CBC · California Building Code

What does the CBC require for metal composite material (MCM) exterior systems?

MCM exterior panels are allowed in California but must be engineered for wind and weather, meet specified flame and smoke test limits (more stringent on some building types/heights), provide either a 1/2‑inch thermal barrier or approved fire testing for tall/critical installations, and be documented and labeled for code compliance (see CBC § 1406).

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Last reviewed: July 5, 2026

What the code requires — 2–4 sentences

The CBC treats Metal Composite Material (MCM) as a distinct exterior wall covering with performance, fire and structural requirements in Section 1406. In plain terms: MCM systems must be designed for wind and weather, meet specified surface‑burning limits (different limits apply depending on building type and height), provide evidence of required fire‑performance (thermal barrier or approved fire testing) where applicable, and be labeled; the controlling requirements are in § 1406 (see § 1406.1–§ 1406.13).

Requirements in detail

Scope and general provisions

  • MCM materials, construction and quality used as exterior wall coverings are governed by Section 1406; MCM used as cladding, balcony elements or bay/oriel windows must comply with § 1406.4–§ 1406.13.
  • MCM used only as trim/embellishments is subject to the durability and fire‑performance subsections (§ 1406.7–§ 1406.13).

Structural and wind design

  • MCM systems must be designed and constructed to resist component and cladding wind loads per Chapter 16; test results or an engineering analysis verifying compliance must be submitted to the building official. See § 1406.4 and § 1406.5.

Weather resistance and durability

  • MCM systems must meet the weather‑resistance requirements of Chapter 14 (including § 1402) and be constructed to resist wind and rain per the manufacturer’s instructions. See § 1406.6 and § 1406.7.

Fire performance — surface‑burning limits and barriers

  • Two different surface‑burning limits apply:
    • General requirement: flame spread index ≤ 75 and smoke‑developed index ≤ 450 when tested in the maximum thickness intended for use in accordance with ASTM E84 or UL 723 (default). See § 1406.9.
    • For MCM installed on buildings of Types I, II, III and IV within certain heights or above 40 feet, stricter limits apply (see next subsection). See § 1406.10.
  • Where an exterior wall requires a fire‑resistance rating (per § 705), the MCM system must not reduce that rating — evidence must be submitted. See § 1406.8.
  • MCM must be labeled in accordance with Section 1703.5. See § 1406.13.

Special fire rules for Types I–IV construction and height thresholds

  • For buildings of Types I, II, III and IV:
    • Installations up to 40 ft (12,192 mm) above grade plane: MCM must have flame spread ≤ 25 and smoke‑developed ≤ 450 (ASTM E84 / UL 723). See § 1406.10 and § 1406.10.1.
    • Installations greater than 40 ft above grade plane: MCM and the complete MCM system must comply with § 1406.10.1–§ 1406.10.3, including NFPA 285 full‑scale testing of the assembled MCM system. See § 1406.10 and § 1406.10.3.
  • Thermal barrier: For Types I–IV, MCM shall be separated from the interior by an approved thermal barrier consisting of 1/2‑inch (12.7 mm) gypsum wallboard or material meeting NFPA 275 (Temperature Transmission and Integrity tests), unless the system is specifically approved by other fire tests (exceptions below). See § 1406.10.2.

Approved test alternatives and exceptions

  • Exception to the 1/2‑inch thermal barrier: a complete MCM system may be approved based on NFPA 286 testing with the acceptance criteria of CBC Section 803.1.1.1, or by UL 1040 or UL 1715 tests — testing must be with the MCM at the maximum intended thickness and include typical installation details. See § 1406.10.2 (Exceptions).
  • Another exception: MCM used only as balconies, projections, architectural trim or embellishments are not subject to some of the stricter thermal barrier/testing requirements. See § 1406.10 (Exceptions).

Foamed insulation and assemblies

  • If the exterior wall assembly containing the MCM also contains foam plastic insulation, the assembly must comply with the foam‑plastic insulation rules in § 2603 (additional restrictions and tests). See § 1406.12.

Labeling and documentation

  • MCM must be labeled per § 1703.5 and documentation of wind load testing or engineering analysis must be provided to the building official per § 1406.5. See § 1406.5 and § 1406.13.

Decision‑relevant summary table

Requirement / dimension Value / threshold When it applies Code Reference
General surface‑burning limit (flame spread) ≤ 75 Default for MCM § 1406.9
General smoke‑developed index ≤ 450 Default for MCM § 1406.9
Stricter surface‑burning limit (flame spread) ≤ 25 Types I–IV installations (see § 1406.10) § 1406.10.1
Stricter smoke‑developed index ≤ 450 Types I–IV installations § 1406.10.1
Height threshold for additional testing 40 ft (12,192 mm) above grade plane Triggers NFPA 285 / system testing for Types I–IV § 1406.10 and § 1406.10.3
Thermal barrier requirement 1/2‑inch (12.7 mm) gypsum wallboard or equivalent NFPA 275‑tested material Types I–IV unless exception applies § 1406.10.2
Full‑scale system test Must comply with NFPA 285 acceptance criteria MCM systems >40 ft (and for some Type I–IV installations) § 1406.10.3
Alternative fire test acceptance NFPA 286 (with CBC acceptance criteria), UL 1040 or UL 1715 May be used in lieu of thermal barrier if system tested as installed § 1406.10.2 (Exceptions)
Wind load verification Approved tests or engineering analysis must be submitted All MCM systems per Chapter 16 § 1406.5 and § 1406.4

Exceptions & special cases

  • MCM that is part of an exterior wall already required to have a fire‑resistance rating need not comply with § 1406.8 if the MCM attachments do not penetrate through the entire rated wall assembly and the assembly does not contain foam plastic insulation (see the exception in § 1406.8).
  • The thermal‑barrier requirement (1/2‑inch gypsum) can be replaced by system approval based on NFPA 286 (with CBC acceptance criteria), UL 1040, or UL 1715 testing provided the tests are performed with the MCM at maximum intended thickness and include typical installation details. See § 1406.10.2 Exceptions.
  • MCM used only as small trim, embellishments or balcony elements may be treated differently and are specifically excepted from some provisions of § 1406.10. See § 1406.3 and the exceptions in § 1406.10.

If you need the exact test‑report wording a building official will accept, review the applicable NFPA/UL test reports and the manufacturer’s system test documentation — the code requires the tests to be performed with the MCM in the maximum thickness intended for use and including typical seams, joints and attachments. See § 1406.10.2 and § 1406.10.3.

Common mistakes

  • Applying the general flame spread limit (≤ 75) when the project actually requires the stricter ≤ 25 limit for Types I–IV or for installations above 40 ft. Always determine building type and height first. See § 1406.9 and § 1406.10.1.
  • Assuming passing an ASTM E84 (tunnel) test alone satisfies the NFPA 285 requirement — NFPA 285 is a full‑assembly test that may still be required for taller or certain Type I–IV walls. See § 1406.10.3.
  • Omitting submission of wind‑load test results or engineering analysis to the building official. § 1406.5 requires documentation for wind compliance.
  • Forgetting the thermal barrier requirement (1/2‑inch gypsum) or the need for alternate system testing to justify its omission. See § 1406.10.2.
  • Overlooking foam‑plastic insulation rules: if foam plastic is in the wall assembly, Section 2603 requirements also apply. See § 1406.12.
  • Not labeling the MCM as required — labeling per § 1703.5 is mandated by § 1406.13.

Worked example — concrete scenario

Scenario: A Type II office building with MCM cladding running up the façade to 50 ft above grade plane.

  1. Determine the trigger points:

    • Building type: Type II → § 1406.10 applies.
    • Height: 50 ft > 40 ft threshold → stricter testing and system requirements apply. § 1406.10 and § 1406.10.3.

  2. Surface‑burning limits:

    • Choose MCM with ASTM E84 results showing flame spread index ≤ 25 and smoke ≤ 450 (requirement in § 1406.10.1). If the product’s ASTM E84 flame spread is 20 and smoke 300, it meets this limit. § 1406.10.1.

  3. Full‑system fire test:

    • Because the installation is > 40 ft, the assembled MCM system must be tested to the acceptance criteria of NFPA 285 (full‑scale assembly test) and pass (per § 1406.10.3). Provide the NFPA 285 test report showing the actual MCM panels, attachments, joints, insulation (if any) and substrates as installed.

  4. Thermal barrier:

    • Absent an approved NFPA 286/UL 1040/UL 1715 system approval, provide a 1/2‑inch gypsum thermal barrier between the MCM and the interior as required by § 1406.10.2. If using a system approved by NFPA 286 per the CBC acceptance criteria, document that test in lieu of the gypsum.

  5. Wind and weather:

    • Submit approved wind‑load tests or an engineering analysis showing the MCM attachment system and cladding resist the Chapter 16 wind loads (per § 1406.4 and § 1406.5). Also show compliance with weather‑resistance (ASTM E331 test results or manufacturer’s instructions per § 1406.6 and § 1402).

  6. Labeling:

    • Ensure the MCM panels are labeled per § 1703.5 and that labels and documentation are included with submittal (see § 1406.13).

If all of the above is provided and the NFPA 285 test shows compliance, the MCM system will meet the CBC’s § 1406 requirements for this scenario.

Related provisions (quick list)

  • § 1406.1–§ 1406.13 — the full MCM section (general, structural, fire and labeling).
  • § 1406.9 — surface‑burning characteristics (general flame/smoke limits).
  • § 1406.10, § 1406.10.1, § 1406.10.2, § 1406.10.3 — Type I–IV rules, thermal barrier and NFPA 285/full‑scale testing.
  • § 1406.5 and § 1406.4 — wind load design and approval/documentation.
  • § 1406.8 — preservation of required fire‑resistance rating where applicable.
  • § 1406.12 — interaction with foam plastic insulation and Section 2603.
  • § 1406.13 — labeling requirements (see also § 1703.5).
  • § 1402 — overall exterior wall performance requirements referenced by § 1406 (weathering, vertical/lateral flame propagation).

Code references

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

  • CBC § 1405.1.3 High relevance — show source text

    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.

    SECTION 1406—METAL COMPOSITE MATERIAL (MCM)

    1406.1 General. The provisions of this section shall govern the materials, construction and quality of metal composite material (MCM) for use as exterior wall coverings in addition to other applicable requirements of Chapters 14 and 16.

    1406.2 Exterior wall covering. MCM used as exterior wall covering or as elements of balconies and similar projections and bay and oriel windows to provide cladding or weather resistance shall comply with Sections 1406.4 through 1406.13.

    1406.3 Architectural trim and embellishments. MCM used as architectural trim or embellishments shall comply with Sections 1406.7 through 1406.13.

    [BS] 1406.4 Structural design. MCM systems shall be designed and constructed to resist wind loads as required by Chapter 16 for components and cladding.

    1406.5 Approval. Results of approved tests or an engineering analysis shall be submitted to the building official to verify compliance with the requirements of Chapter 16 for wind loads.

    1406.6 Weather resistance. MCM systems shall comply with Section 1402 and shall be designed and constructed to resist wind and rain in accordance with this section and the manufacturer’s installation instructions.

    1406.7 Durability. MCM systems shall be constructed of approved materials that maintain the performance characteristics required in Section 1406 for the duration of use.

    1406.8 Fire-resistance rating. Where MCM systems are used on exterior walls required to have a fire-resistance rating in accordance with Section 705, evidence shall be submitted to the building official that the required fire-resistance rating is maintained.

    Exception: MCM systems that are part of an exterior wall assembly not containing foam plastic insulation and are installed on the outer surface of a fire-resistance-rated exterior wall in a manner such that the attachments do not penetrate through the entire exterior wall assembly, shall not be required to comply with this section.

    2025 CALIFORNIA BUILDING CODE 14-17

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    EXTERIOR WALLS

    1406.9 Surface-burning characteristics. Unless otherwise specified, MCM shall have a flame spread index of 75 or less and a smokedeveloped index of 450 or less when tested in the maximum thickness intended for use in accordance with ASTM E84 or UL 723.

  • CBC § 1406.10 High relevance — show source text

    1406.10 Types I, II, III and IV construction. Where installed on buildings of Types I, II, III and IV construction, metal composite material (MCM) shall comply with Sections 1406.10.1 and 1406.10.2 for installations up to 40 feet (12 192 mm) above grade plane. Where installed on buildings of Type I, II, III and IV construction, MCMs and MCM systems shall comply with Sections 1406.10.1 through 1406.10.3, for installations greater than 40 feet (12 192 mm) above grade plane.

    1406.10.1 Surface-burning characteristics. MCM shall have a flame spread index of not more than 25 and a smoke-developed index of not more than 450 when tested in the maximum thickness intended for use in accordance with ASTM E84 or UL 723.

    1406.10.2 Thermal barriers. MCM shall be separated from the interior of a building by an approved thermal barrier consisting of 1 / 2 -inch (12.7 mm) gypsum wallboard or material that is tested in accordance with and meets the acceptance criteria of both the Temperature Transmission Fire Test and the Integrity Fire Test of NFPA 275.

    Exceptions:

    1. The MCM system is specifically approved based on tests conducted in accordance with NFPA 286 and with the acceptance criteria of Section 803.1.1.1, UL 1040 or UL 1715. Such testing shall be performed with the MCM in the maximum thickness intended for use. The MCM system shall include seams, joints and other typical details used in the installation and shall be tested in the manner intended for use.

    2. The MCM is used as elements of balconies and similar projections, architectural trim or embellishments.

    1406.10.3 Full-scale tests. The MCM system shall be tested in accordance with, and comply with, the acceptance criteria of NFPA 285. Such testing shall be performed on the MCM system with the MCM in the maximum thickness intended for use.

    1406.11 Type V construction. MCM shall be permitted to be installed on buildings of Type V construction.

    1406.12 Foam plastic insulation. Where MCM systems are included in an exterior wall assembly containing foam plastic insulation, the exterior wall assembly shall also comply with the requirements of Section 2603.

    1406.13 Labeling. MCM shall be labeled in accordance with Section 1703.5.

    SECTION 1407—EXTERIOR INSULATION AND FINISH SYSTEMS (EIFS)

    1407.1 General. The provisions of this section shall govern the materials, construction and quality of exterior insulation and finish systems (EIFS) for use as exterior wall coverings in addition to other applicable requirements of Chapters 7, 14, 16, 17 and 26.

    1407.2 Performance characteristics. EIFS shall be constructed such that it meets the performance characteristics required in ASTM E2568.

    [BS] 1407.3 Structural design. The underlying structural framing and substrate shall be designed and constructed to resist loads as required by Chapter 16.

    1407.4 Weather resistance. EIFS shall comply with Section 1402 and shall be designed and constructed to resist wind and rain in accordance with this section and the manufacturer’s application instructions.

  • CBC § 1406.4 High relevance — show source text

    [BS] 1406.4 Structural design. MCM systems shall be designed and constructed to resist wind loads as required by Chapter 16 for components and cladding.

    1406.5 Approval. Results of approved tests or an engineering analysis shall be submitted to the building official to verify compliance with the requirements of Chapter 16 for wind loads.

    1406.6 Weather resistance. MCM systems shall comply with Section 1402 and shall be designed and constructed to resist wind and rain in accordance with this section and the manufacturer’s installation instructions.

    1406.7 Durability. MCM systems shall be constructed of approved materials that maintain the performance characteristics required in Section 1406 for the duration of use.

    1406.8 Fire-resistance rating. Where MCM systems are used on exterior walls required to have a fire-resistance rating in accordance with Section 705, evidence shall be submitted to the building official that the required fire-resistance rating is maintained.

    Exception: MCM systems that are part of an exterior wall assembly not containing foam plastic insulation and are installed on the outer surface of a fire-resistance-rated exterior wall in a manner such that the attachments do not penetrate through the entire exterior wall assembly, shall not be required to comply with this section.

    2025 CALIFORNIA BUILDING CODE 14-17

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    EXTERIOR WALLS

    1406.9 Surface-burning characteristics. Unless otherwise specified, MCM shall have a flame spread index of 75 or less and a smokedeveloped index of 450 or less when tested in the maximum thickness intended for use in accordance with ASTM E84 or UL 723.

    1406.10 Types I, II, III and IV construction. Where installed on buildings of Types I, II, III and IV construction, metal composite material (MCM) shall comply with Sections 1406.10.1 and 1406.10.2 for installations up to 40 feet (12 192 mm) above grade plane. Where installed on buildings of Type I, II, III and IV construction, MCMs and MCM systems shall comply with Sections 1406.10.1 through 1406.10.3, for installations greater than 40 feet (12 192 mm) above grade plane.

    1406.10.1 Surface-burning characteristics. MCM shall have a flame spread index of not more than 25 and a smoke-developed index of not more than 450 when tested in the maximum thickness intended for use in accordance with ASTM E84 or UL 723.

    1406.10.2 Thermal barriers. MCM shall be separated from the interior of a building by an approved thermal barrier consisting of 1 / 2 -inch (12.7 mm) gypsum wallboard or material that is tested in accordance with and meets the acceptance criteria of both the Temperature Transmission Fire Test and the Integrity Fire Test of NFPA 275.

    Exceptions:

    1. The MCM system is specifically approved based on tests conducted in accordance with NFPA 286 and with the acceptance criteria of Section 803.1.1.1, UL 1040 or UL 1715. Such testing shall be performed with the MCM in the maximum thickness intended for use. The MCM system shall include seams, joints and other typical details used in the installation and shall be tested in the manner intended for use.

    2. The MCM is used as elements of balconies and similar projections, architectural trim or embellishments.

  • CBC § 403.4.7 High relevance — show source text

    Smoke exhaust 910 Smoke removal, high-rise buildings 403.4.7 Smokeproof enclosure 909.20.3, 909.20.5, 1023.12 Spray rooms and spaces 416.2.2, 416.3 Stages 410.2.5, 410.2.7 Under-floor ventilation 202.4 Vents, Penetration Protection 714 Vermiculite, Fire Resistant 721 Vertical Opening Protection Atriums 404.6

    Duct penetrations 717.1 Elevators 713.14, 3007.6.1, 3008.6.1 Exceptions 1019, 1023.2 Group I-3 408.5 High-rise 403.2.1.2, 403.2.2, 403.5.1 Live/work units 508.5.6 Open parking garages 406.5.9 Permitted vertical openings 712 Shaft enclosure 713, 1019, 1023.2 Vestibules, Exit Discharge 1028.2 Vinyl Expanded 803.7, 803.8 Rigid 1404.15 Violations 114 Voice Alarm (see Alarms, Voice) Walkway 402.4.3.1, 3104 During construction 3306 Encroachment, public right-of-way 3202.3.4

    Fire resistance Table 601

    Live load Table 1607.1 Materials per construction type Chapter 6 Opening protection 716, 717, 1026.2 Wall, Exterior 705, 1401 Bearing Chapter 6

    California Energy Code and International Energy Conservation Code Climate Zones 1404.3.3 Combustible wall covering 1405 Coverings 1404 Drawings 107.2.4 Exterior insulation and finish systems (EIFS) 1407 Exterior structural members 704.9

    Fire district D102.2.6, D102.1 Fire-resistance ratings 703, 705.5, Table 705.5, 706.5.1, 707.4, 1402.4 Flashing, veneered walls 1404.11.1, 1404.4

    Foam plastic insulation 2603.4.1.4, 2603.5 Glazing, rated 715.8 Joints 705.10, 714 Light-transmitting plastic panels 2607 Materials 705.4, 1403.1, 1405 Metal composite material (MCM) 1406 Nonbearing Chapter 6 Opening protection 705.11, 705.9, 716.2.5.4

    Parapets 705.12 Performance requirements 1402 Projections 705.2 Structural stability 705.7 Vapor retarders 1404.3 Veneer (see Veneer) Weather resistance 1402.2, 1404.2, 1406.6, 1407.4 Weather-resistant barriers 1404.2 Wall, Fire (see Fire Walls) Wall, Foundation (see Foundations) Wall, Interior Finishes 803, 1210.2 Opening protection 716, 717 Wall, Interior Nonbearing (See Partitions) Wall, Masonry 202 Wood Contact 2304.12.1.3,

  • CBC § 1402.4 High relevance — show source text

    1402.4 Fire resistance. Exterior walls shall be fire-resistance rated as required by other sections of this code with opening protection as required by Chapter 7.

    1402.5 Vertical and lateral flame propagation. Exterior walls on buildings of Type I, II, III and IV construction that contain a combustible exterior wall covering, combustible insulation or a combustible water-resistive barrier shall comply with Sections 1402.5.1 through 1402.5.5, as applicable. Where compliance with NFPA 285 and associated acceptance criteria is required in Sections 1402.5.1 through 1402.5.5, the exterior wall assembly shall be tested in accordance with and comply with the acceptance criteria of NFPA 285.

    2025 CALIFORNIA BUILDING CODE 14-3

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    EXTERIOR WALLS

    1402.5.1 Combustible water-resistive barrier. Exterior walls containing a combustible water-resistive barrier shall comply with Section 1402.6.

    1402.5.2 Metal composite material (MCM). Exterior walls containing metal composite material (MCM) systems shall comply with Section 1406.

    1402.5.3 Exterior insulation and finish system (EIFS). Exterior walls containing an exterior insulation and finish system (EIFS) shall comply with Section 1407.

    1402.5.4 High-pressure decorative exterior-grade compact laminate (HPL) system. Exterior walls containing a high-pressure decorative exterior-grade compact laminate (HPL) system shall comply with Section 1408.

    1402.5.5 Foam plastic insulation. Exterior walls containing foam plastic insulation shall comply with Section 2603.

    1402.6 Water-resistive barriers. Exterior walls on buildings of Type I, II, III or IV construction that are greater than 40 feet (12 192 mm) in height above grade plane and contain a combustible water-resistive barrier shall be tested in accordance with and comply with the acceptance criteria of NFPA 285.Combustibility shall be determined in accordance with Section 703.3. For the purposes of this section, fenestration products, flashing of fenestration products and water-resistive-barrier flashing and accessories at other locations, including through wall flashings, shall not be considered part of the water-resistive barrier.

    Exceptions:

    1. Exterior walls in which the water-resistive barrier is the only combustible component and the exterior wall has an exterior wall covering of brick, concrete, stone, terra cotta, stucco or steel with minimum thicknesses in accordance with Table 1404.2.

    2. Exterior walls in which the water-resistive barrier is the only combustible component and the water-resistive barrier complies with the following: 2.1 A peak heat release rate of less than 150 kW/m [2], a total heat release of less than 20 MJ/m [2] and an effective heat of combustion of less than 18 MJ/kg when tested on specimens at the thickness intended for use, in accordance with ASTM E1354, in the horizontal orientation and at an incident radiant heat flux of 50 kW/m [2] .

    2.2 A flame spread index of 25 or less and a smoke-developed index of 450 or less as determined in accordance with ASTM E84 or UL 723, with test specimen preparation and mounting in accordance with ASTM E2404.

  • CBC § 14-3 High relevance — show source text

    1402 Performance Requirements . . . . . . . . . . . . . . . . . . . . 14-3

    1403 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-4

    1404 Installation of Wall Coverings. . . . . . . . . . . . . . . . . . . 14-5

    1405 Combustible Materials on the Exterior Side of

    Exterior Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-16

    1406 Metal Composite Material (MCM). . . . . . . . . . . . . . . 14-17

    1407 Exterior Insulation and Finish Systems (EIFS). . . . 14-18

    1408 High-Pressure Decorative Exterior-Grade Compact Laminates (HPL). . . . . . . . . . . . . . . . . . . 14-18

    1409 Insulated Metal Panel (IMP) . . . . . . . . . . . . . . . . . . . 14-19

    1410 Plastic Composite Decking . . . . . . . . . . . . . . . . . . . . 14-21 1411 Building-Integrated Photovoltaic (BIPV) Systems for Exterior Wall Coverings and Fenestration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-21

    1412 Soffits and Fascias at Roof Overhangs . . . . . . . . . . 14-21

    1413 [DSA-SS & DSA-SS/CC, OSHPD 1, 1R, 2, 4 & 5] Additional Requirements for Anchored and Adhered Veneer. . . . . . . . . . . . . . 14-23

    CHAPTER 15 ROOF ASSEMBLIES AND ROOFTOP

    STRUCTURES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1

    1501 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3

    1502 Roof Drainage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3

    1503 Weather Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3

    1504 Performance Requirements . . . . . . . . . . . . . . . . . . . . 15-3

    1505 Fire Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-5

    1506 Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-6

    1507 Requirements for Roof Coverings . . . . . . . . . . . . . . . 15-7

  • CBC § 2.1. High relevance — show source text

    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.

    [BS] 1402.3.1 Attachments through exterior insulation. Where exterior wall coverings are attached to the building structure through exterior continuous insulation, furring and attachments through the exterior insulation shall be designed to resist design loads determined in accordance with Chapter 16, including support of cladding weight as applicable. Exterior wall coverings attached to the building structure through foam plastic insulating sheathing shall comply with the attachment requirements of Section 1404.5.1, 1404.5.2 or 1404.5.3.

    1402.4 Fire resistance. Exterior walls shall be fire-resistance rated as required by other sections of this code with opening protection as required by Chapter 7.

    1402.5 Vertical and lateral flame propagation. Exterior walls on buildings of Type I, II, III and IV construction that contain a combustible exterior wall covering, combustible insulation or a combustible water-resistive barrier shall comply with Sections 1402.5.1 through 1402.5.5, as applicable. Where compliance with NFPA 285 and associated acceptance criteria is required in Sections 1402.5.1 through 1402.5.5, the exterior wall assembly shall be tested in accordance with and comply with the acceptance criteria of NFPA 285.

    2025 CALIFORNIA BUILDING CODE 14-3

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    EXTERIOR WALLS

    1402.5.1 Combustible water-resistive barrier. Exterior walls containing a combustible water-resistive barrier shall comply with Section 1402.6.

    1402.5.2 Metal composite material (MCM). Exterior walls containing metal composite material (MCM) systems shall comply with Section 1406.

    1402.5.3 Exterior insulation and finish system (EIFS). Exterior walls containing an exterior insulation and finish system (EIFS) shall comply with Section 1407.

  • CBC § 14-16 High relevance — show source text

    14-16 2025 CALIFORNIA BUILDING CODE

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    EXTERIOR WALLS

    TABLE 1405.1.1.1.2—MINIMUM FIRE SEPARATION FOR COMBUSTIBLE EXTERIOR WALL COVERINGS Col2
    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. 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.

    SECTION 1406—METAL COMPOSITE MATERIAL (MCM)

    1406.1 General. The provisions of this section shall govern the materials, construction and quality of metal composite material (MCM) for use as exterior wall coverings in addition to other applicable requirements of Chapters 14 and 16.

    1406.2 Exterior wall covering. MCM used as exterior wall covering or as elements of balconies and similar projections and bay and oriel windows to provide cladding or weather resistance shall comply with Sections 1406.4 through 1406.13.

    1406.3 Architectural trim and embellishments. MCM used as architectural trim or embellishments shall comply with Sections 1406.7 through 1406.13.

    [BS] 1406.4 Structural design. MCM systems shall be designed and constructed to resist wind loads as required by Chapter 16 for components and cladding.

    1406.5 Approval. Results of approved tests or an engineering analysis shall be submitted to the building official to verify compliance with the requirements of Chapter 16 for wind loads.

  • CBC § 12-113 High relevance — show source text

    1248 Reserved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-113

    1249 Reserved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-113

    1250 [CA] Pharmacies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-113

    1251 [CA] Veterinary Premises . . . . . . . . . . . . . . . . . . . . . . 12-113

    1252 [CA] Barber Colleges and Shops. . . . . . . . . . . . . . . . 12-114

    1253 [CA] Schools of Cosmetology, Cosmetological Establishments and Satellite Classrooms . . . . . 12-114

    1254 [CA] Acupuncture Offices . . . . . . . . . . . . . . . . . . . . . . 12-115

    CHAPTER 13 ENERGY EFFICIENCY . . . . . . . . . . . . . . . . . . 13-1

    CHAPTER 14 EXTERIOR WALLS . . . . . . . . . . . . . . . . . . . . . 14-1

    1401 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-3

    1402 Performance Requirements . . . . . . . . . . . . . . . . . . . . 14-3

    1403 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-4

    1404 Installation of Wall Coverings. . . . . . . . . . . . . . . . . . . 14-5

    1405 Combustible Materials on the Exterior Side of

    Exterior Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-16

    1406 Metal Composite Material (MCM). . . . . . . . . . . . . . . 14-17

    1407 Exterior Insulation and Finish Systems (EIFS). . . . 14-18

    1408 High-Pressure Decorative Exterior-Grade Compact Laminates (HPL). . . . . . . . . . . . . . . . . . . 14-18

    1409 Insulated Metal Panel (IMP) . . . . . . . . . . . . . . . . . . . 14-19

    1410 Plastic Composite Decking . . . . . . . . . . . . . . . . . . . . 14-21 1411 Building-Integrated Photovoltaic (BIPV) Systems for Exterior Wall Coverings and Fenestration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-21

  • CBC § 310.4 High relevance — show source text

    Toilet rooms Chapter 29 Lodging Houses 310.4, 310.4.2 Lowest Floor 1603.1.7, 1612.4 Lumber

    General provisions Chapter 23 Quality standards 2303

    Mail Receptacles, Locking 420.13.1 Maintenance Means of egress 1002.1, 3310.2 Property 101.4.4 Mall (see Covered Mall and Open Mall Buildings) Manual Fire Alarm Box 907.4.2

    Manufactured Homes

    Flood resistant G109

    2025 CALIFORNIA BUILDING CODE INDEX-13

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

    INDEX

    Veneer 1403.5, 1404.12 Metal Building System 1705.2.8, Table 1705.2.6, 2210 Metal Composite Material (MCM) 1406 Metal Roof Panel 1504.4.2, 1507.1.1, 1507.4,

    1512.3 Metal Roof Shingle 1504.4.3, 1507.1.1, 1507.5, 1507.5.7, 1512.3 Mezzanines 505 Accessibility Chapters 11A and 11B Area limitations 505.2.1, 505.2.1.1,

    505.3.1

    Egress 505.2.2, 505.2.3, 1009.1 Equipment platforms 505.3 Guards 505.3.3, 1015.1 Height 505.2 Occupant load 1004.2.2 Stairways 712.1.11, 1011.14, 1019, 1023.2 Micropile 1810.3.10, Table 1810.3.2.6, 1810.3.5.2.3, 1810.4.10 Mirrors 1010.1, 2406.1 Mixed Occupancy (see Occupancy Separation) Modifications 104.2.4, 104.4 Modified Bitumen Roof Covering 1507.11 Moisture Protection 1210, 1402.2, 1503 Monasteries 310.3

    Mortar 202

    Ceramic tile 2103.2.3 Dampproofing 1805.2.2 Fire resistance 714.4.1, 715.5 Glass unit masonry 2110.1.1 Masonry 2103.2 Surface-bonding 2103.2.2 Motel 202

    Motels 310.2, 310.3 Motion Picture Projection Rooms 409 Construction 409.2

  • CBC § 2.25 High relevance — show source text

    00|2.25|0.70|DR|3.70|1.05|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|33 mil cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|16|3.85|1.45|DR|DR|3.40|DR|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|33 mil cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|24|3.40|DR|DR|DR|2.70|DR|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#8 Screw|Steel thick-
    ness plus 3
    threads|12|3.00|1.80|DR|DR|3.00|0.65|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#8 Screw|Steel thick-
    ness plus 3
    threads|16|3.00|1.00|DR|DR|2.85|DR|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#8 Screw|Steel thick-
    ness plus 3
    threads|24|2.85|DR|DR|DR|2.20|DR|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|12|4.00|3.85|2.80|1.80|4.00|3.05|1.50|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|16|4.00|3.30|1.95|0.60|4.00|2.25|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|24|4.00|2.25|DR|DR|4.00|0.65|DR|DR| |For SI: 1 inch = 25.4 mm, 1 pound per square foot (psf) = 0.0479 kPa, 1 pound per square inch = 0.00689 MPa.
    DR = Design Required, o.c. = on center.
    a. Wood furring shall be spruce-pine-fir or any softwood species with a specific gravity of 0.42 or greater.

  • CBC § 2.6 High relevance — show source text

    Fire district D102.2.6, D102.1 Fire-resistance ratings 703, 705.5, Table 705.5, 706.5.1, 707.4, 1402.4 Flashing, veneered walls 1404.11.1, 1404.4

    Foam plastic insulation 2603.4.1.4, 2603.5 Glazing, rated 715.8 Joints 705.10, 714 Light-transmitting plastic panels 2607 Materials 705.4, 1403.1, 1405 Metal composite material (MCM) 1406 Nonbearing Chapter 6 Opening protection 705.11, 705.9, 716.2.5.4

    Parapets 705.12 Performance requirements 1402 Projections 705.2 Structural stability 705.7 Vapor retarders 1404.3 Veneer (see Veneer) Weather resistance 1402.2, 1404.2, 1406.6, 1407.4 Weather-resistant barriers 1404.2 Wall, Fire (see Fire Walls) Wall, Foundation (see Foundations) Wall, Interior Finishes 803, 1210.2 Opening protection 716, 717 Wall, Interior Nonbearing (See Partitions) Wall, Masonry 202 Wood Contact 2304.12.1.3,

    2304.12.2.1

    Wall, Parapet 705.12, 1503.3, 2109.2.4.3 Wall, Party (See Fire Walls) Wall, Penetrations 714.4 Wall, Retaining (See Retaining Wall) Wall, Veneered (See Veneer) Chapter 14 Wall, Wood Construction Bracing 2308.10 Cripple walls 2308.9.6 Cutting, notching and boring of dimensional wood framing 2308.6 Exterior framing 2308.9 Fastening schedule Table 2304.10.2 Framing 2304.3, 2308.9 Hillside light-frame construction 2308.2.7 Interior bearing partition 2308.9.4 Interior nonbearing partition 2308.9.1 Openings 2308.9.5 Shear walls 2305.1, 2306.3 Sheathing (see Sheathing) Studs 2308.9.1 Top plates 2308.9.3.2 Waste, Construction 420.12 Water-Reactive Materials Table 307.1(1), 307.4, 307.5. 415.8.4

    Weather Protection

    Exterior walls 1404.2

    Roofs 1503 Welding Materials, verification of steel reinforcement 1705.3.2 Special inspections 1705.13.3, 1705.2, 1705.3.1 Splices of reinforcement in masonry 2107.3, 2108.3 Wildland-Urban Interface 101.4.8

    Wind Load 1609 Basic design wind speed 1609.3 Construction documents

    107, 1603.1.4 Exposure category 1609.4 Glazing 1609.2, 2404 Hurricane 1507.1.1 Masonry,

Frequently asked questions

Do all MCM systems need NFPA 285 testing?

Not always. NFPA 285 full‑assembly testing is required for MCM systems on Types I–IV buildings above the 40 ft threshold and for some installations on those constructions; otherwise, compliance may be demonstrated by meeting the surface‑burning limits and, where applicable, providing the 1/2‑inch thermal barrier or alternate approved system testing (§ 1406.10.1–§ 1406.10.3).

What is the difference between the flame spread limits 75 and 25?

The CBC’s default MCM surface‑burning limit is flame spread ≤ 75 (and smoke ≤ 450) (§ 1406.9). A stricter flame spread ≤ 25 (and smoke ≤ 450) applies for MCM on Types I–IV construction in the contexts described in § 1406.10.1.

Can an NFPA 286 test replace the 1/2‑inch thermal barrier?

Yes — a complete MCM system specifically approved based on NFPA 286 testing (with CBC acceptance criteria) or UL 1040/UL 1715 can be accepted in lieu of the 1/2‑inch gypsum thermal barrier, provided testing is done with MCM at maximum intended thickness and includes typical installation details (§ 1406.10.2 Exceptions).

Do I need to submit wind‑load calculations for MCM?

Yes. § 1406.5 requires submission of approved tests or an engineering analysis to verify compliance with Chapter 16 wind load requirements, and § 1406.4 requires the MCM be designed for those loads.

Is MCM allowed on Type V buildings?

Yes. § 1406.11 permits MCM on Type V construction, but other applicable requirements (fire, weather, wind) still apply.

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