CBC · California Building Code

Roofing & Roof Assemblies

Chapter 15 of the CBC sets the scope, fire classification, material standards and installation rules for roof assemblies and rooftop structures.

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Last reviewed: July 5, 2026

Overview

This hub covers the California Building Code provisions for roof assemblies and rooftop structures — the roof deck, underlayment, coverings, insulation, drainage and related rooftop elements. Chapter 15 establishes the scope and prescriptive requirements that govern design, materials, installation and rooftop structures such as penthouses and raised decks (see §1501 through §1511) .

Fire performance and classification (Class A/B/C) are central to roof safety: Section §1505 sets minimum classifications, testing methods (ASTM E108/UL 790) and Table 1505.1 for required classifications by construction type . Installation and material standards for common coverings — asphalt shingles, single‑ply membranes, metal, tile, sprayed foam, vegetative and photovoltaic systems — appear in the requirements for roof coverings and insulation (notably §1507, §1508) and are tied to wind, drainage and reroofing rules such as §1502 and §1512 .

Practical matters covered here include underlayment and fastener schedules, material standards (ASTM references), rooftop drainage and performance requirements, and special provisions for rooftop equipment, raised decks and rooftop photovoltaics — all aimed at weather protection, fire resistance and structural performance in California’s varied climates and hazard zones .

In this section

Code references

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

  • CBC § 1505.3 High relevance — show source text
    1. Class A roof assemblies include slate installed over ASTM D226, Type II or ASTM D4869, Type IV underlayment over combustible decks.

    [BF] 1505.3 Class B roof assemblies. Class B roof assemblies are those that are effective against moderate fire-test exposure. Class B roof assemblies and roof coverings shall be listed and identified as Class B by an approved testing agency.

    [BF] 1505.4 Class C roof assemblies. Class C roof assemblies are those that are effective against light fire-test exposure. Class C roof assemblies and roof coverings shall be listed and identified as Class C by an approved testing agency.

    [BF] 1505.5 Nonclassified roofing. Nonclassified roofing is approved material that is not listed as a Class A, B or C roof covering assembly or roof covering.

    [BF] 1505.6 Fire-retardant-treated wood shingles and shakes. Fire-retardant-treated wood shakes and shingles are wood shakes and shingles complying with UBC Standard 15-3 or 15-4 which are impregnated by the full-cell vacuum-pressure process with fire-retar- dant chemicals, and which have been qualified by UBC Standard 15-2 or ASTM E108 or UL 790 for use on Class A, B or C roofs.

    Fire-retardant-treated wood shakes and shingles shall comply with ICC-ES EG107 and with the weathering requirements contained in Health and Safety Code Section 13132.7(j). Each bundle shall bear labels from an ICC accredited quality control agency identifying their roof-covering classification and indicating their compliance with ICC-ES EG107 and with the weathering requirements contained in Health and Safety Code Section 13132.7(j).

    Health and Safety Code Section 13132.7(j). No wood roof covering materials shall be sold or applied in this state unless both of the following conditions are met: (1) The materials have been approved and listed by the State Fire Marshal as complying with the requirements of this section. (2) The materials have passed at least five years of the 10-year natural weathering test. The 10-year natural weathering test required by this subdivision shall be conducted in accordance with standard 15-2 of the 1994 edition of the Uniform Building Code at a testing facility recognized by the State Fire Marshal.

    [BF] 1505.7 Special purpose roofs. Special purpose wood shingle or wood shake roofing shall conform to the grading and application requirements of Section 1507.8 or 1507.9. In addition, an underlayment of [5] / 8 -inch (15.9 mm) Type X water-resistant gypsum backing board or gypsum sheathing shall be placed under minimum nominal [1] / 2 -inch-thick (12.7 mm) wood structural panel solid sheathing or 1-inch (25 mm) nominal spaced sheathing.

    [BF] 1505.8 Building-integrated photovoltaic (BIPV) systems. BIPV products installed as the roof covering shall be tested, listed and labeled for fire classification in accordance with Section 1505.1.

    [BF] 1505.9 Rooftop mounted photovoltaic (PV) panel systems. Rooftop mounted photovoltaic (PV) panel systems shall be tested, listed and identified with a fire classification in accordance with UL 2703. Listed systems shall be installed in accordance with the manufacturer’s installation instructions and their listing. The fire classification shall comply with Table 1505.1 based on the type of construction of the building.

  • CBC § 1502.2 High relevance — show source text

    1||||X|X|||||||||||||||||||| |1502.2||||X|X|||||||||||||||||||| |1503.3 – 1503.4|||X|||||||||||||||||||||| |1505 – 1507|||X|||||||||||||||||||||| |1507.3.10||||||||X|X|X|X|X||X|X|||||||||| |1507.7.8||||||||X|X|X|X|X||X|X|||||||||| |1509 – 1511|||X|||||||||||||||||||||| |1511.9.6||||||X|X|||||||||||||||||| |1511.10– 1511.10.1|X|||X|X|||X|X|X|X|X||X|X|||||||||| |1512|||X|||||||||||||||||||||| |1513||||||||X|X|X|X|X||X|X||||||||||

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

    The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.

    2025 CALIFORNIA BUILDING CODE 15-1

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    15-2 2025 CALIFORNIA BUILDING CODE

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    15 ROOF ASSEMBLIES AND ROOFTOP STRUCTURES

    User notes:

    About this chapter: Chapter 15 provides minimum requirements for the design and construction of roof assemblies and rooftop structures. The criteria address the weather-protective barrier at the roof and, in most circumstances, a fire-resistant barrier. The chapter is largely prescriptive in nature and is based on decades of experience with various traditional materials, but it also recognizes newer products. Section 1511 addresses rooftop structures, which include penthouses, tanks, towers and spires. Rooftop penthouses larger than prescribed in this chapter must be treated as a story under Chapter 5.

    ICC code development note: Code change proposals to sections preceded by the designation [BF] or [P] will be considered by one of the code development committees meeting during the 2024 (Group A) Code Development Cycle. All other code change proposals will be considered by a code development committee meeting during the 2025 (Group B) Code Development Cycle.

    SECTION 1501—GENERAL

    1501.1 Scope. The provisions of this chapter shall govern the design, materials, construction and quality of roof assemblies, and rooftop structures.

    SECTION 1502—ROOF DRAINAGE

    [P] 1502.1 General. Design and installation of roof drainage systems shall comply with this section, Section 1611 of this code and Chapter 11 of the California Plumbing Code .

    [P] 1502.2 Secondary (emergency overflow) drains or scuppers. Where roof drains are required, secondary (emergency overflow) roof drains or scuppers shall be provided where the roof perimeter construction extends above the roof in such a manner that water will be entrapped if the primary drains allow buildup for any reason. The installation and sizing of secondary emergency overflow drains, leaders and conductors shall comply with Section 1611 of this code and Chapter 11 of the California Plumbing Code .

  • CBC § 1505.1.1 High relevance — show source text

    ROOF ASSEMBLIES AND ROOFTOP STRUCTURES

    1505.1.1 Roofing requirements within Fire Hazard Severity Zones or in the Wildland-Urban Interface (WUI). Roofing require- ments for structures located within Fire Hazard Severity Zones or in the Wildland-Urban Interface (WUI) shall also comply with Section 705A.

    1505.1.2 Roof coverings within all other areas other than Fire Hazard Severity Zones or a Wildland-Urban Interface (WUI). The entire roof covering of every existing structure where more than 50 percent of the total roof area is replaced within any one-year period, the entire roof covering of every new structure, and any roof covering applied in the alteration, repair or replacement of the roof of every existing structure, shall be a fire-retardant roof covering that is at least Class C fire classification.

    [BF] 1505.2 Class A roof assemblies. Class A roof assemblies are those that are effective against severe fire test exposure. Class A roof assemblies and roof coverings shall be listed and identified as Class A by an approved testing agency. Class A roof assemblies shall be permitted for use in buildings or structures of all types of construction.

    Exceptions:

    1. Class A roof assemblies include those with coverings of brick, masonry or an exposed concrete roof deck.

    2. Class A roof assemblies also include ferrous or copper shingles or sheets, metal sheets and shingles, clay or concrete roof tile or slate installed on noncombustible decks or ferrous, copper or metal sheets installed without a roof deck on noncombustible framing.

    3. Class A roof assemblies include minimum 16 ounce per square foot (0.0416 kg/m [2] ) copper sheets installed over combustible decks.

    4. Class A roof assemblies include slate installed over ASTM D226, Type II or ASTM D4869, Type IV underlayment over combustible decks.

    [BF] 1505.3 Class B roof assemblies. Class B roof assemblies are those that are effective against moderate fire-test exposure. Class B roof assemblies and roof coverings shall be listed and identified as Class B by an approved testing agency.

    [BF] 1505.4 Class C roof assemblies. Class C roof assemblies are those that are effective against light fire-test exposure. Class C roof assemblies and roof coverings shall be listed and identified as Class C by an approved testing agency.

    [BF] 1505.5 Nonclassified roofing. Nonclassified roofing is approved material that is not listed as a Class A, B or C roof covering assembly or roof covering.

    [BF] 1505.6 Fire-retardant-treated wood shingles and shakes. Fire-retardant-treated wood shakes and shingles are wood shakes and shingles complying with UBC Standard 15-3 or 15-4 which are impregnated by the full-cell vacuum-pressure process with fire-retar- dant chemicals, and which have been qualified by UBC Standard 15-2 or ASTM E108 or UL 790 for use on Class A, B or C roofs.

    Fire-retardant-treated wood shakes and shingles shall comply with ICC-ES EG107 and with the weathering requirements contained in Health and Safety Code Section 13132.7(j). Each bundle shall bear labels from an ICC accredited quality control agency identifying their roof-covering classification and indicating their compliance with ICC-ES EG107 and with the weathering requirements contained in Health and Safety Code Section 13132.7(j).

  • CBC § 1.0 High relevance — show source text

    Extrapolation is not permitted.
    c. Basic wind speed,V, and wind exposure shall be determined in accordance with Section 1609.
    d. Where the minimum required parapet height is indicated to be 2 inches (51 mm), a gravel stop shall be permitted and shall extend not less than 2 inches (51 mm) from the roof
    surface and not less than the height of the aggregate.
    e. The tabulated values apply only to conditions where the topographic factor (Kzt) determined in accordance with Chapter 26 of ASCE 7 is 1.0 or where_Kzt_ is incorporated in the
    basic wind speed in Section 1609.
    f. For Exposure D, add 8 inches (203 mm) to the parapet height required for Exposure C and the parapet height shall not be less than 12 inches (305 mm).|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s.
    a. Parapet height is measured vertically from the top surface of the coping down to the surface of the roof covering in the field of the roof adjacent to the parapet and outbound
    of any cant strip.
    b. Interpolation shall be permitted for wind speed, mean roof height and parapet height. Extrapolation is not permitted.
    c. Basic wind speed,V, and wind exposure shall be determined in accordance with Section 1609.
    d. Where the minimum required parapet height is indicated to be 2 inches (51 mm), a gravel stop shall be permitted and shall extend not less than 2 inches (51 mm) from the roof
    surface and not less than the height of the aggregate.
    e. The tabulated values apply only to conditions where the topographic factor (Kzt) determined in accordance with Chapter 26 of ASCE 7 is 1.0 or where_Kzt_ is incorporated in the
    basic wind speed in Section 1609.
    f. For Exposure D, add 8 inches (203 mm) to the parapet height required for Exposure C and the parapet height shall not be less than 12 inches (305 mm).|

    SECTION 1505—FIRE CLASSIFICATION

    [BF] 1505.1 General. Fire classification of roof assemblies shall be in accordance with Section 1505. The minimum fire classification of roof assemblies installed on buildings shall comply with Table 1505.1 based on type of construction of the building. Class A, B and C roof assemblies and roof coverings required to be listed by this section shall be tested in accordance with ASTM E108 or UL 790. In addition, fire-retardant-treated woodroof coverings shall be tested in accordance with ASTM D2898; fire-retardant-treated shingles and shakes shall comply with Section 1505.6.

    Exception: Skylights and sloped glazing that comply with Chapter 24 or Section 2610.

  • CBC § 1507.12.2 High relevance — show source text
    TABLE 1507.12.2—SINGLE-PLY ROOFING MATERIAL STANDARDS Col2
    MATERIAL MATERIAL STANDARD
    Chlorosulfonated polyethylene (CSPE) or polyisobutylene (PIB) ASTM D5019
    Ethylene propylene diene monomer (EPDM) ASTM D4637
    Ketone Ethylene Ester (KEE) ASTM D6754
    Polyvinyl Chloride (PVC) or (PVC/KEE) ASTM D4434
    Thermoplastic polyolefin (TPO) ASTM D6878

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    ROOF ASSEMBLIES AND ROOFTOP STRUCTURES

    1507.12.3 Ballasted low-slope roofs. Ballasted low-slope roofs shall be installed in accordance with this section and Section 1504.5. Stone used as ballast shall comply with ASTM D448 or ASTM D7655.

    1507.13 Sprayed polyurethane foam roofing. The installation of sprayed polyurethane foam roofing shall comply with the provisions of this section.

    1507.13.1 Slope. Sprayed polyurethane foam roofs shall have a design slope of not less than [1] / 4 unit vertical in 12 units horizontal (2-percent slope) for drainage.

    1507.13.2 Material standards. Spray-applied polyurethane foam insulation shall comply with ASTM C1029 Type III or IV or ASTM D7425.

    1507.13.3 Application. Foamed-in-place roof insulation shall be installed in accordance with the manufacturer’s instructions. A liquid-applied protective coating that complies with Table 1507.13.3 shall be applied not less than 2 hours nor more than 72 hours following the application of the foam.

    TABLE 1507.13.3—PROTECTIVE COATING MATERIAL STANDARDS Col2
    MATERIAL STANDARD
    Acrylic coating ASTM D6083
    Silicone coating ASTM D6694
    Moisture-cured polyurethane coating ASTM D6947

    1507.13.4 Foam plastics. Foam plastic materials and installation shall comply with Chapter 26.

    1507.14 Liquid-applied roofing. The installation of liquid-applied roofing shall comply with the provisions of this section. 1507.14.1 Slope. Liquid-applied roofing shall have a design slope of not less than [1] / 4 unit vertical in 12 units horizontal (2-percent slope).

    1507.14.2 Material standards. Liquid-applied roofing shall comply with ASTM C836, ASTM C957 or ASTM D3468.

    1507.14.3 Application. Liquid-applied roofing shall be installed in accordance with this chapter and the manufacturer’s installation instructions.

    1507.15 Vegetative roofs and landscaped roofs. Vegetative roofs and landscaped roofs shall comply with the requirements of this chapter, Section 1607.14 and the California Fire Code.

    [BF] 1507.15.1 Structural fire resistance. The structural frame and roof construction supporting the load imposed on the roof by the vegetative roof or landscaped roofs shall comply with the fire-resistance-rating requirements of Table 601.

  • CBC § 1.0 High relevance — show source text

    Interpolation shall be permitted for wind speed, mean roof height and parapet height. Extrapolation is not permitted.
    c. Basic wind speed,V, and wind exposure shall be determined in accordance with Section 1609.
    d. Where the minimum required parapet height is indicated to be 2 inches (51 mm), a gravel stop shall be permitted and shall extend not less than 2 inches (51 mm) from the roof
    surface and not less than the height of the aggregate.
    e. The tabulated values apply only to conditions where the topographic factor (Kzt) determined in accordance with Chapter 26 of ASCE 7 is 1.0 or where_Kzt_ is incorporated in the
    basic wind speed in Section 1609.
    f. For Exposure D, add 8 inches (203 mm) to the parapet height required for Exposure C and the parapet height shall not be less than 12 inches (305 mm).|

    SECTION 1505—FIRE CLASSIFICATION

    [BF] 1505.1 General. Fire classification of roof assemblies shall be in accordance with Section 1505. The minimum fire classification of roof assemblies installed on buildings shall comply with Table 1505.1 based on type of construction of the building. Class A, B and C roof assemblies and roof coverings required to be listed by this section shall be tested in accordance with ASTM E108 or UL 790. In addition, fire-retardant-treated woodroof coverings shall be tested in accordance with ASTM D2898; fire-retardant-treated shingles and shakes shall comply with Section 1505.6.

    Exception: Skylights and sloped glazing that comply with Chapter 24 or Section 2610.

    [BF] TABLE 1505.1—MINIMUM ROOF ASSEMBLY CLASSIFICATION FOR TYPES OF CONSTRUCTIONa, b Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9
    IA IB IIA IIB IIIA IIIB IV VA VB
    B B B Cc B Cc B B Cc
    For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929 m2.
    a. Unless otherwise required in accordance with the_California Wildland-Urban Interface Code_ or due to the location of the building within a fire district in accordance with
    Appendix D.
    b. Nonclassified roof coverings shall be permitted on buildings of Group U occupancies, where there is a minimum fire-separation distance of 6 feet measured from the leading
    edge of the roof.
    c. Buildings that are not more than two stories above grade plane and having not more than 6,000 square feet of projected roof area and where there is a minimum 10-foot fire-
    separation distance from the leading edge of the roof to a lot line on all sides of the building, except for street fronts or public ways, shall be permitted to have roofs of No. 1
    cedar or redwood shakes and No. 1 shingles constructed in accordance with Section 1505.7.    		 For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929 m2.
    a. Unless otherwise required in accordance with the_California Wildland-Urban Interface Code_ or due to the location of the building within a fire district in accordance with
    Appendix D.
    b.
  • CBC § 4.1 High relevance — show source text

    1|||X||||||||||||||||||||| |R902.1 - R902.4|||X||||||||||||||||||||| |R903.4.1||||X|||||||||||||||||||| |R904.1 - R904.4|||X||||||||||||||||||||| |R905.15||||X|||||||||||||||||||| |R905.16||||X|||||||||||||||||||| |R907.1||||X|||||||||||||||||||| |R907.2 – R907.5|||X||||||||||||||||||||| |R909|||X|||||||||||||||||||||

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

    2025 CALIFORNIA RESIDENTIAL CODE 9-1

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    9-2 2025 CALIFORNIA RESIDENTIAL CODE

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    9 ROOF ASSEMBLIES

    User notes:

    About this chapter: Chapter 9 addresses the design and construction of roof assemblies. A roof assembly includes the roof deck, 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 addressed 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 building-integrated photovoltaic (BIPV) roof coverings. 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.

    SECTION R901—GENERAL

    R901.1 Scope. The provisions of this chapter shall govern the design, materials, construction and quality of roof assemblies.

    SECTION R902—FIRE CLASSIFICATION

    R902.1 Roof assemblies. Roof decks shall be covered with materials as set forth in Section R904 or with roof coverings as set forth in Section R905. A minimum Class A, B or C roofing shall be installed in areas designated by this section or where the edge of the roof deck is less than 3 feet (914 mm) from a lot line. Where Class A, B or C roof assemblies are required, they shall be tested in accordance with ASTM E108 or UL 790. Where required, the roof assembly shall be listed and identified as to class by an approved testing agency.

    Exceptions:

    1. Class A roof assemblies include those with coverings of brick, masonry and exposed concrete roof deck.

    2. Class A roof assemblies include ferrous or copper shingles or sheets, metal sheets and shingles, clay or concrete roof tile, or slate installed on noncombustible roof decks or ferrous, copper or metal sheets installed without a roof deck on noncombustible framing.

    3. Class A roof assemblies include minimum 16 ounces per square foot (4.882 kg/m [2] ) copper sheets installed over combustible roof decks.

    4. Class A roof assemblies include slate installed over underlayment over ASTM D226, Type II underlayment over combustible decks.

  • CBC § 14-23 Medium relevance — show source text

    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

    1508 Roof Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15-20

    1509 Roof Coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15-20

    1510 Radiant Barriers Installed Above Deck . . . . . . . . . .15-21

    1511 Rooftop Structures . . . . . . . . . . . . . . . . . . . . . . . . . . .15-21

    1512 Reroofing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15-24

    1513 [DSA-SS & DSA-SS/CC, OSHPD 1, 1R, 2, 4 & 5] Seismic Anchorage of Slate Shingle, Clay and Concrete Tile Roof Coverings. . . . . . . 15-25

    INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INDEX-1

    HISTORY NOTE TO VOLUME 1 . . . . . . . . . . . . . . . . . . . . . .HIST-1

    VOLUME 2

    CHAPTER 16 STRUCTURAL DESIGN . . . . . . . . . . . . . . . . . .16-1

  • CBC § 9-16 Medium relevance — show source text

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    ROOF ASSEMBLIES

    TABLE R905.11.2—MODIFIED BITUMEN ROOFING MATERIAL STANDARDS Col2
    ** MATERIAL** ** STANDARD**
    Acrylic coating ASTM D6083
    Asphalt adhesive ASTM D3747
    Asphalt cement ASTM D3019
    Asphalt coating ASTM D1227; D2824
    Asphalt primer ASTM D41
    Modified bitumen roof membrane ASTM D6162; D6163; D6164; D6222; D6223; D6298

    R905.11.2.1 Base sheet. A base sheet that complies with the requirements of Section 1507.11.2 of the California Building Code, ASTM D1970 or ASTM D4601 shall be permitted to be used with a modified bitumen cap sheet.

    R905.11.3 Application. Modified bitumen roofs shall be installed in accordance with this chapter and the manufacturer’s instructions.

    R905.11.4 Wind resistance of modified bitumen roofing. Modified bitumen roofing shall be tested in accordance with FM 4474, UL 580 or UL 1897 and installed to resist the component and cladding loads specified in Table R301.2.1(1), adjusted for height and exposure in accordance with Table R301.2.1(2).

    R905.12 Single-ply roofing. The installation of single-ply membrane roof coverings shall comply with the provisions of this section.

    TABLE R905.12—SINGLE-PLY ROOFING MATERIAL STANDARDS Col2
    MATERIAL STANDARD
    Chlorosulfanated polyethylene (CSPE) or polyisobutylene (PIB) ASTM D5019
    Ethylene propylene diene monomer (EPDM) ASTM D4637
    Ketone Ethylene Ester (KEE) ASTM D6754
    Polyvinyl chloride (PVC) or (PVC/KEE) ASTM D4434
    Thermosplastic polyolefin (TPO) ASTM D6878

    R905.12.1 Slope. Single-ply membrane roof coverings shall have a design slope of not less than [1] / 4 unit vertical in 12 units horizontal (2-percent slope) for drainage.

    R905.12.2 Material standards. Single-ply membrane roof coverings shall comply with the material standards in Table R905.12.

    R905.12.3 Application. Single-ply membrane roof coverings shall be installed in accordance with this chapter and the manufacturer’s installation instructions.

    R905.12.4 Wind resistance of single-ply roofing. Single-ply roofing shall be tested in accordance with FM 4474, UL 580 or UL 1897 and installed to resist the component and cladding loads specified in Table R301.2.1(1), adjusted for height and exposure in accordance with Table R301.2.1(2).

    R905.13 Sprayed polyurethane foam roofing. The installation of sprayed polyurethane foam roofing shall comply with the provisions of this section.

  • CBC § 14-3 Medium 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 § 1507.11 Medium relevance — show source text

    Type I or II| |Coal-tar primer used in roofing, dampproofing and waterproofing|ASTM D43| |Glass mat, coal-tar|ASTM D4990| |Glass mat, venting type|ASTM D4897| |Mineral-surfaced inorganic cap sheet|ASTM D3909| |Thermoplastic fabrics used in roofing|ASTM D5665, D5726|

    1507.11 Modified bitumen roofing. The installation of modified bitumen roofing shall comply with the provisions of this section. 1507.11.1 Slope. Modified bitumen roofing shall have a design slope of not less than [1] / 4 unit vertical in 12 units horizontal (2percent slope) for drainage.

    1507.11.2 Material standards. Modified bitumen roofing materials shall comply with ASTM D6162, ASTM D6163, ASTM D6164, ASTM D6222, ASTM D6223, ASTM D6298 or ASTM D6509.

    1507.11.2.1 Base sheet. A base sheet that complies with the requirements of Section 1507.11.2, ASTM D1970 or ASTM D4601 shall be permitted to be used with a modified bitumen cap sheet.

    1507.12 Single-ply roofing. The installation of single-ply roofing shall comply with the provisions of this section. 1507.12.1 Slope. Single-ply membrane roofs shall have a design slope of not less than [1] / 4 unit vertical in 12 units horizontal (2-percent slope) for drainage.

    1507.12.2 Material standards. Single-ply roof coverings shall comply with the material standards in Table 1507.12.2.

    TABLE 1507.12.2—SINGLE-PLY ROOFING MATERIAL STANDARDS Col2
    MATERIAL MATERIAL STANDARD
    Chlorosulfonated polyethylene (CSPE) or polyisobutylene (PIB) ASTM D5019
    Ethylene propylene diene monomer (EPDM) ASTM D4637
    Ketone Ethylene Ester (KEE) ASTM D6754
    Polyvinyl Chloride (PVC) or (PVC/KEE) ASTM D4434
    Thermoplastic polyolefin (TPO) ASTM D6878

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    ROOF ASSEMBLIES AND ROOFTOP STRUCTURES

    1507.12.3 Ballasted low-slope roofs. Ballasted low-slope roofs shall be installed in accordance with this section and Section 1504.5. Stone used as ballast shall comply with ASTM D448 or ASTM D7655.

    1507.13 Sprayed polyurethane foam roofing. The installation of sprayed polyurethane foam roofing shall comply with the provisions of this section.

    1507.13.1 Slope. Sprayed polyurethane foam roofs shall have a design slope of not less than [1] / 4 unit vertical in 12 units horizontal (2-percent slope) for drainage.

    1507.13.2 Material standards. Spray-applied polyurethane foam insulation shall comply with ASTM C1029 Type III or IV or ASTM D7425.

  • CBC § 1512.2 Medium relevance — show source text

    1512.2 Roof replacement. Roof replacement shall include the removal of all existing layers of roof assembly materials down to the roof deck.

    Exceptions:

    1. Where the existing roof assembly includes an ice barrier membrane that is adhered to the roof deck and the existing sheathing is not water-soaked or deteriorated to the point that it is not adequate as a base for additional roofing, the existing ice barrier membrane shall be permitted to remain in place and covered with an additional layer of ice barrier membrane in accordance with Section 1507 where permitted by the roof covering manufacturer and new ice barrier underlayment manufacturer.
    2. Where the existing roof includes a self-adhered underlayment and the existing sheathing is not water-soaked or deteriorated to the point that it is not adequate as a base for additional roofing, the existing self-adhered underlayment shall be permitted to remain in place and covered with an underlayment complying with Tables 1507.1.1(1), 1507.1.1(2) and 1507.1.1(3).
    3. Where the existing roof includes one layer of self-adhered underlayment and the existing layer cannot be removed without damaging the roof deck, a second layer of self-adhered underlayment is permitted to be installed over the existing self-adhered underlayment provided that the following conditions are met: 3.1. It is permitted by the roof covering manufacturer and self-adhered underlayment manufacturer. 3.2. The existing sheathing is not water-soaked or deteriorated to the point that it is not adequate as a base for additional roofing.

    15-24 2025 CALIFORNIA BUILDING CODE

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    ROOF ASSEMBLIES AND ROOFTOP STRUCTURES

    3.3. The second layer of self-adhered underlayment is installed such that buildup of material at walls, valleys, roof edges, end laps and side laps does not exceed two layers.

    1512.3 Roof recover. The installation of a new roof covering over an existing roof covering shall be permitted where any of the following conditions occur:

    1. Where the new roof covering is installed in accordance with the roof covering manufacturer’s approved instructions.
    2. Complete and separate roofing systems, such as standing-seam metal roof panel systems, that are designed to transmit the roof loads directly to the building’s structural system and that do not rely on existing roofs and roof coverings for support, shall not require the removal of existing roof coverings.
    3. Metal panel, metal shingle and concrete and clay tile roof coverings shall be permitted to be installed over existing wood shake roofs when applied in accordance with Section 1512.3.1.
    4. The application of a new protective roof coating over an existing protective roof coating, metal roof panel, built-up roof, spray polyurethane foam roofing system, metal roof shingles, mineral-surfaced roll roofing, modified bitumen roofing or thermoset and thermoplastic single-ply roofing shall be permitted without tear off of existing roof coverings.

    Exception: A roof recover shall not be permitted where any of the following conditions occur:

    1. The existing roof or roof covering is water-soaked or has deteriorated to the point that the existing roof or roof covering is not adequate as a base for additional roofing.
    2. The existing roof covering is slate, clay, cement or asbestos-cement tile.
    3. The existing roof has two or more applications of any type of roof covering.

Frequently asked questions

What section sets roof fire classification requirements?

Fire classification is governed by §1505; it requires listed Class A/B/C assemblies tested to ASTM E108 or UL 790 and includes Table 1505.1 showing minimum classifications by construction type .

When does reroofing require full replacement versus a recover?

Section §1512 defines roof replacement (remove to the deck) and roof recover conditions; replacements are required when the existing roof is water‑soaked, deteriorated, has two or more existing roof coverings, or where other exceptions to recover apply .

Do rooftop PV or BIPV systems need to be fire‑classified?

Yes. Building‑integrated PV (BIPV) used as the roof covering must be listed and labeled for fire classification per §1505.1, and rooftop PV panel systems must comply with UL 2703 and the fire classification requirements in §1505.9 .

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