General & scope of wall coverings

Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:

• CRC § 7.2 High relevance — show source text

  7|||||||||||||||||||||||| |Table R702.7 (3)||||†|||||||||||||||||||| |R702.7.2||||||||||||||||||||X|||| |Table_R702.7.3_||||||||||||||||||||X||||

  The state agency does not adopt sections identified with the following symbol: †

  2025 CALIFORNIA RESIDENTIAL CODE 7-1

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

  7-2 2025 CALIFORNIA RESIDENTIAL CODE

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

  7 WALL COVERING

  User notes:

  About this chapter: Chapter 7 establishes the various types of materials, materials standards and methods of application permitted as interior and exterior wall coverings. Interior coverings include interior plaster, gypsum board, ceramic tile, wood veneer paneling, hardboard paneling, wood shakes and wood shingles. Exterior wall coverings regulated by this section include aluminum, stone and masonry veneer, wood, hardboard, particleboard, wood structural panel siding, wood shakes and shingles, exterior plaster, steel, vinyl, fiber cement and exterior insulation finish systems. This chapter also contains requirements for the use of vapor retarders for moisture control in walls; wind resistance and water-resistive barriers for exterior wall coverings; and the water-resistive barrier required beneath exterior materials.

  SECTION R701—GENERAL

  R701.1 Application. The provisions of this chapter shall control the design and construction of the interior and exterior wall covering for buildings.

  R701.2 Installation. Products sensitive to adverse weather shall not be installed until adequate weather protection for the installation is provided. Exterior sheathing shall be dry before applying exterior cover.

  SECTION R702—INTERIOR COVERING

  R702.1 General. Interior coverings or wall finishes shall be installed in accordance with this chapter and Tables R702.1(1), R702.1(2), R702.1(3) and R702.3.5. Interior masonry veneer shall comply with the requirements of Section R703.7.1 for support and Section R703.7.4 for anchorage, except an airspace is not required. Interior finishes and materials shall conform to the flame spread and smoke-development requirements of Section R302.9.

  **

  TABLE R702.1(1)—THICKNESS OF PLASTER	Col2	Col3
  ** PLASTER BASE**	** FINISHED THICKNESS OF PLASTER FROM FACE OF LATH, MASONRY, CONCRETE** (inches)	** FINISHED THICKNESS OF PLASTER FROM FACE OF LATH, MASONRY, CONCRETE** (inches)
  ** PLASTER BASE**	** Gypsum Plaster**	** Cement Plaster**
  Expanded metal lath	5/8, minimuma	5/8, minimuma
  Wire lath	5/8, minimuma	3/4, minimum (interior)b
  Wire lath	5/8, minimuma	7/8, minimum (exterior)b
  Gypsum lathg	1/2, minimum	3/4, minimum (interior)b
  Masonry wallsc	1/2, minimum	1/2, minimum
  Monolithic concrete wallsc, d	5/8, maximum	7/8, maximum
  Monolithic concrete ceilingsc, d	3/8,

• CRC § 5-14 Medium relevance — show source text

  Floors (On Ground) . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14

  R505 Cold-Formed Steel Floor Framing . . . . . . . . . . . . . . . 5-14

  R506 Concrete Floors (On Ground) . . . . . . . . . . . . . . . . . . . 5-26

  R507 Exterior Decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-26

  CHAPTER 6 WALL CONSTRUCTION. . . . . . . . . . . . . . . . . . . 6-3

  R601 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

  R602 Wood Wall Framing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

  R603 Cold-Formed Steel Wall Framing. . . . . . . . . . . . . . . . 6-53

  R604 Wood Structural Panels . . . . . . . . . . . . . . . . . . . . . . . . 6-93

  R605 Particleboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-93

  R606 General Masonry Construction. . . . . . . . . . . . . . . . . . 6-93

  R607 Glass Unit Masonry . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-106

  R608 Exterior Concrete Wall Construction. . . . . . . . . . . . 6-107

  R609 Exterior Windows and Doors. . . . . . . . . . . . . . . . . . . 6-172

  R610 Structural Insulated Panel Wall Construction . . . 6-175

  CHAPTER 7 WALL COVERING. . . . . . . . . . . . . . . . . . . . . . . . 7-3

  R701 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

  R702 Interior Covering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

  R703 Exterior Wall Covering . . . . . . . . . . . . . . . . . . . . . . . . . 7-10

  R704 Exterior Soffits and Fascias. . . . . . . . . . . . . . . . . . . . . 7-32

  R705 BIPV Systems for Exterior Wall Coverings and Fenestration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-35

  CHAPTER 8 ROOF-CEILING CONSTRUCTION. . . . . . . . . . . 8-3

• CRC § 6-106 Medium relevance — show source text

  R607 Glass Unit Masonry . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-106

  R608 Exterior Concrete Wall Construction. . . . . . . . . . . . 6-107

  R609 Exterior Windows and Doors. . . . . . . . . . . . . . . . . . . 6-172

  R610 Structural Insulated Panel Wall Construction . . . 6-175

  CHAPTER 7 WALL COVERING. . . . . . . . . . . . . . . . . . . . . . . . 7-3

  R701 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

  R702 Interior Covering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

  R703 Exterior Wall Covering . . . . . . . . . . . . . . . . . . . . . . . . . 7-10

  R704 Exterior Soffits and Fascias. . . . . . . . . . . . . . . . . . . . . 7-32

  R705 BIPV Systems for Exterior Wall Coverings and Fenestration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-35

  CHAPTER 8 ROOF-CEILING CONSTRUCTION. . . . . . . . . . . 8-3

  R801 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

  R802 Wood Roof Framing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

  R803 Roof Sheathing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-30

  R804 Cold-Formed Steel Roof Framing . . . . . . . . . . . . . . . 8-31

  R805 Ceiling Finishes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-44

  R806 Roof Ventilation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-44

  R807 Attic Access. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-46

  CHAPTER 9 ROOF ASSEMBLIES . . . . . . . . . . . . . . . . . . . . . .9-3

  R901 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3

  R902 Fire Classification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3

• CRC § 1.2 Medium relevance — show source text

  1_||X||||||||||||||||||||||| |1403|||X|||||||||||||||||||||| |1404|||X|||||||||||||||||||||| |1404.1.2||||||||X|X|X|X|X||X|X|||||||||| |1404.3.3|||||||||||||||||||||X|||| |1405|||X|||||||||||||||||||||| |1406|||X|||||||||||||||||||||| |1407|||X|||||||||||||||||||||| |1408|||X|||||||||||||||||||||| |1411|||X|||||||||||||||||||||| |1412|||X|||||||||||||||||||||| |1413||||||||X|X|X|X|X||X|X||||||||||

  The state agency does not adopt sections identified with 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.

  2025 CALIFORNIA BUILDING CODE 14-1

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  14-2 2025 CALIFORNIA BUILDING CODE

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  14 EXTERIOR WALLS

  User notes:

  About this chapter: Chapter 14 addresses requirements for exterior walls of buildings. Minimum standards for wall covering materials, such as material performance and fire resistance, installation of wall coverings and the ability of the wall to provide weather protection are provided. This chapter also contains limitations on the areas and heights of combustible wall coverings based on fire separation distances, radiant heat exposure and surface burning characteristics.

  ICC code development note: Code change proposals to sections preceded by the designation [BS] will be considered by the IBC—Structural Code Development

  Committee during the 2025 (Group B) Code Development Cycle.

  SECTION 1401—GENERAL

  1401.1 Scope. The provisions of this chapter shall establish the minimum requirements for exterior walls, exterior wall assemblies, exterior wall coverings, exterior wall openings, exterior windows and doors, exterior soffits and fascias, and architectural trim.

  SECTION 1402—PERFORMANCE REQUIREMENTS

  1402.1 General. The provisions of this section shall apply to exterior walls, exterior wall coverings and components thereof.

  1402.2 Weather protection. Buildings shall be provided with a weather-resistant exterior wall assembly. The exterior wall assembly shall include flashing, as described in Section 1404.4. The exterior wall assembly shall be designed and constructed in such a manner as to prevent the accumulation of water within the exterior wall assembly by providing a water-resistive barrier behind the exterior veneer, as described in Section 1403.2, and a means for draining water that enters the assembly to the exterior. Protection against condensation in the exterior wall assembly shall be provided in accordance with Section 1404.3.

  Exceptions:

  1. A weather-resistant exterior wall assembly shall not be required over concrete or masonry walls designed in accordance with Chapters 19 and 21, respectively.
  2. Compliance with the requirements for a means of drainage, and the requirements of Sections 1403.2 and 1404.4, shall not be required for an exterior wall assembly that has been demonstrated through testing to resist wind-driven rain, including joints, penetrations and intersections with dissimilar materials, in accordance with ASTM E331 under the following conditions:
• CRC § 1401.1 Medium relevance — show source text

  ICC code development note: Code change proposals to sections preceded by the designation [BS] will be considered by the IBC—Structural Code Development

  Committee during the 2025 (Group B) Code Development Cycle.

  SECTION 1401—GENERAL

  1401.1 Scope. The provisions of this chapter shall establish the minimum requirements for exterior walls, exterior wall assemblies, exterior wall coverings, exterior wall openings, exterior windows and doors, exterior soffits and fascias, and architectural trim.

  SECTION 1402—PERFORMANCE REQUIREMENTS

  1402.1 General. The provisions of this section shall apply to exterior walls, exterior wall coverings and components thereof.

  1402.2 Weather protection. Buildings shall be provided with a weather-resistant exterior wall assembly. The exterior wall assembly shall include flashing, as described in Section 1404.4. The exterior wall assembly shall be designed and constructed in such a manner as to prevent the accumulation of water within the exterior wall assembly by providing a water-resistive barrier behind the exterior veneer, as described in Section 1403.2, and a means for draining water that enters the assembly to the exterior. Protection against condensation in the exterior wall assembly shall be provided in accordance with Section 1404.3.

  Exceptions:

  1. A weather-resistant exterior wall assembly shall not be required over concrete or masonry walls designed in accordance with Chapters 19 and 21, respectively.
  2. Compliance with the requirements for a means of drainage, and the requirements of Sections 1403.2 and 1404.4, shall not be required for an exterior wall assembly that has been demonstrated through testing to resist wind-driven rain, including joints, penetrations and intersections with dissimilar materials, in accordance with ASTM E331 under the following conditions:

  The exterior wall design shall be considered to resist wind-driven rain where the results of testing, in accordance with ASTM E331, indicate that water did not penetrate control joints in the exterior wall, joints at the perimeter of openings or intersections of terminations with dissimilar materials.

  2.1. Exterior wall test assemblies shall include not fewer than one opening, one control joint, one wall/eave interface and one wall sill. Tested openings and penetrations shall be representative of the intended end-use configuration. 2.2. Exterior wall test assemblies shall be not less than 4 feet by 8 feet (1219 mm by 2438 mm) in size. 2.3. Exterior wall test assemblies shall be tested at a minimum differential pressure of 6.24 pounds per square foot (0.297 kN/m [2] ). 2.4. Exterior wall test assemblies shall be subjected to a minimum test exposure duration of 2 hours. 3. Exterior insulation and finish systems (EIFS) complying with Section 1407.4.1.

  1402.2.1 [BSC-CG] See California Green Building Standards Code, Chapter 5, Division 5.4 for additional weather protection requirements.

  [BS] 1402.3 Wind resistance. Exterior walls, exterior wall coverings, exterior soffits and fascias, and the associated openings, shall be designed and constructed to resist safely the superimposed loads required by Chapter 16.

• CRC § 1.1 Medium relevance — show source text

  BK104.1 General. Cob walls shall not require a finish, except as required by Section BK104.2. Finishes applied to cob walls shall comply with this section and Chapters 3 and 7 unless stated otherwise in this section.

  BK104.1.1 Interior wall finishes. Where installed, interior wall finishes and interior fire protection shall comply with the applicable provisions of Section R302, and shall be plasters in accordance with Section BK104.4 or nonplaster wall coverings in accordance with Section R702.

  BK104.1.2 Exterior wall finishes. Where installed, exterior wall finishes shall be plasters in accordance with Section BK104.4, nonplaster exterior wall coverings in accordance with Section R703, or other finish systems in accordance with the following:

  1. Specifications and details of the finish system’s attachment to the wall or its independent support and of its means of draining or evaporating water that penetrates the exterior finish shall be approved.

  2. The vapor permeance of the combination of finish materials shall be 5 perms or greater to allow the transpiration of water vapor from the wall.

  3. Finish systems with weights greater than 10 pounds per square foot (48.9 kg/m) and less than or equal to 20 pounds per square foot (97.8 kg/m) of wall area shall require that the minimum total length of cob braced wall panels in Table BK106.11(3) be multiplied by a factor of 1.2.

  4. Finish systems with weights greater than 20 pounds per square foot (97.8 kg/m) of wall area shall require an engineered design.

  BK104.2 Where required. Cob walls exposed to rain due to local climate, building design and wall orientation shall be finished or clad to provide protection from excessive erosion.

  BK104.3 Vapor retarders. Class I and II vapor retarders shall not be used on cob walls, except at cob walls surrounding showers or as required or addressed elsewhere in this appendix.

  BK104.4 Plaster. Plaster applied to cob walls shall be any type described in this section. Plaster thickness shall not exceed 3 inches (76 mm) on each face except with an approved engineered design.

  BK104.4.1 Plaster and membranes. Plaster shall be applied directly to cob walls to facilitate transpiration of moisture from the walls and to secure a mechanical bond between the plaster and the cob and shall comply with Section BK105.4.1.

  BK104.4.2 Plaster lath. The surface of cob walls shall be permitted to function as lath for plaster, with no other lath required. Metal, plastic and natural fiber lath shall be permitted to be used to limit plaster cracking, increase the plaster bond to the wall or to bridge dissimilar materials.

  BK104.4.3 Clay plaster. Clay plaster shall comply with Sections BK104.4.3.1 and BK104.4.3.2.

  BK104.4.3.1 General. Clay plaster shall be any plaster having a clay or clay subsoil binder. Such plaster shall contain sufficient clay to fully bind the sand or other aggregate and any reinforcing fibers. Reinforcing fibers shall be chopped straw, sisal, hemp, animal hair or other similar approved fibers.

  BK104.4.3.2 Clay subsoil requirements. The suitability of clay subsoil shall be determined in accordance with the Figure 2 Ribbon Test and the Figure 3 Ball Test in the appendix of ASTM E2392/E2392M.

• CRC § 2025 Medium relevance — show source text

  The prescriptive provisions of this chapter provide requirements for constructing footings and walls for foundations of wood, masonry, concrete and precast concrete. In addition to a foundation’s ability to support the required design loads, this chapter addresses several other factors that can affect foundation performance. These include controlling surface water and subsurface drainage, requiring soil tests where conditions warrant and evaluating proximity to slopes and minimum depth requirements. The chapter also provides requirements to minimize adverse effects of moisture, decay and pests in basements and crawl spaces.

  Chapter 5 Floors.

  Chapter 5 provides the requirements for the design and construction of floor systems that will be capable of supporting minimum required design loads. This chapter covers four different types: wood floor framing, wood floors on the ground, cold-formed steel floor framing and concrete slabs on the ground. Allowable span tables are provided that greatly simplify the determination of joist, girder and sheathing sizes for raised floor systems of wood framing and cold-formed steel framing. This chapter also contains prescriptive requirements for wood-framed exterior decks and their attachment to the main building.

  Chapter 6 Wall Construction.

  Chapter 6 contains provisions that regulate the design and construction of walls. The wall construction covered in Chapter 6 consists of five different types: wood framed, cold-formed steel framed, masonry, concrete and structural insulated panel (SIP). The primary concern of this chapter is the structural integrity of wall construction and transfer of all imposed loads to the supporting structure. This chapter provides the requirements for the design and construction of wall systems that are capable of supporting the minimum design vertical loads (dead, live and snow loads) and lateral loads (wind or seismic loads). This chapter contains the prescriptive requirements for wall bracing and/or shear walls to resist the imposed lateral loads due to wind and seismic activity.

  Chapter 6 also regulates exterior windows and doors installed in walls. This chapter contains criteria for the performance of exterior windows and doors and includes provisions for testing and labeling, garage doors, windborne debris protection and anchorage details.

  Chapter 7 Wall Covering.

  Chapter 7 contains provisions for the design and construction of interior and exterior wall coverings. This chapter establishes the various types of materials, materials standards and methods of application permitted for use as interior coverings, including interior plaster, gypsum board, ceramic tile, wood veneer paneling, hardboard paneling, wood shakes and wood shingles. Chapter 7 also contains requirements for the use of vapor retarders for moisture control in walls.

  2025 CALIFORNIA RESIDENTIAL CODE xv

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

  Exterior wall coverings provide the weather-resistant exterior envelope that protects the building’s interior from the elements. Chapter 7 provides the requirements for wind resistance and water-resistive barrier for exterior wall coverings. This chapter prescribes the exterior wall coverings as well as the water-resistive barrier required beneath the exterior materials. Exterior wall coverings regulated by this section include aluminum, stone and masonry veneer, wood, hardboard, particleboard, wood structural panel siding, wood shakes and shingles, exterior plaster, steel, vinyl, fiber cement and exterior insulation finish systems.

  Chapter 8 Roof-Ceiling Construction.

• CRC § 2025 Medium relevance — show source text

  Chapter 6 also regulates exterior windows and doors installed in walls. This chapter contains criteria for the performance of exterior windows and doors and includes provisions for testing and labeling, garage doors, windborne debris protection and anchorage details.

  Chapter 7 Wall Covering.

  Chapter 7 contains provisions for the design and construction of interior and exterior wall coverings. This chapter establishes the various types of materials, materials standards and methods of application permitted for use as interior coverings, including interior plaster, gypsum board, ceramic tile, wood veneer paneling, hardboard paneling, wood shakes and wood shingles. Chapter 7 also contains requirements for the use of vapor retarders for moisture control in walls.

  2025 CALIFORNIA RESIDENTIAL CODE xv

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

  Exterior wall coverings provide the weather-resistant exterior envelope that protects the building’s interior from the elements. Chapter 7 provides the requirements for wind resistance and water-resistive barrier for exterior wall coverings. This chapter prescribes the exterior wall coverings as well as the water-resistive barrier required beneath the exterior materials. Exterior wall coverings regulated by this section include aluminum, stone and masonry veneer, wood, hardboard, particleboard, wood structural panel siding, wood shakes and shingles, exterior plaster, steel, vinyl, fiber cement and exterior insulation finish systems.

  Chapter 8 Roof-Ceiling Construction.

  Chapter 8 regulates the design and construction of roof-ceiling systems. This chapter contains two roof-ceiling framing systems: wood framing and cold-formed steel framing. Allowable span tables are provided to simplify the selection of rafter and ceiling joist size for wood roof framing and cold-formed steel framing. Chapter 8 also provides requirements for the application of ceiling finishes, the proper ventilation of concealed spaces in roofs (e.g., enclosed attics and rafter spaces), unvented attic assemblies and attic access.

  Chapter 9 Roof Assemblies.

  Chapter 9 regulates the design and construction of roof assemblies. A roof assembly includes the roof deck, vapor retarder, substrate or thermal barrier, insulation, vapor retarder and roof covering. This chapter provides the requirement for wind resistance of roof coverings.

  The types of roof covering materials and installation regulated by Chapter 9 are: asphalt shingles, clay and concrete tile, metal roof shingles, mineral-surfaced roll roofing, slate and slate-type shingles, wood shakes and shingles, built-up roofs, metal roof panels, modified bitumen roofing, thermoset and thermoplastic single-ply roofing, sprayed polyurethane foam roofing, liquid applied coatings and photovoltaic shingles. Chapter 9 also provides requirements for roof drainage, flashing, above deck thermal insulation, rooftop-mounted photovoltaic systems and recovering or replacing an existing roof covering.

  Chapter 10 Chimneys and Fireplaces.

  Chapter 10 contains requirements for the safe construction of masonry chimneys and fireplaces and establishes the standards for the use and installation of factory-built chimneys, fireplaces and masonry heaters. Chimneys and fireplaces constructed of masonry rely on prescriptive requirements for the details of their construction; the factory-built type relies on the listing and labeling method of approval. Chapter 10 provides the requirements for seismic reinforcing and anchorage of masonry fireplaces and chimneys.

  Chapter 11 [RE] Energy Efficiency.

  Chapter 11 is not adopted in California. See California Energy Code, Title 24, Part 6.

  Chapter 12 Mechanical Administration.

• CRC § 1.1 Medium relevance — show source text

  APPENDIX BK — COB CONSTRUCTION (MONOLITHIC ADOBE)

  BK103.5 Mixing. The clay subsoil, sand and straw for cob shall be thoroughly mixed by manual or mechanical means with water sufficient to produce a mix of a plastic consistency capable of bonding of successively placed layers or lifts.

  BK103.6 Installation. Cob shall be installed on the wall in lifts of a height that supports itself with minimal slumping.

  BK103.7 Dry joints. Each layer of cob shall be prevented from drying until the next layer is installed, to ensure bonding of successive layers. The top of each layer shall be kept moist and malleable with one or more of the following methods:

  1. Covering with a material that prevents loss of or holds moisture.

  2. Covering with a material that shades it from direct sun.

  3. Wetting.

  Where dry joints are unavoidable, the previous layer shall be wetted prior to application of the next layer.

  BK103.8 Drying holes. Where holes to facilitate drying are used, such holes shall be permitted to be of any depth and shall not exceed [3] / 4 inch (19 mm) in diameter. Drying holes shall not be spaced closer than 10 hole-diameters and shall not be placed in braced wall panels. The design load on load-bearing walls with drying holes shall not exceed 90 percent of the allowable bearing capacity as determined in accordance with Section BK106.8. Drying holes shall be filled with cob before final inspection.

  BK103.9 Adding roof loads to walls. Roof and ceiling loads shall not be added until walls are sufficiently dry to support them without compressing.

  SECTION BK104—FINISHES

  BK104.1 General. Cob walls shall not require a finish, except as required by Section BK104.2. Finishes applied to cob walls shall comply with this section and Chapters 3 and 7 unless stated otherwise in this section.

  BK104.1.1 Interior wall finishes. Where installed, interior wall finishes and interior fire protection shall comply with the applicable provisions of Section R302, and shall be plasters in accordance with Section BK104.4 or nonplaster wall coverings in accordance with Section R702.

  BK104.1.2 Exterior wall finishes. Where installed, exterior wall finishes shall be plasters in accordance with Section BK104.4, nonplaster exterior wall coverings in accordance with Section R703, or other finish systems in accordance with the following:

  1. Specifications and details of the finish system’s attachment to the wall or its independent support and of its means of draining or evaporating water that penetrates the exterior finish shall be approved.

  2. The vapor permeance of the combination of finish materials shall be 5 perms or greater to allow the transpiration of water vapor from the wall.

  3. Finish systems with weights greater than 10 pounds per square foot (48.9 kg/m) and less than or equal to 20 pounds per square foot (97.8 kg/m) of wall area shall require that the minimum total length of cob braced wall panels in Table BK106.11(3) be multiplied by a factor of 1.2.

  4. Finish systems with weights greater than 20 pounds per square foot (97.8 kg/m) of wall area shall require an engineered design.

  BK104.2 Where required. Cob walls exposed to rain due to local climate, building design and wall orientation shall be finished or clad to provide protection from excessive erosion.

• CRC § 2.4. Medium relevance — show source text

  2.4. Exterior wall envelope assemblies shall be subjected to the minimum test exposure for a minimum of 2 hours. The exterior wall envelope design shall be considered to resist wind-driven rain where the results of testing indicate that water did not penetrate control joints in the exterior wall envelope, joints at the perimeter of openings penetration or intersections of terminations with dissimilar materials.

  R703.1.2 Wind resistance. Wall coverings, backing materials and their attachments shall be capable of resisting wind loads in accordance with Tables R301.2.1(1) and R301.2.1(2). Wind-pressure resistance of the siding, exterior soffit and backing materials shall be determined by ASTM E330 or other applicable standard test methods. Where wind-pressure resistance is determined by design analysis, data from approved design standards and analysis conforming to generally accepted engineering practice shall be used to evaluate the siding, exterior soffit and backing material and its fastening. All applicable failure modes including bending rupture of siding, fastener withdrawal and fastener head pull-through shall be considered in the testing or design analysis. Where the wall covering, exterior soffit and backing material resist wind load as an assembly, use of the design capacity of the assembly shall be permitted. R703.2 Water-resistive barrier. Not fewer than one layer of water-resistive barrier shall be applied over studs or sheathing of all exterior walls with flashing as indicated in Section R703.4, in such a manner as to provide a continuous water-resistive barrier behind the exterior wall veneer and behind deck ledgers. The water-resistive barrier material shall be continuous to the top of walls and terminated at penetrations and building appendages in a manner to meet the requirements of the exterior wall envelope as described in Section R703.1. Where the water-resistive barrier also functions as a component of a continuous air barrier, the waterresistive barrier shall be installed as an air barrier in accordance with Section N1102.5.1.1. Water-resistive barrier materials shall comply with one of the following:

  1. No. 15 felt complying with ASTM D226, Type 1.

  2. ASTM E2556, Type 1 or 2.

  3. Foam plastic insulating sheathing water-resistive barrier systems complying with Section R703.1.1 and installed in accordance with the manufacturer’s installation instructions.

  4. ASTM E331 in accordance with Section R703.1.1.

  5. Other approved materials in accordance with the manufacturer’s installation instructions. No.15 asphalt felt and water-resistive barriers complying with ASTM E2556 shall be applied horizontally, with the upper layer lapped over the lower layer not less than 2 inches (51 mm), and where joints occur, shall be lapped not less than 6 inches (152 mm). Exception: A water-resistive barrier shall not be required in unconditioned detached tool sheds, storage sheds, playhouses, and other similar accessory structures provided all of the following requirements are met:

  6. Exterior wall covering is limited to siding that is attached direct to studs.

  7. Exterior walls are uninsulated.

  8. Interior side of exterior walls has no wall covering or wall finishes. R703.3 Wall covering nominal thickness and attachments. The nominal thickness and attachment of exterior wall coverings shall be in accordance with Table R703.3(1), the wall covering material requirements of this section, and the wall covering manufacturer’s installation instructions. Cladding attachment over foam sheathing shall comply with the additional requirements and limitations of Sections R703.15 through R703.17.

• CRC § 504.5 Medium relevance — show source text

  504.5 Exterior walls. Exterior walls of buildings or structures shall be constructed with one or more of the following methods, unless they are covered with an exterior wall covering complying with Sections 504.5.2 and 504.5.2.1:

  1. 1-hour fire-resistance-rated construction on the exterior side.

  2. Noncombustible materials.

  3. Heavy timber. Assembly of sawn lumber or glue-laminated wood with the smallest minimum nominal dimension of 4 inches (102 mm). Sawn or glue-laminated planks splined, tongue-and-grove or set close together and well spiked. 4. Log wall construction. 5. Wall assemblies that have been tested in accordance with the test procedures for a 10-minute direct flame contact exposure test set forth in ASTM E2707 with the conditions of acceptance shown in Section 504.9.3. 6. Wall assemblies that meet the performance criteria in accordance with the test procedures for a 10-minute direct flame contact exposure test set forth in SFM Standard 12-7A-1. 7. Wall assemblies suitable for exterior fire exposure containing one layer of [5] / 8 -inch (15.9 mm) Type X gypsum sheathing applied behind the exterior wall covering or cladding on the exterior side of the framing. 8. Wall assemblies suitable for exterior fire exposure with a 1-hour fire-resistance rating, rated from the exterior side, as tested in accordance with ASTM E119 or UL 263.

  9. Fire-retardant-treated wood labeled for exterior use and complying with Section 2303.2 of the California Building Code .

  Such material shall extend from the top of the foundation to the underside of the roof sheathing.

  504.5.1 Flashing. A minimum of 6 inches (152 mm) of metal flashing or noncombustible material applied vertically on the exterior of the wall shall be installed at the ground, decking and roof intersections.

  504.5.2 Exterior wall coverings. Exterior wall coverings shall comply with one or more of the following requirements:

  1. Noncombustible material.

  2. Ignition-resistant building material labeled for exterior use. 3. Fire-retardant-treated wood labeled for exterior use and complying with the requirements of Section 2303.2 of the Califor- nia Building Code. 4. Fire-retardant-treated wood shingles and shakes which have been qualified in accordance with Section 1505.6 of the Cali- fornia Building Code for use as “Class B” roof covering shall be an acceptable alternative wall covering material where installed over solid sheathing.

  Exception: Exterior wall coverings which are a component of an approved wall assembly complying with Section 504.5.

  504.5.2.1 Extent of exterior wall covering. Where provided, exterior wall coverings shall extend from the top of the foundation to the roof, and terminate at 2-inch (50.8 mm) nominal solid wood blocking between rafters at all roof overhangs, or in the case of enclosed eaves, terminate at the enclosure.

  504.6 Underfloor enclosure. Buildings or structures shall have underfloor areas enclosed to the ground with exterior walls in accordance with Section 504.5.

• CRC § 2303.2 Medium relevance — show source text

  2. Combustible exterior wall coverings shall be limited to 40 feet (12 192 mm) in height above grade plane. Exceptions:
  3. Metal composite material (MCM) systems complying with Section 1406.
  4. Exterior insulation and finish systems (EIFS) complying with Section 1407.
  5. High-pressure decorative exterior-grade compact laminate (HPL) systems complying with Section 1408.
  6. Exterior wall coverings containing foam plastic insulation complying with Section 2603.
  7. Combustible exterior wall coverings constructed of fire-retardant-treated wood complying with Section 2303.2 for exterior installation shall not be limited in wall surface area where the fire separation distance is 5 feet (1524 mm) or less and shall be permitted up to 60 feet (18 288 mm) in height above grade plane regardless of the fire separation distance.
  8. Wood veneers shall comply with Section 1404.6.

  1405.1.1.1 Ignition resistance. Where permitted by Section 1405.1.1, combustible exterior wall coverings shall be tested in accordance with NFPA 268.

  Exceptions:

  1. Wood or wood-based products.
  2. Other combustible materials covered with an exterior weather covering, other than vinyl sidings, included in and complying with the thickness requirements of Table 1404.2.
  3. Aluminum having a minimum thickness of 0.019 inch (0.48 mm).

  1405.1.1.1.1 Fire separation 5 feet or less. Where installed on exterior walls having a fire separation distance of 5 feet (1524 mm) or less, combustible exterior wall coverings shall not exhibit sustained flaming as defined in NFPA 268.

  1405.1.1.1.2 Fire separation greater than 5 feet. For fire separation distances greater than 5 feet (1524 mm), any exterior wall covering shall be permitted that has been exposed to a reduced level of incident radiant heat flux in accordance with the NFPA 268 test method without exhibiting sustained flaming. The minimum fire separation distance required for the exterior wall covering shall be determined from Table 1405.1.1.1.2 based on the maximum tolerable level of incident radiant heat flux that does not cause sustained flaming of the exterior wall covering.

  14-16 2025 CALIFORNIA BUILDING CODE

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

  EXTERIOR WALLS