Exterior wall coverings & cladding (R703)

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

• CRC § 7-9 High relevance — show source text

  4, 5, 6,_
  9, 12, 16|Includes Mendocino, Sonoma, Marin, San Francisco, San Mateo, Alameda, Santa Cruz, Monterey, San Benito,
  San Luis Obispo, Santa Barbara, Ventura, San Diego Counties| |_2 _|14, 16|Includes Imperial County| |a. IECC Climate Zones 1, 7 and 8 do not occur in California, nor do any IECC moist climate zones.
  b. IECC boundaries are defined by county political boundary lines. California Energy Code boundaries are based on metes and bounds specifications aligned with climate-affecting
  geographic features, which often do not coincide with county lines.|a. IECC Climate Zones 1, 7 and 8 do not occur in California, nor do any IECC moist climate zones.
  b. IECC boundaries are defined by county political boundary lines. California Energy Code boundaries are based on metes and bounds specifications aligned with climate-affecting
  geographic features, which often do not coincide with county lines.|a. IECC Climate Zones 1, 7 and 8 do not occur in California, nor do any IECC moist climate zones.
  b. IECC boundaries are defined by county political boundary lines. California Energy Code boundaries are based on metes and bounds specifications aligned with climate-affecting
  geographic features, which often do not coincide with county lines.|

  2025 CALIFORNIA RESIDENTIAL CODE 7-9

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

  WALL COVERING

  SECTION R703—EXTERIOR WALL COVERING

  R703.1 General. Exterior walls shall provide the building with a weather-resistant exterior wall envelope. The exterior wall envelope shall include flashing as described in Section R703.4. Exception: Log walls designed and constructed in accordance with the provisions of ICC 400. R703.1.1 Water resistance. The exterior wall envelope shall be designed and constructed in a manner that prevents the accumulation of water within the wall assembly by providing a water-resistive barrier behind the exterior cladding as required by Section R703.2 and a means of draining to the exterior water that penetrates the exterior cladding. Exceptions:

  1. A weather-resistant exterior wall envelope shall not be required over concrete or masonry walls designed in accordance with Chapter 6 and flashed in accordance with Section R703.4 or R703.8.
  2. Compliance with the requirements for a means of drainage, and the requirements of Sections R703.2 and R703.4, shall not be required for an exterior wall envelope that has been demonstrated to resist wind-driven rain through testing of the exterior wall envelope, including joints, penetrations and intersections with dissimilar materials, in accordance with ASTM E331 under the following conditions: 2.1. Exterior wall envelope test assemblies shall include at least one opening, one control joint, one wall/eave interface and one wall sill. All tested openings and penetrations shall be representative of the intended enduse configuration. 2.2. Exterior wall envelope test assemblies shall be at least 4 feet by 8 feet (1219 mm by 2438 mm) in size. 2.3. Exterior wall assemblies shall be tested at a minimum differential pressure of 6.24 pounds per square foot (299 Pa). 2.4. Exterior wall envelope assemblies shall be subjected to the minimum test exposure for a minimum of 2 hours.
• CRC § 48.9 High relevance — show source text

  ** Exterior wall finishes shall be plasters in accordance with Section BJ104.4, or nonplaster exterior wall coverings in accordance with Section R703 and other finish systems complying with all of the following:

  1. With approved specifications and details showing the finish system’s means of attachment to the wall or its independent support, and a means of draining or evaporating water that penetrates the exterior finish to the exterior.
  2. The vapor permeance of the combination of finish materials shall be 5 perms or greater to allow the transpiration of water vapor through the wall.
  3. Finish systems with weights greater than 10 or less than or equal to 20 pounds per square foot (> 48.9 and ≤ 97.8 kg/m) of wall area require a factor of 1.2 for minimum total length of braced wall panels in Table BJ106.13(3).
  4. Finish systems with weights greater than 20 pounds per square foot (97.8 kg/m) of wall area require an engineered design.

  BJ104.2 Purpose, and where required. Strawbale walls shall be finished so as to provide mechanical protection, fire resistance and protection from weather and to restrict the passage of air through the bales, in accordance with this appendix and this code. Vertical strawbale wall surfaces shall receive a coat of plaster not less than [3] / 8 inch (10 mm) thick, or greater where required elsewhere in this appendix, or shall fit tightly against a solid wall panel or dense-packed cellulose insulation with a density of not less than 3.5 pounds per cubic foot (56 kg/m [3] ) blown into an adjacent framed wall. The tops of strawbale walls shall receive a coat of plaster not less than 3 / 8 inch (10 mm) thick or be tightly covered by gypsum board or a roof-bearing assembly.

  Exception: Truth windows shall be permitted where a fire-resistance rating is not required. Weather-exposed truth windows shall be fitted with a weather-tight cover. Interior truth windows in Climate Zones 5, 6, 7, 8 and Marine 4 shall be fitted with an airtight

  cover.

  BJ104.3 Vapor retarders. Class I and II vapor retarders shall not be used on a strawbale wall, nor shall any other material be used that has a vapor permeance rating of less than 5 perms, except as permitted or required elsewhere in this appendix.

  BJ104.4 Plaster. Plaster applied to bales shall be any type described in this section, and as required or limited in this appendix. Plaster thickness shall not exceed 2 inches (51 mm).

  BJ104.4.1 Plaster and membranes. Plaster shall be applied directly to strawbale walls to facilitate transpiration of moisture from the bales, and to secure a mechanical bond between the skin and the bales, except where a membrane is allowed or required elsewhere in this appendix.

  BJ104.4.2 Lath and mesh for plaster. The surface of the straw bales functions as lath, and other lath or mesh shall not be required, except as required for out-of-plane load resistance by Table BJ105.4 or for structural walls by Tables BJ106.12 and BJ106.13(1).

  BJ104.4.3 Clay plaster. Clay plaster shall comply with Sections BJ104.4.3.1 through BJ104.4.3.6.

• CRC § 2.4. High 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 § 5.1.1. High relevance — show source text

  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. Nominal material thicknesses in Table R703.3(1) are based on a maximum stud spacing of 16 inches (406 mm) on center. Where specified by the siding manufacturer’s instructions and supported by a test report or other documentation, attachment to studs with greater spacing is permitted. Fasteners for exterior wall coverings attached to wood framing shall be in accordance with Section R703.3.3 and Table R703.3(1). Exterior wall coverings shall be attached to cold-formed steel light frame construction in accordance with the cladding manufacturer’s installation instructions, the requirements of Table R703.3(1) using screw fasteners substituted for the nails specified in accordance with Table R703.3(2), or an approved design.

  7-10 2025 CALIFORNIA RESIDENTIAL CODE

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  WALL COVERING

  TABLE R703.3(1)—SIDING MINIMUM ATTACHMENT AND MINIMUM THICKNESS	Col2	Col3	Col4	Col5	Col6	Col7	Col8	Col9	Col10
  ** SIDING MATERIAL**	** SIDING MATERIAL**	** NOMINAL** THICKNESS (inches)	** JOINT** TREATMENT	** TYPE OF SUPPORTS FOR THE SIDING MATERIAL AND FASTENERS**	** TYPE OF SUPPORTS FOR THE SIDING MATERIAL AND FASTENERS**	** TYPE OF SUPPORTS FOR THE SIDING MATERIAL AND FASTENERS**	** TYPE OF SUPPORTS FOR THE SIDING MATERIAL AND FASTENERS**	** TYPE OF SUPPORTS FOR THE SIDING MATERIAL AND FASTENERS**	** TYPE

• CRC § 0.42 High relevance — show source text

  = 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.|

  R703.16 Cladding attachment over foam sheathing to cold-formed steel framing. Cladding shall be specified and installed in accordance with Section R703, the cladding manufacturer’s approved instructions, including any limitations for use over foam plastic sheathing, or an approved design. In addition, the cladding or furring attachments through foam sheathing to framing shall meet or exceed the minimum fastening requirements of Section R703.16.1, Section R703.16.2 or an approved design for support of cladding weight.

  Exceptions:

  1. Where the cladding manufacturer has provided approved installation instructions for application over foam sheathing, those requirements shall apply.
  2. For exterior insulation and finish systems, refer to Section R703.9.
  3. For anchored masonry or stone veneer installed over foam sheathing, refer to Section R703.8.

  R703.16.1 Direct attachment. Where cladding is installed directly over foam sheathing without the use of furring, cladding minimum fastening requirements to support the cladding weight shall be as specified in Table R703.16.1.

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  WALL COVERING

  TABLE R703.16.1—CLADDING MINIMUM FASTENING REQUIREMENTS FOR DIRECT ATTACHMENT OVER FOAM PLASTIC SHEATHING TO SUPPORT CLADDING WEIGHTa, b	Col2	Col3	Col4	Col5	Col6	Col7	Col8	Col9	Col10	Col11	Col12	Col13
  ** CLADDING FASTENER** THROUGH FOAM SHEATHING INTO:	**

• 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

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  7-2 2025 CALIFORNIA RESIDENTIAL CODE

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  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 High 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 § 14.3 High relevance — show source text

  Exception: Walls perpendicular to the line used to determine the fire separation distance.

  R703.14.3 Flame spread index. The certification of the flame spread index shall be accompanied by a test report stating that all portions of the test specimen ahead of the flame front remained in position during the test in accordance with ASTM E84 or UL 723.

  R703.15 Cladding attachment over foam sheathing to wood framing. Cladding shall be specified and installed in accordance with Section R703, the cladding manufacturer’s approved instructions, including any limitations for use over foam plastic sheathing, or an approved design. In addition, the cladding or furring attachments through foam sheathing to framing shall meet or exceed the minimum fastening requirements of Section R703.15.1, Section R703.15.2, or an approved design for support of cladding weight.

  Exceptions:

  1. Where the cladding manufacturer has provided approved installation instructions for application over foam sheathing, those requirements shall apply.
  2. For exterior insulation and finish systems, refer to Section R703.9.
  3. For anchored masonry or stone veneer installed over foam sheathing, refer to Section R703.8.

  R703.15.1 Direct attachment. Where cladding is installed directly over foam sheathing without the use of furring, cladding minimum fastening requirements to support the cladding weight shall be as specified in Table R703.15.1.

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  WALL COVERING

  TABLE R703.15.1—CLADDING MINIMUM FASTENING REQUIREMENTS FOR DIRECT ATTACHMENT OVER FOAM PLASTIC SHEATHING TO SUPPORT CLADDING WEIGHTa	Col2	Col3	Col4	Col5	Col6	Col7	Col8	Col9	Col10	Col11	Col12	Col13
  ** CLADDING** FASTENER MINIMUM PENETRATION INTO WOOD **WALL FRAMINGb **	CLADDING FASTENER TYPE AND MINIMUM SIZEc	** CLADDING** FASTENER VERTICAL SPACINGd (inches)	** MAXIMUM THICKNESS OF FOAM SHEATHINGe (inches)**	** MAXIMUM THICKNESS OF FOAM SHEATHINGe (inches)**	** MAXIMUM THICKNESS OF FOAM SHEATHINGe (inches)**	** MAXIMUM THICKNESS OF FOAM SHEATHINGe (inches)**	** MAXIMUM THICKNESS OF FOAM SHEATHINGe (inches)**	** MAXIMUM THICKNESS OF FOAM SHEATHINGe (inches)**	** MAXIMUM THICKNESS OF FOAM SHEATHINGe (inches)**	** MAXIMUM THICKNESS OF FOAM SHEATHINGe (inches)**	** MAXIMUM THICKNESS OF FOAM SHEATHINGe (inches)**	** MAXIMUM THICKNESS OF FOAM SHEATHINGe (inches)**
  **

• CRC § 6-106 High 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 § 14.1.1.2 High relevance — show source text

  R703.14.1.1.2 Under windows and top of walls. Where the nail hem is removed, such as under windows and at the top of walls, nail slot punch or predrilled holes shall be constructed as shown in Figure R703.14.1.1.2 (1).

  FIGURE R703.14.1.1.2 (1)—TYPICAL POLYPROPYLENE SIDING TRIM UNDER WINDOWS AND AT THE TOP OF WALLS

  For SI: 1 inch = 25.4 mm.

  R703.14.1.2 Fastener requirements. Unless otherwise specified in the manufacturer’s installation instructions, nails shall be corrosion resistant, with a minimum 0.120-inch (3 mm) shank and minimum 0.313-inch (8 mm) head diameter. Nails shall be a minimum of 1 [1] / 4 inches (32 mm) long or as necessary to penetrate sheathing or nailable substrate not less than [3] / 4 inch (19.1 mm). Where the nail fully penetrates the sheathing or nailable substrate, the end of the fastener shall extend not less than [1] / 4 inch (6.4 mm) beyond the opposite face of the sheathing or nailable substrate. Spacing of fasteners shall be installed in accordance with the manufacturer’s installation instructions.

  R703.14.2 Fire separation. Polypropylene siding shall not be installed on walls with a fire separation distance of less than 5 feet (1524 mm) and walls closer than 10 feet (3048 mm) to a building on another lot.

  Exception: Walls perpendicular to the line used to determine the fire separation distance.

  R703.14.3 Flame spread index. The certification of the flame spread index shall be accompanied by a test report stating that all portions of the test specimen ahead of the flame front remained in position during the test in accordance with ASTM E84 or UL 723.

  R703.15 Cladding attachment over foam sheathing to wood framing. Cladding shall be specified and installed in accordance with Section R703, the cladding manufacturer’s approved instructions, including any limitations for use over foam plastic sheathing, or an approved design. In addition, the cladding or furring attachments through foam sheathing to framing shall meet or exceed the minimum fastening requirements of Section R703.15.1, Section R703.15.2, or an approved design for support of cladding weight.

  Exceptions:

  1. Where the cladding manufacturer has provided approved installation instructions for application over foam sheathing, those requirements shall apply.
  2. For exterior insulation and finish systems, refer to Section R703.9.
  3. For anchored masonry or stone veneer installed over foam sheathing, refer to Section R703.8.

  R703.15.1 Direct attachment. Where cladding is installed directly over foam sheathing without the use of furring, cladding minimum fastening requirements to support the cladding weight shall be as specified in Table R703.15.1.

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  WALL COVERING

  |TABLE R703.15.1—CLADDING MINIMUM FASTENING REQUIREMENTS FOR
  DIRECT ATTACHMENT OVER FOAM PLASTIC SHEATHING TO SUPPORT CLADDING

• CRC § 6.5 High relevance — show source text

  BJ103.5 Density. Bales shall have a dry density of not less than 6.5 pounds per cubic foot (104 kg/cubic meter). The dry density shall be calculated by subtracting the weight of the moisture in pounds (kg) from the actual bale weight and dividing by the volume of the bale in cubic feet (cubic meters). Not less than 2 percent and not fewer than five bales shall be randomly selected and tested on-site.

  BJ103.6 Partial bales. Partial bales made after original fabrication shall be retied with ties complying with Section BJ103.3.

  2025 CALIFORNIA RESIDENTIAL CODE APPENDIX BJ-5

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

  APPENDIX BJ — STRAWBALE CONSTRUCTION

  BJ103.7 Types of straw. Bales shall be composed of straw from wheat, rice, rye, barley or oat. The dry stems of other cereal grains or similar crops shall be acceptable where approved by the building official. Bales shall not be composed of hay.

  BJ103.8 Orientation of bales. Straw bales shall be placed laid flat, on-edge or on end in accordance with this appendix.

  SECTION BJ104—FINISHES

  BJ104.1 General. Finishes applied to strawbale walls shall comply with this section and with Chapters 3 and 7 unless stated otherwise in this section.

  BJ104.1.1 Exterior wall finishes. Exterior wall finishes shall be plasters in accordance with Section BJ104.4, or nonplaster exterior wall coverings in accordance with Section R703 and other finish systems complying with all of the following:

  1. With approved specifications and details showing the finish system’s means of attachment to the wall or its independent support, and a means of draining or evaporating water that penetrates the exterior finish to the exterior.
  2. The vapor permeance of the combination of finish materials shall be 5 perms or greater to allow the transpiration of water vapor through the wall.
  3. Finish systems with weights greater than 10 or less than or equal to 20 pounds per square foot (> 48.9 and ≤ 97.8 kg/m) of wall area require a factor of 1.2 for minimum total length of braced wall panels in Table BJ106.13(3).
  4. Finish systems with weights greater than 20 pounds per square foot (97.8 kg/m) of wall area require an engineered design.

  BJ104.2 Purpose, and where required. Strawbale walls shall be finished so as to provide mechanical protection, fire resistance and protection from weather and to restrict the passage of air through the bales, in accordance with this appendix and this code. Vertical strawbale wall surfaces shall receive a coat of plaster not less than [3] / 8 inch (10 mm) thick, or greater where required elsewhere in this appendix, or shall fit tightly against a solid wall panel or dense-packed cellulose insulation with a density of not less than 3.5 pounds per cubic foot (56 kg/m [3] ) blown into an adjacent framed wall. The tops of strawbale walls shall receive a coat of plaster not less than 3 / 8 inch (10 mm) thick or be tightly covered by gypsum board or a roof-bearing assembly.

• CRC § 1.1 High 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.