of Section 504.7.3. 2. Awnings and canopies shall comply with the requirements of Section 3105 of the California Building Code.

  504.11.2 Miscellaneous structures and accessory buildings within 3 feet. Miscellaneous structures that require a permit, and accessory buildings of any size, when separated from an applicable building on the same lot by a distance of less than 3 feet (914 mm), shall be constructed of noncombustible materials or ignition-resistant building materials as described in Section 503.2.4.

• CWUIC § 503.1 High relevance — show source text

  1||||||| |502|RESERVED|N||||||||| |503|Ignition-resistant
  construction and
  material|Y||704A||||||| |503.1|General|Y||701A.3||||||| |503.2|Ignition-resistant
  building material|Y||707A.3 #2||||||| |503.2.1|Noncombustible
  material|Y||704A.4 #1||||||| |503.2.2|Fire-retardant-
  treated wood|Y||704A.4 #2||||||| |503.2.3|Fire-retardant-
  treated wood roof
  coverings|Y||705A.1||||||| |503.2.4|Other ignition-
  resistant building
  material|Y||704A.3||||||| |503.2.4.1|Flame spread|Y||704A.3 #1||||||| |503.2.4.2|Flame front|Y||704A.3 #2||||||| |503.2.4.3|Weathering|Y||703A.5.1||||||| |503.2.4.3.1|Evaluation require-
  ments for weathering|Y||703A.5.2
  703A.5.2.1||||||| |503.2.4.3.2|Wood-plastic
  composite materials|Y||703A.6|||||||

  APPENDIX H-28 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS

  2025 CWUIC—continued	Col2	Adopted Yes/No	IWUIC Section	CBC Section	CFC Section	Title 14, Division 1.5 Section	Title 19, Division 1 Section	Gov Code Section	PRC Section	HSC Section
  Section	Title	Title	Title	Title	Title	Title	Title	Title	Title	Title
  Chapter 5	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations
  503.2.4.3.3	Plastic lumber materials	Y		703A.6
  503.2.5	Surface treatment protection	Y		703A.5.3
  503.3	Standards of quality	Y		703A.1
  503.3.1	Qualification by testing	Y		703A.2
  503.3.2	Approved agency	Y		703A.3
  503.3.3	Labeling	Y		703A.4
  _503.3.

• CWUIC § 1.5 High relevance — show source text

  2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE APPENDIX H-29

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS

  2025 CWUIC—continued	Col2	Adopted Yes/No	IWUIC Section	CBC Section	CFC Section	Title 14, Division 1.5 Section	Title 19, Division 1 Section	Gov Code Section	PRC Section	HSC Section
  Section	Title	Title	Title	Title	Title	Title	Title	Title	Title	Title
  Chapter 5	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations
  504.9.1	Garage doors	Y
  504.9.2	Garage door perimeter gap	Y		708A.4
  504.9.3	Conditions of accep- tance for ASTM E2707	Y		707A.4.1
  504.10	Vents	Y		706A.1
  504.10.1	Performance requirements	Y		706A.2
  504.10.2	Off ridge and ridge vents	Y		706A.2.1
  504.10.3	Vent locations	Y
  504.11	Accessory buildings and miscellaneous structures	Y		710A.1
  504.11.1	Applicability	Y		710A.2
  504.11.2	Miscellaneous struc- tures and accessory buildings within 3 feet	Y		710A.3.1
  504.11.3	Accessory buildings greater than 120 square feet, located 3 feet or more but less than 50 feet	Y		710A.3.2
  504.11.4	Accessory buildings 120 square feet or less, located 3 feet or more but less than 50 feet	Y		710A.3.3
  504.11.5	Miscellaneous struc- tures located 3 feet or more but less than 50 feet	Y		710A.3.4
  504.11.6	Roof construction			710A.4
  505	RESERVED	N
  506	RESERVED	N
  507	Replacement or repair of roof coverings	Y		705A.1 1505.1.1
  507.1	General	Y		705A.1 1505.1.

• CWUIC § 3.2 High relevance — show source text

  3.2|||||||| |404.4|Hydrants|Y|||507.5|||||| |404.5|Adequate water
  supply|Y|||507.3|1275.02(b)||||| |404.6|Reserved|N||||||||| |404.7|Obstructions|Y|||507.5.4|||||| |404.8|Identification|Y||||1275.04(a)||||| |404.9|Testing and
  maintenance|Y|||507.5.2|||||| |404.10|Reliability|Y|||507.5.2|||||| |404.10.1|Objective|Y|404.10.1|||||||| |404.10.2|Clearance of fuel|Y|||4907.1|||||| |404.10.3|Standby power|Y|||507.5.2|||||| |Chapter 5|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations| |501|General|Y||701A||||||| |501.1|Scope|Y||701A.3||||||| |501.2|Objective|Y||701A.2||||||| |501.3|Fire-resistance-rated
  construction|Y||703.2.1.5||||||| |501.4|Noncombustibility
  tests|Y||703.3||||||| |501.4.1|Noncombustible
  materials|Y||703.3.1||||||| |502|RESERVED|N||||||||| |503|Ignition-resistant
  construction and
  material|Y||704A||||||| |503.1|General|Y||701A.3||||||| |503.2|Ignition-resistant
  building material|Y||707A.3 #2||||||| |503.2.1|Noncombustible
  material|Y||704A.4 #1||||||| |503.2.2|Fire-retardant-
  treated wood|Y||704A.4 #2||||||| |503.2.3|Fire-retardant-
  treated wood roof
  coverings|Y||705A.1||||||| |503.2.4|Other ignition-
  resistant building
  material|Y||704A.3||||||| |503.2.4.1|Flame spread|Y||704A.3 #1||||||| |503.2.4.2|Flame front|Y||704A.3 #2||||||| |503.2.4.3|Weathering|Y||703A.5.1||||||| |503.2.4.3.1|Evaluation require-
  ments for weathering|Y||703A.5.2
  703A.5.2.1||||||| |503.2.4.3.2|Wood-plastic
  composite materials|Y||703A.6|||||||

  APPENDIX H-28 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS

• CWUIC § 6.3.1. High relevance — show source text

  6.3.1.|The fastening system shall resist the wind forces in Section 1609.6.3.1.|The fastening system shall resist the wind forces in Section 1609.6.3.1.| |130|0-60|The fastening system shall resist the wind forces in Section 1609.6.3.1.|The fastening system shall resist the wind forces in Section 1609.6.3.1.|The fastening system shall resist the wind forces in Section 1609.6.3.1.| |All|> 60|The fastening system shall resist the wind forces in Section 1609.6.3.1.|The fastening system shall resist the wind forces in Section 1609.6.3.1.|The fastening system shall resist the wind forces in Section 1609.6.3.1.| |For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s, 1 pound per square foot = 4.882 kg/m2.
  a. Minimum fastener size. Corrosion-resistant nails not less than No. 11 gage with5/16-inch head. Fasteners shall be long enough to penetrate into the sheathing3/4 inch or
  through the thickness of the sheathing, whichever is less. Attaching wire for clay and concrete tile shall not be smaller than 0.083 inch.
  b. Snow areas. Not fewer than two fasteners per tile are required or battens and one fastener.
  c. Roof slopes greater than 24:12. The nose of all tiles shall be securely fastened.
  d. Horizontal battens. Battens shall be not less than 1 inch by 2 inches nominal. Provisions shall be made for drainage by a riser of not less than1/8 inch at each nail or by 4-foot-
  long battens with not less than a1/2-inch separation between battens. Horizontal battens are required for slopes over 7:12.
  e. Perimeter fastening areas include three tile courses but not less than 36 inches from either side of hips or ridges and edges of eaves and_gable_ rakes.
  f._ Vasd_ shall be determined in accordance with Section 1609.3.1.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s, 1 pound per square foot = 4.882 kg/m2.
  a. Minimum fastener size. Corrosion-resistant nails not less than No. 11 gage with5/16-inch head. Fasteners shall be long enough to penetrate into the sheathing3/4 inch or
  through the thickness of the sheathing, whichever is less. Attaching wire for clay and concrete tile shall not be smaller than 0.083 inch.
  b. Snow areas. Not fewer than two fasteners per tile are required or battens and one fastener.
  c. Roof slopes greater than 24:12. The nose of all tiles shall be securely fastened.
  d. Horizontal battens. Battens shall be not less than 1 inch by 2 inches nominal. Provisions shall be made for drainage by a riser of not less than1/8 inch at each nail or by 4-foot-
  long battens with not less than a1/2-inch separation between battens.

• CWUIC § 0.90 High relevance — show source text

  00|0.90|DR|DR|DR| |Minimum
  1× wood
  furringd|Minimum
  2× wood
  stud|No.10
  wood
  screw|1|24|4.00|0.90|DR|DR|DR|2.85|DR|DR|DR|DR| |Minimum
  1× wood
  furringd|Minimum
  2× wood
  stud|1/4″
  lag screw|11/2|12|4.00|2.65|1.90|1.50|0.90|4.00|1.65|1.05|0.80|DR| |Minimum
  1× wood
  furringd|Minimum
  2× wood
  stud|1/4″
  lag screw|11/2|16|4.00|1.95|1.25|0.95|0.50|4.00|1.10|0.65|DR|DR| |Minimum
  1× wood
  furringd|Minimum
  2× wood
  stud|1/4″
  lag screw|11/2|24|4.00|1.10|0.65|DR|DR|3.25|0.50|DR|DR|DR| |For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa, 1 pound per square inch = 6.895 kPa.
  DR = Design Required.
  o.c. = On Center.
  a. Wood framing and furring shall be Spruce-pine-fir or any wood species with a specific gravity of 0.42 or greater in accordance with AWC NDS.
  b. Nail fasteners shall comply with ASTM F1667, except nail length shall be permitted to exceed ASTM F1667 standard lengths.
  c. The thickness of wood structural panels complying with the specific gravity requirements of Note a shall be permitted to be included in satisfying the minimum required pene-
  tration into framing.
  d. Where the required cladding fastener penetration into wood material exceeds3/4 inch and is not more than 11/2 inches, a minimum 2× wood furring or an approved design shall
  be used.
  e. Foam sheathing shall have a minimum compressive strength of 15 psi in accordance with ASTM C578 or ASTM C1289.
  f. Furring shall be spaced not more than 24 inches on center, in a vertical or horizontal orientation. In a vertical orientation, furring shall be located over wall studs and attached
  with the required fastener spacing. In a horizontal orientation, the indicated 8-inch and 12-inch fastener spacing in furring shall be achieved by use of two fasteners into studs
  at 16 inches and 24 inches on center, respectively.
  g. Cladding weight is the maximum weight of cladding materials in pounds per square foot of wall area. The 3 psf category typically applies to panel and lap siding materials; the
  11 psf category typically applies to conventional three-coat stucco of7/8-inch thickness; and 15 psf to 25 psf categories typically apply to adhered masonry veneers.|For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa, 1 pound per square inch = 6.895 kPa.
  DR = Design Required.
  o.c. = On Center.
  a.

• CWUIC § 0.125 High relevance — show source text

  Exception: Materials having a structural base of noncombustible material as determined in accordance with ASTM E136, or with ASTM E2652 using the acceptance criteria prescribed by ASTM E136, and a surfacing of not more than 0.125 inch (3.18 mm) in thick- ness having a flame spread index not greater than 50 when tested in accordance with ASTM E84 or UL 723 shall be acceptable as noncombustible.

  SECTION 502— RESERVED

  SECTION 503—IGNITION-RESISTANT CONSTRUCTION AND MATERIAL

  503.1 General. Buildings and structures hereafter constructed, modified or relocated into or within wildland-urban interface areas shall meet the construction requirements in accordance with Chapter 5 . Materials required to be ignition-resistant building materials shall comply with the requirements of Section 503.2.

  Exceptions:

  1. New accessory buildings and miscellaneous structures complying with Section 504.11. 2. Additions to and remodels of buildings originally constructed prior to July 1, 2008. 3. Group C occupancy special buildings conforming to the limitations specified in Section 450.4.1 of the California Building Code.

  503.2 Ignition-resistant building material. Ignition-resistant building materials shall be designed for exterior use and weather expo- sure and shall comply with any one of the requirements in Section 503.2.1 through 503.2.4.3.3 .

  503.2.1 Noncombustible material. Noncombustible material shall comply with the requirements in Section 501.4 .

  2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 5-3

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  SPECIAL BUILDING CONSTRUCTION REGULATIONS

  503.2.2 Fire-retardant-treated wood. Fire-retardant-treated wood shall be identified for exterior use and shall meet the requirements of Section 2303.2 of the California Building Code .

  503.2.3 Fire-retardant-treated wood roof coverings. Roof assemblies containing fire-retardant-treated wood shingles and shakes shall comply with the requirements of Section 1505.6 of the California Building Code and shall be classified as Class A roof assemblies as required in Section 1505.2 of the California Building Code .

  503.2.4 Other ignition-resistant building material. Material shall be tested on the front and back faces in accordance with the extended ASTM E84 or UL 723 test, for a total test period of 30 minutes, or with the ASTM E2768 test. The materials shall bear identification showing the fire test results. Panel products shall be tested with a ripped or cut longitudinal gap of [1] / 8 inch (3.2 mm). The materials, when tested in accordance with the test procedures set forth in ASTM E84 or UL 723 for a test period of 30 minutes, or with ASTM E2768, shall comply with Sections 503.2.4.1 through 503.2.4.3.

  Exception: Materials composed of a combustible core and a noncombustible exterior covering made from either aluminum at a minimum 0.019 inch (0.48 mm) thickness or corrosion-resistant steel at a minimum 0.0149 inch (0.38 mm) thickness shall not be required to be tested with a ripped or cut longitudinal gap.

• CWUIC § 0.120 High relevance — show source text

  fastener**
  horizontal spacing| |CLADDING FASTENER
  THROUGH FOAM
  SHEATHING INTO:|CLADDING FASTENER
  TYPE AND MINIMUM SIZEc|CLADDING FASTENER
  VERTICAL SPACING
  (INCHES)|Cladding weight:|Cladding weight:|Cladding weight:|Cladding weight:|Cladding weight:|Cladding weight:|Cladding weight:|Cladding weight:| |CLADDING FASTENER
  THROUGH FOAM
  SHEATHING INTO:|CLADDING FASTENER
  TYPE AND MINIMUM SIZEc|CLADDING FASTENER
  VERTICAL SPACING
  (INCHES)|**3 **
  psf|11
  psf|18
  psf|25
  psf|**3 **
  psf|11
  psf|18
  psf|25
  psf| |Wood Framing
  (minimum 11/4- inch
  penetration)b|0.120" diameter nail|6|3.00|1.70|0.90|0.55|3.00|1.05|0.50|DR| |Wood Framing
  (minimum 11/4- inch
  penetration)b|0.120" diameter nail|8|3.00|1.20|0.60|DR|3.00|0.70|DR|DR| |Wood Framing
  (minimum 11/4- inch
  penetration)b|0.120" diameter nail|12|3.00|0.70|DR|DR|2.15|DR|DR|DR| |Wood Framing
  (minimum 11/4- inch
  penetration)b|0.131" diameter nail|6|4.00|2.15|1.20|0.75|4.00|1.35|0.70|DR| |Wood Framing
  (minimum 11/4- inch
  penetration)b|0.131" diameter nail|8|4.00|1.55|0.80|DR|4.00|0.90|DR|DR| |Wood Framing
  (minimum 11/4- inch
  penetration)b|0.131" diameter nail|12|4.00|0.90|DR|DR|2.70|0.50|DR|DR| |Wood Framing
  (minimum 11/4- inch
  penetration)b|0.162" diameter nail|6|4.00|3.55|2.05|1.40|4.00|2.25|1.25|0.80| |Wood Framing
  (minimum 11/4- inch
  penetration)b|0.162" diameter nail|8|4.00|2.55|1.45|0.95|4.00|1.60|0.85|0.50| |Wood Framing
  (minimum 11/4- inch
  penetration)b|0.162" diameter nail|12|4.00|1.60|0.85|0.50|4.00|0.95|DR|DR| |For SI: 1 inch = 25.

• CWUIC § 17.75 High relevance — show source text

  30|17.75|20.83|24.16|27.73|31.55|8.00| |60|45|< 1:12|3.55|3.87|4.54|5.27|6.05|6.88|4.03| |60|45|5:12|4.94|5.37|6.31|7.31|8.40|9.55|6.34| |60|45|7:12|11.71|12.75|14.97|17.36|19.93|22.67|7.39| |60|45|12:12|22.70|24.71|29.00|33.64|38.62|43.94|10.29| |60|60|< 1:12|3.68|4.01|4.71|5.46|6.27|7.13|4.23| |60|60|5:12|5.11|5.57|6.54|7.58|8.70|9.90|7.31| |60|60|7:12|14.38|15.66|18.37|21.31|24.46|27.83|8.71| |60|60|12:12|29.30|31.90|37.44|43.42|49.85|56.72|12.57| |For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s, 1 pound-force per linear foot = 0.146 kN/m, 1 pound per square foot = 47.88 Pa.
  a. Tabulated lengths were derived by calculating design wind pressures in accordance with Figure 28.4-1 of ASCE 7 for a building with a mean roof height of 35 feet, topographic
  factor,Kzt, equal to 1.0, and Risk Category II. For wind perpendicular to the ridge, the effects of a 2-foot overhang on each endwall are included. The design pressures were
  used to calculate forces to be resisted by solid wall segments in each. The forces to be resisted by each wall line were then divided by the default design strength of 840
  pounds per linear foot of length to determine the unreduced length,UR, of solid wall length required in each endwall. The actual mean roof height of the building shall not
  exceed the least horizontal dimension of the building.
  b. Tabulated lengths in the “minimum” column are based on the requirement of Section 28.4.4 of ASCE 7 that the main windforce-resisting system be designed for a minimum
  pressure of 16 psf multiplied by the wall area of the building and 8 psf multiplied by the roof area of the building projected onto a vertical plane normal to the assumed wind
  direction. Tabulated lengths in shaded cells are less than the “minimum” value. Where the minimum controls, it is permitted to be reduced in accordance with Notes c, d and
  e. See Section R608.7.1.1.
  c. For buildings with a mean roof height of less than 35 feet, tabulated lengths are permitted to be reduced by multiplying by the appropriate factor,_R_1, from Table R608.7.1.1(4).
  The reduced length shall be not less than the “minimum” value shown in the table.
  d.