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Chapter 14 — EXTERIOR WALLS

Section 1405 — COMBUSTIBLE MATERIALS ON THE EXTERIOR SIDE OF EXTERIOR WALLS

2025 California Building Code (Title 24, Part 2) · 2025 edition · updated 2026-07-29 · California

Italicized text is a California amendment to the model code, as printed in the official publication.

1405.1 Combustible exterior wall coverings.

Combustible exterior wall coverings shall comply with this section.

Exception: Plastics complying with Chapter 26.

1405.1.1 Types I, II, III and IV-HT construction. On buildings of Types I, II, III and IV-HT construction, exterior wall coverings shall be permitted to be constructed of combustible materials, complying with the following limitations:

  1. Combustible exterior wall coverings shall not exceed 10 percent of an exterior wall surface area where the fire separation distance is 5 feet (1524 mm) or less.
  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

TABLE 1405.1.1.1.2—MINIMUM FIRE SEPARATION FOR COMBUSTIBLE EXTERIOR WALL COVERINGS

FIRE SEPARATION DISTANCE (feet) TOLERABLE LEVEL INCIDENT RADIANT HEAT ENERGY (kW/m2)
5 12.5
6 11.8
7 11.0
8 10.3
9 9.6
10 8.9
11 8.3
12 7.7
13 7.2
14 6.7
15 6.3
16 5.9
17 5.5
18 5.2
19 4.9
20 4.6
21 4.4
22 4.1
23 3.9
24 3.7
25 3.5
For SI: 1 foot = 304.8 mm, 1 Btu/H2 × °F = 0.0057 kW/m2 × K.

1405.1.2 Location. Combustible exterior wall coverings located along the top of exterior walls shall be completely backed up by the exterior wall and shall not extend over or above the top of the exterior wall.

1405.1.3 Fireblocking. Where the combustible exterior wall covering is furred out from the exterior wall and forms a solid surface, the distance between the back of the exterior wall covering and the exterior wall shall not exceed 1 [5] / 8 inches (41 mm). The concealed space thereby created shall be fireblocked in accordance with Section 718. Exception: The distance between the back of the exterior wall covering and the exterior wall shall be permitted to exceed 1 [5] / 8 inches (41 mm) where the concealed space is not required to be fireblocked by Section 718.

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▸ Contents — 2025 California Building Code (Title 24, Part 2)
2025 California Building Code (Title 24, Part 2)
  1. Chapter 1 — ADMINISTRATION
  2. Chapter 2 — DEFINITIONS
  3. Chapter 3 — OCCUPANCY CLASSIFICATION AND USE
  4. Chapter 4 — SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY A…
  5. Chapter 5 — GENERAL BUILDING HEIGHTS AND AREAS
  6. Chapter 6 — TYPES OF CONSTRUCTION
  7. Chapter 7 — FIRE AND SMOKE PROTECTION FEATURES
  8. Chapter 7A — MATERIALS AND CONSTRUCTION METHODS FOR EXTERIOR W…
  9. Chapter 8 — INTERIOR FINISHES
  10. Chapter 9 — FIRE PROTECTION AND LIFE SAFETY SYSTEMS
  11. Chapter 10 — MEANS OF EGRESS
  12. Chapter 11 — RESERVED
  13. Chapter 11A — HOUSING ACCESSIBILITY
  14. Chapter 11B — ACCESSIBILITY TO PUBLIC BUILDINGS, PUBLIC ACCOMM…
  15. Chapter 12 — INTERIOR ENVIRONMENT
  16. Chapter 13 — ENERGY EFFICIENCY
  17. ▸ Chapter 14 — EXTERIOR WALLS
    Overview
    1. Section 1401 — GENERAL
    2. Section 1402 — PERFORMANCE REQUIREMENTS
    3. Section 1403 — MATERIALS
    4. Section 1404 — INSTALLATION OF WALL COVERINGS
    5. Section 1405 — COMBUSTIBLE MATERIALS ON THE EXTERIOR SIDE OF E…
    6. Section 1406 — METAL COMPOSITE MATERIAL (MCM)
    7. Section 1407 — EXTERIOR INSULATION AND FINISH SYSTEMS (EIFS)
    8. Section 1408 — HIGH-PRESSURE DECORATIVE EXTERIOR-GRADE COMPACT…
    9. Section 1409 — INSULATED METAL PANEL (IMP)
    10. Section 1410 — PLASTIC COMPOSITE DECKING
    11. Section 1411 — BUILDING-INTEGRATED PHOTOVOLTAIC (BIPV) SYSTEMS…
    12. Section 1412 — SOFFITS AND FASCIAS AT ROOF OVERHANGS
    13. Section 1413 — [DSA-SS & DSA-SS/CC, OSHPD 1, 1R, 2, 4 & 5] ADD…
  18. Chapter 15 — ROOF ASSEMBLIES AND ROOFTOP STRUCTURES
  19. Chapter 16 — STRUCTURAL DESIGN
  20. Chapter 16A — STRUCTURAL DESIGN
  21. Chapter 17 — SPECIAL INSPECTIONS AND TESTS
  22. Chapter 17A — SPECIAL INSPECTIONS AND TESTS
  23. Chapter 18 — SOILS AND FOUNDATIONS
  24. Chapter 18A — SOILS AND FOUNDATIONS
  25. Chapter 19 — CONCRETE
  26. Chapter 19A — CONCRETE
  27. Chapter 20 — ALUMINUM
  28. Chapter 21 — MASONRY
  29. Chapter 21A — MASONRY
  30. Chapter 22 — STEEL
  31. Chapter 22A — STEEL
  32. Chapter 23 — WOOD
  33. Chapter 24 — GLASS AND GLAZING
  34. Chapter 25 — GYPSUM PANEL PRODUCTS AND PLASTER
  35. Chapter 26 — PLASTIC
  36. Chapter 27 — ELECTRICAL
  37. Chapter 28 — MECHANICAL SYSTEMS
  38. Chapter 29 — PLUMBING SYSTEMS
  39. Chapter 30 — ELEVATORS AND CONVEYING SYSTEMS
  40. Chapter 31 — SPECIAL CONSTRUCTION
  41. Chapter 31A — SYSTEMS FOR WINDOW CLEANING OR EXTERIOR BUILDING…
  42. Chapter 31B — PUBLIC POOLS
  43. Chapter 31C — RADIATION
  44. Chapter 31D — FOOD ESTABLISHMENTS
  45. Chapter 31F — MARINE OIL TERMINALS
  46. Chapter 32 — ENCROACHMENTS INTO THE PUBLIC RIGHT-OF-WAY
  47. Chapter 33 — SAFEGUARDS DURING CONSTRUCTION
  48. Chapter 34 — RESERVED
  49. Chapter 35 — REFERENCED STANDARDS
  50. Appendix A — EMPLOYEE QUALIFICATIONS
  51. Appendix B — BOARD OF APPEALS
  52. Appendix C — GROUP U—AGRICULTURAL BUILDINGS
  53. Appendix D — FIRE DISTRICTS
  54. Appendix E — RESERVED
  55. Appendix F — RODENTPROOFING
  56. Appendix G — FLOOD-RESISTANT CONSTRUCTION
  57. Appendix H — SIGNS
  58. Appendix I — PATIO COVERS
  59. Appendix J — GRADING
  60. Appendix K — GROUP R-3 AND GROUP R-3.1 OCCUPANCIES PROTECTED B…
  61. Appendix L — EARTHQUAKE RECORDING INSTRUMENTATION
  62. Appendix M — TSUNAMI-GENERATED FLOOD HAZARDS
  63. Appendix N — REPLICABLE BUILDINGS
  64. Appendix O — PERFORMANCE-BASED APPLICATION
  65. Appendix P — SLEEPING LOFTS
  66. Appendix Q — EMERGENCY HOUSING

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