Copyright

Preface

Dedications

Acknowledgements

Chapter 1 Administration

Chapter 2 Definitions

Chapter 3 Use and Occupancy Classification

Chapter 4 Special Detailed Requirements Based on Use and Occupancy

Chapter 5 General Building Heights and Areas; Separation of Occupancies

Chapter 6 Types of Construction

Chapter 7 Fire and Smoke Protection Features

Chapter 8 Interior Finishes

Chapter 9 Fire Protection Systems

Chapter 10 Means of Egress

Chapter 11 Accessibility

Chapter 12 Interior Environment

Chapter 13 Energy Efficiency

Chapter 14 Exterior Walls

Chapter 15 Roof Assemblies and Rooftop Structures

Chapter 16 Structural Design

Chapter 17 Structural Tests and Special Inspections

Chapter 18 Soils and Foundations

Chapter 19 Concrete

Chapter 20 Aluminum

Chapter 21 Masonry

Chapter 22 Steel

Chapter 23 Wood

Chapter 24 Glass and Glazing

Chapter 25 Gypsum Board and Plaster

Chapter 26 Plastic

Chapter 27 Electrical

Chapter 28 Mechanical Systems

Chapter 29 Plumbing Systems

Chapter 30 Elevators and Conveying Systems

Chapter 31 Special Construction

Chapter 32 Encroachments Into the Public Right-Of-Way

Chapter 33 Safeguards During Construction or Demolition

Chapter 34 Reserved

Chapter 35 Referenced Standards

Appendix A Reserved

Appendix B Reserved

Appendix C Reserved

Appendix D Fire Districts

Appendix E Supplementary Accessibility Requirements

Appendix F Rodentproofing

Appendix G Flood-Resistant Construction

Appendix H Outdoor Signs

Appendix I Reserved

Appendix J Reserved

Appendix K Modified Industry Standards for Elevators and Conveying Systems

Appendix L Reserved

Appendix M Supplementary Requirements for One- And Two-Family Dwellings

Appendix N Assistive Listening Systems Performance Standards

Appendix O Reserved

Appendix P Type B+NYC Unit Toilet and Bathing Rooms Requirements

Appendix Q Modified National Standards for Automatic Sprinkler, Standpipe, Fire Pump and Fire Alarm Systems

Appendix R Acoustical Tile and Lay-In Panelceiling Suspension Systems

Appendix S Supplementary Figures for Luminous Egress Path Markings

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The provisions of this chapter shall govern the design, materials, construction and quality of roof assemblies, and rooftop structures.
The following terms shall, for the purposes of this chapter and as used elsewhere in this code, have the meanings shown herein.

AGGREGATE. In roofing, crushed stone, crushed slag or water-worn gravel used for surfacing for roof coverings.

BALLAST. In roofing, ballast comes in the form of large stones or paver systems or light-weight interlocking paver systems and is used to provide uplift resistance to components of the roof assembly systems that are not adhered or mechanically attached to the roof deck.

BUILT-UP ROOF COVERING. Two or more layers of felt cemented together and surfaced with a cap sheet, mineral aggregate, smooth coating or similar surfacing material.

BULKHEAD. An enclosed rooftop structure enclosing a shaft, stairway, tank or service equipment, or other space not designed or used for human occupancy.

CONTAINER GARDEN. A plant or plants maintained in a pot or planters that is at least 6 inches (152 mm) high and located on a roof, terrace, or other horizontal exterior area.

GREEN ROOF SYSTEM. A system constructed in-situ consisting of either a roof assembly and additional landscape material components, including growing media, engineered soils, filter fabric, integral drainage systems and roof surface to facilitate the growth of vegetation or a pre-vegetated tray or trays no more than 6 inches (152 mm) high and assembled on top of a roof covering.

INTERLAYMENT. A layer of felt or nonbituminous saturated felt not less than 18 inches (457 mm) wide, shingled between each course of a wood-shake roof covering.

MECHANICAL EQUIPMENT SCREEN. A partially enclosed rooftop structure used to aesthetically conceal heating, ventilating and air conditioning (HVAC) electrical or mechanical equipment from view.

METAL ROOF PANEL. An interlocking metal sheet having a minimum installed weather exposure of 3 square feet (.279 m2) per sheet.

METAL ROOF SHINGLE. An interlocking metal sheet having an installed weather exposure less than 3 square feet (.279 m2) per sheet.

MODIFIED BITUMEN ROOF COVERING. One or more layers of polymer-modified asphalt sheets. The sheet materials shall be fully adhered or mechanically attached to the substrate or held in place with an approved ballast layer.

PENTHOUSE. An enclosed rooftop structure which is designed or used for human occupancy.

POSITIVE ROOF DRAINAGE. The drainage condition in which consideration has been made for all loading deflections of the roof deck, including ponding instability, and additional slope has been provided to ensure drainage of the roof within 48 hours of precipitation.

REROOFING. The process of recovering or replacing an existing roof covering. See "Roof recover" and "Roof replacement."

ROOF ASSEMBLY. A system designed to provide weather protection and resistance to design loads. The system consists of a roof covering and roof deck or a single component serving as both the roof covering and the roof deck. A roof assembly includes the roof deck, substrate or thermal barrier, insulation, vapor retarder and roof covering. This definition of "Roof assembly" is limited in application to the provisions of Chapter 15.

ROOF COVERING. The covering applied to the roof deck for weather resistance, fire classification or appearance.

ROOF COVERING SYSTEM. See "Roof assembly."

ROOF DECK. The flat or sloped surface not including its supporting members or vertical supports.

ROOF RECOVER. The process of installing an additional roof covering over a prepared existing roof covering without removing the existing roof covering.

ROOF REPLACEMENT. The process of removing the existing roof covering, repairing any damaged substrate and installing a new roof covering.

ROOF VENTILATION. The natural or mechanical process of supplying conditioned or unconditioned air to, or removing such air from, attics, cathedral ceilings or other enclosed spaces over which a roof assembly is installed.

ROOFTOP STRUCTURE. An enclosed or unenclosed structure on or above the roof of any part of a building.

SINGLE-PLY MEMBRANE. A roofing membrane that is field applied using one layer of membrane material (either homogeneous or composite) rather than multiple layers.

UNDERLAYMENT. One or more layers of felt, sheathing paper, nonbituminous saturated felt or other approved material over which a steep-slope roof covering is applied.
Roof decks shall be covered with approved roof coverings secured to the building or structure in accordance with the provisions of this chapter. Roof coverings shall be designed and installed in accordance with this code and the approved manufacturer's instructions such that the roof covering shall serve to protect the building or structure.
Flashing shall be installed in such a manner so as to prevent moisture entering the wall and roof through joints in copings, through moisture-permeable materials and at intersections with parapet walls and other penetrations through the roof plane.
Flashing shall be installed at wall and roof intersections, at gutters, wherever there is a change in roof slope or direction and around roof openings. Where flashing is of metal, the metal shall be corrosion resistant with a thickness of not less than 0.019 inch (.483 mm) (No. 26 galvanized sheet).
Parapet walls shall be properly coped with noncombustible, weatherproof materials of a width no less than the thickness of the parapet wall.
Design and installation of roof drainage systems shall comply with this section and the New York City Plumbing Code.
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.
When scuppers are used for secondary (emergency overflow) roof drainage, the quantity, size, location and inlet elevation of the scuppers shall be sized to prevent the depth of ponding water from exceeding that for which the roof was designed as determined by Section 1503.4.1. Scuppers shall not have an opening dimension of less than 4 inches (102 mm). The flow through the primary system shall not be considered when locating and sizing scuppers.
Gutters and leaders placed on the outside of buildings shall be of noncombustible, corrosion-resistant material, or a minimum of Schedule 40 plastic pipe.
Vertical sections of exterior leaders made from galvanized steel, galvanized wrought iron, cast iron, brass, or similar heavy material shall be permitted only for the first 15 feet (4572 mm) of leader extending up from grade, provided that the leader is securely anchored with offset clamps to the face of the building at no fewer than two points along the vertical section of the leader. Horizontal sections of exterior gutter made from such heavy materials shall not be permitted higher than 15 feet (4572 mm) above grade.
Intake and exhaust vents shall be provided in accordance with Section 1203.2 and the manufacturer's installation instructions.
A cricket or saddle shall be installed on the ridge side of any chimney or penetration greater than 30 inches (762 mm) wide as measured perpendicular to the slope. Cricket or saddle coverings shall be sheet metal or of the same material as the roof covering.
Roof decks and roof coverings shall be designed for wind loads in accordance with Chapter 16 and Sections 1504.2, 1504.3 and 1504.4.
Asphalt shingles shall comply with Section 1507.2.
Wind loads on clay and concrete tile roof coverings shall be in accordance with Section 1609.
Roof coverings installed on roofs in accordance with Section 1507 that are mechanically attached or adhered to the roof deck shall be designed to resist the design wind load pressures for components and cladding in accordance with Section 1609.
Roof systems with built-up, modified bitumen, fully adhered or mechanically attached single-ply through fastened metal panel roof systems, and other types of membrane roof coverings shall also be tested in accordance with FM 4474, UL 580 or UL 1897.
Metal panel roof systems through fastened or standing seam shall be tested in accordance with UL 580 or ASTM E 1592.

Exception: Metal roofs constructed of cold-formed steel, where the roof deck acts as the roof covering and provides both weather protection and support for structural loads, shall be permitted to be designed and tested in accordance with the applicable referenced structural design standard in Section 2209.1.
Ballasted low-slope (roof slope < 2:12) single-ply roof system coverings installed in accordance with Sections 1507.12 and 1507.13 shall be designed in accordance with Section 1504.8 and ANSI/SPRI RP-4.
Low-slope membrane roof systems metal edge securement, except gutters, shall be designed and installed for wind loads in accordance with Chapter 16 and tested for resistance in accordance with ANSI/SPRI ES-1, except the basic wind speed shall be determined in accordance with Chapter 16.
Roof coverings installed on low-slope roofs (roof slope < 2:12) in accordance with Section 1507 shall demonstrate physical integrity over the working life of the roof based upon 2,000 hours of exposure to accelerated weathering tests conducted in accordance with ASTM G 152, ASTM G 155 or ASTM G 154. Those roof coverings that are subject to cyclical flexural response due to wind loads shall not demonstrate any significant loss of tensile strength for unreinforced membranes or breaking strength for reinforced membranes when tested as herein required.
Roof coverings installed on low-slope roofs (roof slope < 2:12) in accordance with Section 1507 shall resist impact damage based on the results of tests conducted in accordance with ASTM D 3746, ASTM D 4272, CGSB 37-GP-52M or the "Resistance to Foot Traffic Test" in Section 5.5 of FM 4470.
Aggregate used as surfacing for roof coverings and aggregate, gravel or stone used as ballast shall not be used on the roof of a building located in a hurricane-prone region as defined in Section 1609.2, or on any other building with a mean roof height exceeding that permitted by Table 1504.8 based on the exposure category and basic wind speed at the site.

TABLE 1504.8 MAXIMUM ALLOWABLE MEAN ROOF HEIGHT PERMITTED FOR BUILDINGS WITH AGGREGATE ON THE ROOF IN AREAS OUTSIDE A HURRICANE-PRONE REGIONd

BASIC WIND
SPEED FROM
SECTION 1609.3
(mph)b
MAXIMUM MEAN ROOF HEIGHT (ft)a, c
Exposure category
B C D
85 170 60 30
90 110 35 15
95 75 20 NP
100 55 15 NP
105 40 NP NP
110 30 NP NP
115 20 NP NP
120 15 NP NP
Greater than 120 NP NP NP

For SI: 1 foot = 304.8 mm; 1 mile per hour = 0.447 m/s.
a. Mean roof height as defined in ASCE 7.
b. For intermediate values of basic wind speed, the height associated with the next higher value of wind speed shall be used, or direct interpolation is permitted.
c. NP = gravel and stone not permitted for any roof height.
d. New York City is in a Hurricane-Prone Region pursuant to Section 1609.2.
Roof coverings on roofs or setbacks with slope equal to or less than two units vertical in 12 units horizontal (17 percent) shall have:

1. A minimum initial solar reflectance of 0.7 in accordance with ASTM C 1549 or ASTM E 1918, and a minimum thermal emittance of 0.75 as determined in accordance with ASTM C 1371 or ASTM E 408; or

2. A minimum SRI of 78 as determined in accordance with ASTM E 1980.

Exceptions:

1. Terraces on setbacks comprising less than 25 percent of the area of the largest floor plate in the building.

2. Any portion of a roof covered by a green roof system, including such a system with agricultural plantings, in compliance with Section 1507.16.

3. Any portion of a roof used as outdoor recreation space by the occupants of the building that is landscaped, covered by wood decking or covered with a walking surface or other protective surface, provided that such walking surface or protective surface has a minimum initial solar reflectance of 0.3 as determined in accordance with ASTM C 1549 or ASTM E 1918.

4. Ballasted roofs, provided that the ballast has a minimum initial solar reflectance of 0.2 as determined in accordance with ASTM C 1549 or ASTM E 1918.

5. Any portion of a roof that is under mechanical equipment, flush mounted solar panels lying directly on the roof surface, duckboarding, decking, platform, roof tank, cooling tower or any other rooftop structure or equipment exempted by rule by the commissioner.

6. Any roof or portion of a roof composed of glass, metal, clay or concrete tile or plastic/rubber intended to simulate clay or concrete tile, wood, or slate.

7. Any portion of a roof used by a school or daycare center as a playground for children.

8. Any roof, if the amount of rooftop space not subject to exceptions 1 through 7 is in the aggregate less than 100 square feet (9.3 m2).
Roof assemblies shall be divided into the classes defined below. Class A, B and C roof assemblies and roof coverings required to be listed by this section shall be tested in accordance with ASTM E 108 or UL 790. In addition, fire-retardant-treated wood roof coverings shall be tested in accordance with ASTM D 2898. The minimum roof coverings installed on buildings shall comply with Table 1505.1 based on the type of construction of the building.

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

TABLE 1505.1a,b MINIMUM ROOF COVERING CLASSIFICATION FOR TYPES OF CONSTRUCTION

IA IB IIA IIB IIIA IIIB IV VA VB
B B B B B B B B Cb

For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929 m2.
a. Unless otherwise required due to the location of the building within a fire district in accordance with Section D102.2.3 in Appendix D.
b. 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 in accordance with Section 1505.6.
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.
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.
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.
Roofs having a slope of more than 60 degrees (1.05 rad) to the horizontal shall be constructed of material having the same fire-resistance rating as required for an exterior nonbearing wall of the building of which it is a part. When the slope is 60 degrees (1.05 rad) or less to the horizontal, the sloping roof shall be constructed as required for the roof of the building. Where the back of a false mansard is exposed to the outdoors, the back shall be covered with noncombustible material or with roof covering as required for the roof of the building.
Fire-retardant-treated wood shakes and shingles shall be treated by impregnation with chemicals by the full-cell vacuum-pressure process, in accordance with AWPA C1. Each bundle shall be marked to identify the manufactured unit and the manufacturer, and shall also be labeled to identify the classification of the material in accordance with the testing required in Section 1505.1, the treating company and the quality control agency.
Special purpose wood shingle or wood shake roofing shall conform with the grading and application requirements of Section 1507.8 or Section 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.
Rooftop installed photovoltaic systems that are adhered or attached to the roof covering or photovoltaic modules/shingles installed as roof coverings shall be labeled to identify their fire classification in accordance with the testing required in Section 1505.1.
The requirements set forth in this section shall apply to the application of roof-covering materials specified herein. Roof coverings shall be applied in accordance with this chapter and the manufacturer's installation instructions. Installation of roof coverings shall comply with the applicable provisions of Section 1507.
Roofs and roof coverings shall be of materials that are compatible with each other and with the building or structure to which the materials are applied.
Roof-covering materials shall conform to the applicable standards listed in this chapter. In the absence of applicable standards or where materials are of questionable suitability, testing by an approved agency shall be required by the commissioner to determine the character, quality and limitations of application of the materials.
Roof-covering materials shall be delivered in packages bearing the manufacturer's identifying marks and approved testing agency labels required in accordance with Section 1505. Bulk shipments of materials shall be accompanied with the same information issued in the form of a certificate or on a bill of lading by the manufacturer.
Roof coverings shall be applied in accordance with the applicable provisions of this section and the manufacturer's installation instructions.
The installation of asphalt shingles shall comply with the provisions of this section.
Asphalt shingles shall be fastened to solidly sheathed decks.
Asphalt shingles shall only be used on roof slopes of two units vertical in 12 units horizontal (17-percent slope) or greater. For roof slopes from two units vertical in 12 units horizontal (17-percent slope) up to four units vertical in 12 units horizontal (33-percent slope), double underlayment application is required in accordance with Section 1507.2.8.
Unless otherwise noted, required underlayment shall conform to ASTM D 226, Type I, ASTM D 4869, Type I, or ASTM D 6757.
Self-adhering polymer modified bitumen sheet shall comply with ASTM D 1970.
Asphalt shingles shall comply with ASTM D 225 or ASTM D 3462.
Fasteners for asphalt shingles shall be galvanized, stainless steel, aluminum or copper roofing nails, minimum 12 gage (0.105 inches (2.67 mm)) shank with a minimum 3/8 inch-diameter (9.5 mm) head, of a length to penetrate through the roofing materials and a minimum of 3/4 inch (19.1 mm) into the roof sheathing. Where the roof sheathing is less than 3/4 inch (19.1 mm) thick, the nails shall penetrate through the sheathing. Fasteners shall comply with ASTM F 1667.
Asphalt shingles shall have the minimum number of fasteners required by the manufacturer, but not less than four fasteners per strip shingle or two fasteners per individual shingle. Where the roof slope exceeds 21 units vertical in 12 units horizontal (21:12), shingles shall be installed as required by the manufacturer.
Asphalt shingles shall be tested in accordance with ASTM D 7158. Asphalt shingles shall meet the classification requirements of Table 1507.2.7.1(1) for the maximum basic wind speed per Section 1609. Asphalt shingle packaging shall bear a label to indicate compliance with ASTM D 7158 and the required classification in Table 1507.2.7.1(1).

Exception: Asphalt shingles not included in the scope of ASTM D 7158 shall be tested and labeled to indicate compliance with ASTM D 3161 and the required classification in Table 1507.2.7.1(2).

TABLE 1507.2.7.1(1) CLASSIFICATION OF ASPHALT ROOF PER ASTM D 7158a

MAXIMUM BASIC WIND SPEED
FROM SECTION 1609
CLASSIFICATION
REQUIREMENT
85 D, G, or H
90 D, G, or H
100 G or H
110 G or H
120 G or H
130 H
140 H
150 H

a. The standard calculations contained in ASTM D 7158 assume exposure category B or C and building height of 60 feet (18 288 mm) or less. Additional calculations are required for conditions outside of these assumptions.


TABLE 1507.2.7.1(2) CLASSIFICATION OF ASPHALT SHINGLES PER ASTM D 3161

MAXIMUM BASIC WIND SPEED
FROM SECTION 1609
CLASSIFICATION
REQUIREMENT
85 A, D or F
90 A, D or F
100 A, D or F
110 F
120 F
130 F
140 F
150 F
For roof slopes from two units vertical in 12 units horizontal (17-percent slope), up to four units vertical in 12 units horizontal (33-percent slope), underlayment shall be two layers applied in the following manner. Apply a minimum 19-inch-wide (483 mm) strip of underlayment felt parallel with and starting at the eaves, fastened sufficiently to hold in place. Starting at the eave, apply 36-inch-wide (914 mm) sheets of underlayment overlapping successive sheets 19 inches (483 mm) and fastened sufficiently to hold in place. Distortions in the underlayment shall not interfere with the ability of the shingles to seal. For roof slopes of four units vertical in 12 units horizontal (33-percent slope) or greater, underlayment shall be one layer applied in the following manner. Underlayment shall be applied shingle fashion, parallel to and starting from the eave and lapped 2 inches (51 mm), fastened only as necessary to hold in place. Distortions in the underlayment shall not interfere with the ability of the shingles to seal.
An ice barrier that consists of at least two layers of underlayment cemented together or of a self-adhering polymer modified bitumen sheet shall be used in lieu of normal underlayment and extend from the lowest edges of all roof surfaces to a point at least 24 inches (610 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.
Flashing for asphalt shingles shall comply with this section. Flashing shall be applied in accordance with this section and the asphalt shingle manufacturer's printed instructions.
Base and cap flashing shall be installed in accordance with the manufacturer's instructions. Base flashing shall be of either corrosion-resistant metal of minimum nominal 0.019-inch (0.483 mm) thickness or mineral-surfaced roll roofing weighing a minimum of 77 pounds per 100 square feet (3.76 kg/m2). Cap flashing shall be corrosion-resistant metal of minimum nominal 0.019-inch (0.483 mm) thickness.
Valley linings shall be installed in accordance with the manufacturer's instructions before applying shingles. Valley linings of the following types shall be permitted:

1. For open valleys (valley lining exposed) lined with metal, the valley lining shall be at least 24 inches (610 mm) wide and of any of the corrosion-resistant metals in Table 1507.2.9.2.

2. For open valleys, valley lining of two plies of mineral-surfaced roll roofing complying with ASTM D 3909 or ASTM D 6380 shall be permitted. The bottom layer shall be 18 inches (457 mm) and the top layer a minimum of 36 inches (914 mm) wide.

3. For closed valleys (valleys covered with shingles), valley lining of one ply of smooth roll roofing complying with ASTM D 6380 and at least 36 inches (914 mm) wide or types as described in Item 1 or 2 above shall be permitted. Self-adhering polymer modified bitumen underlayment complying with ASTM D 1970 shall be permitted in lieu of the lining material.

TABLE 1507.2.9.2 VALLEY LINING MATERIAL

MATERIAL MINIMUM
THICKNESS
GAGE WEIGHT
Aluminum 0.024 in.
Cold-rolled copper 0.0216 in. ASTM B 370,
16 oz. per sq. ft.
Copper 16 oz.
Galvanized steel 0.0179 in. 26 (zinc-
coated
G90)
High-yield copper 0.0162 in. ASTM B 370,
12 oz. per sq. ft.
Lead 2.5 pounds
Lead-coated copper 0.0216 in. ASTM B 101,
16 oz. per sq. ft.
Lead-coated high-
yield copper
0.0162 ASTM B 101,
12 oz. per sq. ft.
Painted terne 20 pounds
Stainless steel 28
Zinc alloy 0.027 in.

For SI: 1 inch = 25.4 mm, 1 pound = 0.454 kg, 1 ounce = 28.35 g.
Provide drip edge at eaves and gables of shingle roofs. Overlap to be a minimum of 2 inches (51 mm). Eave drip edges shall extend 1/4 inch (6.4 mm) below sheathing and extend back on the roof a minimum of 2 inches (51 mm). Drip edge shall be mechanically fastened a maximum of 12 inches (305 mm) o.c.
The installation of clay and concrete tile shall comply with the provisions of this section.
Concrete and clay tile shall be installed only over solid sheathing or spaced structural sheathing boards.
Clay and concrete roof tile shall be installed on roof slopes of 21/2 units vertical in 12 units horizontal (21-percent slope) or greater. For roof slopes from 21/2 units vertical in 12 units horizontal (21-percent slope) to four units vertical in 12 units horizontal (33-percent slope), double underlayment application is required in accordance with Section 1507.3.3.
Unless otherwise noted, required underlayment shall conform to: ASTM D 226, Type II; ASTM D 2626 or ASTM D 6380, Class M mineral-surfaced roll roofing.
For roof slopes from 21/2 units vertical in 12 units horizontal (21-percent slope), up to four units vertical in 12 units horizontal (33-percent slope), underlayment shall be a minimum of two layers applied as follows:

1. Starting at the eave, a 19-inch (483 mm) strip of underlayment shall be applied parallel with the eave and fastened sufficiently in place.

2. Starting at the eave, 36-inch-wide (914 mm) strips of underlayment felt shall be applied overlapping successive sheets 19 inches (483 mm) and fastened sufficiently in place.
For roof slopes of four units vertical in 12 units horizontal (33-percent slope) or greater, underlayment shall be a minimum of one layer of underlayment felt applied shingle fashion, parallel to, and starting from the eaves and lapped 2 inches (51 mm), fastened only as necessary to hold in place.
Clay roof tile shall comply with ASTM C 1167.
Concrete roof tile shall comply with ASTM C 1492.
Tile fasteners shall be corrosion resistant and not less than 11 gage, 5/16-inch (8.0 mm) head, and of sufficient length to penetrate the deck a minimum of 3/4 inch (19.1 mm) or through the thickness of the deck, whichever is less. Attaching wire for clay or concrete tile shall not be smaller than 0.083 inch (2.1 mm). Perimeter fastening areas include three tile courses but not less than 36 inches (914 mm) from either side of hips or ridges and edges of eaves and gable rakes.
Clay and concrete roof tiles shall be fastened in accordance with Table 1507.3.7.

TABLE 1507.3.7 CLAY AND CONCRETE TILE ATTACHMENTa, b, c

GENERAL ‒ CLAY OR CONCRETE ROOF TILE
Maximum basic
wind speed
(mph)
Mean roof
height
(feet)
Roof slope up to < 3:12 Roof slope 3:12 and over
85 0-60 One fastener per tile. Flat tile
without vertical laps, two fasteners
per tile.
Two fasteners per tile. Only one fastener on slopes of 7:12 and less for
tiles with installed weight exceeding 7.5 lbs./sq. ft. having a width no
greater than 16 inches.
100 0-40
100 > 40-60 The head of all tiles shall be nailed. The nose of all eave tiles shall be fastened with approved clips. All rake
tiles shall be nailed with two nails. The nose of all ridge, hip and rake tiles shall be set in a bead of roofer's
mastic.
110 0-60 The fastening system shall resist the wind forces in Section 1609.7.3.
120 0-60 The fastening system shall resist the wind forces in Section 1609.7.3.
130 0-60 The fastening system shall resist the wind forces in Section 1609.7.3.
All > 60 The fastening system shall resist the wind forces in Section 1609.7.3.
INTERLOCKING CLAY OR CONCRETE ROOF TILE WITH PROJECTING ANCHOR LUGSd, e
(Installations on spaced/solid sheathing with battens or spaced sheathing)
Maximum basic
wind speed
(mph)
Mean roof
height
(feet)
Roof slope up to < 5:12 Roof slope 5:12 < 12:12 Roof slope 12:12 and over
85 0-60 Fasteners are not required. Tiles
with installed weight less than 9
lbs./sq. ft. require a minimum of
one fastener per tile.
One fastener per tile every other
row. All perimeter tiles require one
fastener. Tiles with installed
weight less than 9 lbs./sq. ft.
require a minimum of one fastener
per tile.
One fastener required for every
tile. Tiles with installed weight
less than 9 lbs./sq. ft. require a
minimum of one fastener per tile.
100 0-40
100 > 40-60 The head of all tiles shall be nailed. The nose of all eave tiles shall be fastened with approved clips. All rake
tiles shall be nailed with two nails The nose of all ridge, hip and rake tiles shall be set in a bead of roofers's
mastic.
110 0-60 The fastening system shall resist the wind forces in Section 1609.7.3.
120 0-60 The fastening system shall resist the wind forces in Section 1609.7.3.
130 0-60 The fastening system shall resist the wind forces in Section 1609.7.3.
All > 60 The fastening system shall resist the wind forces in Section 1609.7.3.
INTERLOCKING CLAY OR CONCRETE ROOF TILE WITH PROJECTING ANCHOR LUGS
(Installations on solid sheathing without battens)
Maximum basic
wind speed
(mph)
Mean roof
height
(feet)
All roof slopes
85 0-60 One fastener per tile.
100 0-40 One fastener per tile.
100 > 40-60 The head of all tiles shall be nailed. The nose of all eave tiles shall be fastened with approved clips. All rake
tiles shall be nailed with two nails The nose of all ridge, hip and rake tiles shall be set in a bead of roofers's
mastic.
110 0-60 The fastening system shall resist the wind forces in Section 1609.7.3.
120 0-60 The fastening system shall resist the wind forces in Section 1609.7.3.
130 0-60 The fastening system shall resist the wind forces in Section 1609.7.3.
All > 60 The fastening system shall resist the wind forces in Section 1609.7.3.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s, 1 pound per square foot = 4.882 kg/m2.
a. Minimum fastener size. Corrosion-resistant nails not less than No. 11 gage with 5/16-inch head. Fasteners shall be long enough to penetrate into the sheathing 3/4 inch or through the thickness of the sheathing, whichever is less. Attaching wire for clay and concrete tile shall not be smaller than 0.083 inch.
b. Snow areas. A minimum of two fasteners per tile are required or battens and one fastener.
c. Roof slopes greater than 24:12. The nose of all tiles shall be securely fastened.
d. Horizontal battens. Battens shall be not less than 1inch by 2 inch nominal. Provisions shall be made for drainage by a minimum of 1/8-inch riser at each nail or by 4-foot-long battens with at least a 1/2-inch separation between battens. Horizontal battens are required for slopes over 7:12.
e. Perimeter fastening areas include three tile courses but not less than 36 inches from either side of hips or ridges and edges of eaves and gable rakes.
Tile shall be applied according to the manufacturer's installation instructions, based on the following:

1. Climatic conditions.

2. Roof slope.

3. Underlayment system.

4. Type of tile being installed.
At the juncture of the roof vertical surfaces, flashing and counterflashing shall be provided in accordance with the manufacturer's installation instructions, and where of metal, shall not be less than 0.019-inch (0.48 mm) (No. 26 galvanized sheet gage) corrosion-resistant metal. The valley flashing shall extend at least 11 inches (279 mm) from the centerline each way and have a splash diverter rib not less than 1 inch (25 mm) high at the flow line formed as part of the flashing. Sections of flashing shall have an end lap of not less than 4 inches (102 mm). For roof slopes of three units vertical in 12 units horizontal (25-percent slope) and over, the valley flashing shall have a 36-inch-wide (914 mm) underlayment of either one layer of Type I underlayment running the full length of the valley, or a self-adhering polymer-modified bitumen sheet complying with ASTM D 1970, in addition to other required underlayment. For slopes under seven units vertical in 12 units horizontal (58-percent slope), the metal valley flashing underlayment shall be solid cemented to the roofing underlayment or a self-adhering polymer modified bitumen sheet shall be installed.
The installation of metal roof panels shall comply with the provisions of this section.
Metal roof panel roof coverings shall be applied to a solid or closely fitted deck, except where the roof covering is specifically designed to be applied to spaced supports.
The minimum slope for metal roof panels shall comply with the following:

1. The minimum slope for lapped, nonsoldered seam metal roofs without applied lap sealant shall be three units vertical in 12 units horizontal (25-percent slope).

2. The minimum slope for lapped, nonsoldered seam metal roofs with applied lap sealant shall be one-half unit vertical in 12 units horizontal (4-percent slope). Lap sealants shall be applied in accordance with the approved manufacturer's installation instructions.

3. The minimum slope for standing seam of roof systems shall be one-quarter unit vertical in 12 units horizontal (2-percent slope).
Metal-sheet roof covering systems that incorporate supporting structural members shall be designed in accordance with Chapter 22. Metal-sheet roof coverings installed over structural decking shall comply with Table 1507.4.3(1). The materials used for metal-sheet roof coverings shall be naturally corrosion resistant or provided with corrosion resistance in accordance with the standards and minimum thicknesses shown in Table 1507.4.3(2).

TABLE 1507.4.3(1) METAL ROOF COVERINGS

ROOF COVERING TYPE STANDARD APPLICATION
RATE/THICKNESS
Aluminum ASTM B 209, 0.024 inch minimum thickness
for roll-formed panels and 0.019 inch minimum thickness for press-formed shingles.
Aluminum-zinc
alloy coated steel
ASTM A 792 AZ 50
Cold-rolled copper ASTM B 370 minimum 16 oz./sq. ft. and 12
oz. /sq. ft. high yield copper for metal-sheet
roof covering systems: 12 oz./sq. ft. for preformed metal shingle systems.
Copper 16 oz./sq. ft. for metal-sheet roof-covering
systems; 12 oz./sq. ft. for preformed metal
shingle systems.
Galvanized steel ASTM A 653 G-90 zinc-coated a
Hard lead 2 lbs. /sq. ft.
Lead-coated copper ASTM B 101
Prepainted steel ASTM A 755
Soft lead 3 lbs./sq. ft.
Stainless steel ASTM A 240, 300 Series Alloys
Steel ASTM A 924
Terne and terne-
coated stainless
Terne coating of 40 lbs. per double base box,
field painted where applicable in accordance
with manufacturer's installation instructions.
Zinc 0.027 inch minimum thickness; 99.995% elec-
trolytic high grade zinc with alloy additives of
copper (0.08% - 0.20%), titanium (0.07% -
0.12%) and aluminum (0.015%).

For SI: 1 ounce per square foot = 0.0026 kg/m2,
1 pound per square foot = 4.882 kg/m2, 1 inch = 25.4 mm,
1 pound = 0.454 kg.
a. For Group U buildings, the minimum coating thickness for ASTM A 653 galvanized steel roofing shall be G-60.


TABLE 1507.4.3(2) MINIMUM CORROSION RESISTANCE

55% Aluminum-zinc alloy coated steel ASTM A 792 AZ 50
5% Aluminum alloy-coated steel ASTM A 875 GF60
Aluminum-coated steel ASTM A 463 T2 65
Galvanized steel ASTM A 653 G-90
Prepainted steel ASTM A 755a

a. Paint systems in accordance with ASTM A 755 shall be applied over steel products with corrosion resistant coatings complying with ASTM A 792, ASTM A 875, ASTM A 463 or ASTM A 653.
Metal roof panels shall be secured to the supports in accordance with the approved manufacturers' fasteners. In the absence of manufacturer recommendations, the following fasteners shall be used:

1. Galvanized fasteners shall be used for steel roofs.

2. Copper, brass, bronze, copper alloy or 300 series stainless-steel fasteners shall be used for copper roofs.

3. Stainless-steel fasteners are acceptable for all types of metal roofs.
The installation of metal roof shingles shall comply with the provisions of this section.
Metal roof shingles shall be applied to a solid or closely fitted deck, except where the roof covering is specifically designed to be applied to spaced sheathing.
Metal roof shingles shall not be installed on roof slopes below three units vertical in 12 units horizontal (25-percent slope).
Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869.
An ice barrier that consists of at least two layers of underlayment cemented together or of a self-adhering polymer-modified bitumen sheet, shall be used in lieu of normal underlayment and extend from the lowest edges of all roof surfaces to a point at least 24 inches (610 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.
Metal roof shingle roof coverings shall comply with Table 1507.4.3(1). The materials used for metal-roof shingle roof coverings shall be naturally corrosion resistant or provided with corrosion resistance in accordance with the standards and minimum thicknesses specified in the standards listed in Table 1507.4.3(2).
Metal roof shingles shall be secured to the roof in accordance with the approved manufacturer's installation instructions.
Roof valley flashing shall be of corrosion-resistant metal of the same material as the roof covering or shall comply with the standards in Table 1507.4.3(1). The valley flashing shall extend at least 8 inches (203 mm) from the centerline each way and shall have a splash diverter rib not less than 3/4 inch (19.1 mm) high at the flow line formed as part of the flashing. Sections of flashing shall have an end lap of not less than 4 inches (102 mm). The metal valley flashing shall have a 36-inch-wide (914 mm) underlayment directly under it consisting of either one layer of underlayment running the full length of the valley or a self-adhering polymer-modified bitumen sheet complying with ASTM D 1970, in addition to underlayment required for metal roof shingles. For slopes under seven units vertical in 12 units horizontal (58-percent slope), the metal valley flashing shall be solid cemented to the roofing underlayment or a self-adhering polymer bitumen sheet shall be installed.
The installation of mineral-surfaced roll roofing shall comply with this section.
Mineral-surfaced roll roofing shall be fastened to solidly sheathed roofs.
Mineral-surfaced roll roofing shall not be applied on roof slopes below one unit vertical in 12 units horizontal (8-percent slope).
Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869.
An ice barrier that consists of at least two layers of underlayment cemented together or of a self-adhering polymer-modified bitumen sheet, shall be used in lieu of normal underlayment and extend from the lowest edges of all roof surfaces to a point at least 24 inches (610 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.
Mineral-surfaced roll roofing shall conform to ASTM D 3909 or ASTM D 6380.
The installation of slate shingles shall comply with the provisions of this section.
Slate shingles shall be fastened to solidly sheathed roofs.
Slate shingles shall only be used on slopes of four units vertical in 12 units horizontal (4:12) or greater.
Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869.
An ice barrier that consists of at least two layers of underlayment cemented together or of a self-adhering polymer-modified bitumen sheet, shall extend from the lowest edges of all roof surfaces to a point at least 24 inches (610 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.
Slate shingles shall comply with ASTM C 406.
Minimum headlap for slate shingles shall be in accordance with Table 1507.7.6. Slate shingles shall be secured to the roof with two fasteners per slate.

TABLE 1507.7.6 SLATE SHINGLE HEADLAP

SLOPE HEADLAP
(inches)
4:12 < slope < 8:12 4
8:12 < slope < 20:12 3
slope ≥ 20:12 2

For SI: 1 inch = 25.4 mm.
Flashing and counterflashing shall be made with sheet metal. Valley flashing shall be a minimum of 15 inches (381 mm) wide. Valley and flashing metal shall be a minimum uncoated thickness of 0.0179-inch (0.455 mm) zinc-coated G90. Chimneys, stucco or brick walls shall have a minimum of two plies of felt for a cap flashing consisting of a 4-inch-wide (102 mm) strip of felt set in plastic cement and extending 1 inch (25 mm) above the first felt and a top coating of plastic cement. The felt shall extend over the base flashing 2 inches (51 mm).
The installation of wood shingles shall comply with the provisions of this section and Table 1507.8.

TABLE 1507.8 WOOD SHINGLE AND SHAKE INSTALLATION

ROOF ITEM WOOD SHINGLES WOOD SHAKES
1. Roof slope Wood shingles shall be installed on slopes of
three units vertical in 12 units horizontal (3:12) or greater.
Wood shakes shall be installed on slopes of four units
vertical in 12 units horizontal (4:12) or greater.
2. Deck requirement
Temperate climate Shingles shall be applied to roofs with solid or spaced
sheathing. Where spaced sheathing is used, sheathing
boards shall not be less than 1" × 4" nominal dimen-
sions and shall be spaced on center equal to the
weather exposure to coincide with the placement of
fasteners.
Shakes shall be applied to roofs with solid or spaced
sheathing. Where spaced sheathing is used, sheathing
boards shall not be less than 1" × 4" nominal dimen-
sions and shall be spaced on center equal to the
weather exposure to coincide with the placement of
fasteners. When 1" × 4" spaced sheathing is installed
at 10 inches, boards must be installed between the
sheathing boards.
Ice forming along the
eaves causing a backup
of water.
Solid sheathing required. Solid sheathing is required.
3. Interlayment No requirements. Interlayment shall comply with ASTM D 226, Type 1.
4. Underlayment
Temperate climate Underlayment shall comply with ASTM D 226, Type
1.
Underlayment shall comply with ASTM D 226, Type
1.
Ice forming along the
eaves causing a backup
of water.
An ice barrier that consists of at least two layers of
underlayment cemented together or of a self-adhering
polymer-modified bitumen sheet shall extend from
the eave's edge to a point at least 24 inches inside the
exterior wall line of the building.
An ice barrier that consists of at least two layers of
underlayment cemented together or of a self-adhering
polymer-modified bitumen sheet shall extend from the
lowest eave's edge of all roof surfaces to a point at
least 24 inches inside the exterior wall line of the
building.
5. Application
Attachment Fasteners for wood shingles shall be hot-dipped gal-
vanized or Type 304 (Type 316 for coastal areas)
stainless steel with a minimum penetration of 0.75
inch into the sheathing. For sheathing less than 0.5
inch thick, the fasteners shall extend through the
sheathing.
Fasteners for wood shakes shall be hot-dipped galva-
nized or Type 304 (Type 316 for coastal areas) with a
minimum penetration of 0.75 inch into the sheath-
ing. For sheathing less than 0.5 inch thick, the fas-
teners shall extend through the sheathing.
No. of fasteners Two per shingle. Two per shake.
Exposure Weather exposures shall not exceed those set forth in
Table 1507.8.7.
Weather exposures shall not exceed those set forth in
Table 1507.9.8.
Method Shingles shall be laid with a side lap of not less than
1.5 inches between joints in courses, and no two
joints in any three adjacent courses shall be in direct
alignment. Spacing between shingles shall be 0.25
to 0.375 inch.
Shakes shall be laid with a side lap of not less than 1.5
inches between joints in adjacent courses. Spacing
between shakes shall not be less than 0.375 inch or
more than 0.625 inch for shakes and tapersawn shakes
of naturally durable wood and shall be 0.25 to 0.375
inch for preservative taper sawn shakes.
Flashing In accordance with Section 1507.8.8. In accordance with Section 1507.9.9.

For SI: 1 inch = 25.4 mm, °C = [(°F) ‒ 32]/1.8.
Wood shingles shall be installed on solid or spaced sheathing. Where spaced sheathing is used, sheathing boards shall not be less than 1-inch by 4-inch (25 mm by 102 mm) nominal dimensions and shall be spaced on centers equal to the weather exposure to coincide with the placement of fasteners.
Solid sheathing is required.
Wood shingles shall be installed on slopes of three units vertical in 12 units horizontal (25-percent slope) or greater.
Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869.
An ice barrier that consists of at least two layers of underlayment cemented together or of a self-adhering polymer-modified bitumen sheet shall be used in lieu of normal underlayment and extend from the lowest edges of all roof surfaces to a point at least 24 inches (610 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.
Wood shingles shall be of naturally durable wood and comply with the requirements of Table 1507.8.5.

TABLE 1507.8.5 WOOD SHINGLE MATERIAL REQUIREMENTS

MATERIAL APPLICABLE
MINIMUM GRADES
GRADING RULES
Wood shingles of naturally
durable wood
1, 2 or 3 CSSB

CSSB = Cedar Shake and Shingle Bureau
Fasteners for wood shingles shall be corrosion resistant with a minimum penetration of 3/4 inch (19.1 mm) into the sheathing. For sheathing less than 1/2 inch (12.7 mm) in thickness, the fasteners shall extend through the sheathing. Each shingle shall be attached with a minimum of two fasteners.
Wood shingles shall be laid with a side lap not less than 11/2 inches (38 mm) between joints in adjacent courses, and not be in direct alignment in alternate courses. Spacing between shingles shall be 1/4 to 3/8 inches (6.4 to 9.5 mm). Weather exposure for wood shingles shall not exceed that set in Table 1507.8.7.

TABLE 1507.8.7 WOOD SHINGLE WEATHER EXPOSURE AND ROOF SLOPE

ROOFING
MATERIAL
LENGTH
(inches)
GRADE EXPOSURE (inches)
3:12 pitch
to < 4:12
4:12 pitch
or steeper
Shingles of
naturally
durable wood
16 No. 1 3.75 5
No. 2 3.5 4
No. 3 3 3.5
18 No. 1 4.25 5.5
No. 2 4 4.5
No. 3 3.5 4
24 No. 1 5.75 7.5
No. 2 5.5 6.5
No. 3 5 5.5

For SI: 1 inch = 25.4 mm.
At the juncture of the roof and vertical surfaces, flashing and counterflashing shall be provided in accordance with the manufacturer's installation instructions, and where of metal, shall not be less than 0.019-inch (0.48 mm) (No. 26 galvanized sheet gage) corrosion-resistant metal. The valley flashing shall extend at least 11 inches (279 mm) from the centerline each way and have a splash diverter rib not less than 1 inch (25 mm) high at the flow line formed as part of the flashing. Sections of flashing shall have an end lap of not less than 4 inches (102 mm). For roof slopes of three units vertical in 12 units horizontal (25-percent slope) and over, the valley flashing shall have a 36-inch-wide (914 mm) underlayment of either one layer of Type I underlayment running the full length of the valley or a self-adhering polymer-modified bitumen sheet complying with ASTM D 1970, in addition to other required underlayment. For slopes under seven units vertical in 12 units horizontal (58-percent slope), the metal valley flashing underlayment shall be solid cemented to the roofing underlayment or a self-adhering polymer modified bitumen sheet shall be installed.
The installation of wood shakes shall comply with the provisions of this section and Table 1507.8.
Wood shakes shall only be used on solid or spaced sheathing. Where spaced sheathing is used, sheathing boards shall not be less than 1-inch by 4-inch (25 mm by 102 mm) nominal dimensions and shall be spaced on centers equal to the weather exposure to coincide with the placement of fasteners. Where 1-inch by 4-inch (25 mm by 102 mm) spaced sheathing is installed at 10 inches (254 mm) o.c., additional 1-inch by 4-inch (25 mm by 102 mm) boards shall be installed between the sheathing boards.
Solid sheathing is required in areas where the average daily temperature in January is 25°F (-4°C) or less or where there is a possibility of ice forming along the eaves causing a backup of water.
Wood shakes shall only be used on slopes of four units vertical in 12 units horizontal (33-percent slope) or greater.
Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869.
An ice barrier that consists of at least two layers of underlayment cemented together or of a self-adhering polymer-modified bitumen sheet shall be used in lieu of normal underlayment and extend from the lowest edges of all roof surfaces to a point at least 24 inches (610 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.
Interlayment shall comply with ASTM D 226, Type I.
Wood shakes shall comply with the requirements of Table 1507.9.6.

TABLE 1507.9.6 WOOD SHAKE MATERIAL REQUIREMENTS

MATERIAL MINIMUM
GRADES
APPLICABLE
GRADING
RULES
Wood shakes of naturally durable wood 1 CSSB
Taper sawn shakes of naturally durable
wood
1 or 2 CSSB
Preservative-treated shakes and shin-
gles of naturally durable wood
1 CSSB
Fire-retardant-treated shakes and shin-
gles of naturally durable wood
1 CSSB
Preservative-treated taper sawn shakes
of Southern pine treated in accordance
with AWPA U1 (Commodity Specifica-
tion A, Use Category 3B and Section
5.6)
1 or 2 TFS

CSSB = Cedar Shake and Shingle Bureau.
TFS = Forest Products Laboratory of the Texas Forest Services.
Fasteners for wood shakes shall be corrosion resistant with a minimum penetration of 3/4 inch (19.1 mm) into the sheathing. For sheathing less than 1/2 inch (12.7 mm) in thickness, the fasteners shall extend through the sheathing. Each shake shall be attached with a minimum of two fasteners.
Wood shakes shall be laid with a side lap not less than 11/2 inches (38 mm) between joints in adjacent courses. Spacing between shakes in the same course shall be 3/8 to 5/8 inches (9.5 to 15.9 mm) for shakes and taper sawn shakes of naturally durable wood and shall be 1/4 to 3/8 inch (6.4 to 9.5 mm) for preservative taper sawn shakes. Weather exposure for wood shakes shall not exceed those set in Table 1507.9.8.

TABLE 1507.9.8 WOOD SHAKE WEATHER EXPOSURE AND ROOF SLOPE

ROOFING MATERIAL LENGTH
(inches)
GRADE EXPOSURE
(inches)
4:12 PITCH
OR STEEPER
Shakes of naturally
durable wood
18 No. 1 7.5
24 No. 1 10a
Preservative-treated taper
sawn shakes of Southern
yellow pine
18 No. 1 7.5
24 No. 1 10
18 No. 2 5.5
24 No. 2 7.5
Taper sawn shakes of
naturally durable wood
18 No. 1 7.5
24 No. 1 10
18 No. 2 5.5
24 No. 2 7.5

For SI: 1 inch = 25.4 mm.
a. For 24-inch by 0.375-inch handsplit shakes, the maximum exposure is 7.5 inches.
At the juncture of the roof and vertical surfaces, flashing and counterflashing shall be provided in accordance with the manufacturer's installation instructions, and where of metal, shall not be less than 0.019-inch (0.48 mm) (No. 26 galvanized sheet gage) corrosion-resistant metal. The valley flashing shall extend at least 11 inches (279 mm) from the centerline each way and have a splash diverter rib not less than 1 inch (25 mm) high at the flow line formed as part of the flashing. Sections of flashing shall have an end lap of not less than 4 inches (102 mm). For roof slopes of three units vertical in 12 units horizontal (25-percent slope) and over, the valley flashing shall have a 36-inch-wide (914 mm) underlayment of either one layer of Type I underlayment running the full length of the valley or a self-adhering polymer-modified bitumen sheet complying with ASTM D 1970, in addition to other required underlayment. For slopes under seven units vertical in 12 units horizontal (58-percent slope), the metal valley flashing underlayment shall be solidly cemented to the roofing underlayment or a self-adhering polymer-modified bitumen sheet shall be installed.
The installation of built-up roofs shall comply with the provisions of this section.
Built-up roofs shall have a slope designed and built to provide positive roof drainage.
Built-up roof covering materials shall comply with the standards in Table 1507.10.2.

TABLE 1507.10.2 BUILT-UP ROOFING MATERIAL STANDARDS

MATERIAL STANDARD STANDARD
Acrylic coatings used in roofing ASTM D 6083
Aggregate surfacing ASTM D 1863
Asphalt adhesive used in roofing ASTM D 3747
Asphalt cements used in roofing ASTM D 3019; D 2822;
D 4586
Asphalt-coated glass fiber base sheet ASTM D 4601
Asphalt coatings used in roofing ASTM D1227; D 2823;
D 4479
Asphalt glass felt ASTM D 2178
Asphalt primer used in roofing ASTM D 41
Asphalt-saturated and asphalt-coated
organic felt base sheet
ASTM D 2626
Asphalt-saturated organic felt
(perforated)
ASTM D 226
Asphalt used in roofing ASTM D 312
Coal-tar cements used in roofing ASTM D 4022; D 5643
Coal-tar saturated organic felt ASTM D 227
Coal-tar pitch used in roofing ASTM D 450; Type I or II
Coal-tar primer used in roofing,
damproofing and waterproofing
ASTM D 43
Glass mat, coal tar ASTM D 4990
Glass mat, venting type ASTM D 4897
Mineral-surfaced inorganic cap sheet ASTM D 3909
Thermoplastic fabrics used in roofing ASTM D 5665, D 5726
The installation of modified bitumen roofing shall comply with the provisions of this section.
Modified bitumen membrane roofs shall have a slope designed and built to provide positive roof drainage.
Modified bitumen roof coverings shall comply with CGSB 37-GP-56M, ASTM D 6162, ASTM D 6163, ASTM D 6164, ASTM D 6222, ASTM D 6223, ASTM D 6298 and ASTM D 6509.
The installation of thermoset single-ply roofing shall comply with the provisions of this section.
Thermoset single-ply membrane roofs shall have a slope designed and built to provide positive roof drainage.
Thermoset single-ply roof coverings shall comply with ASTM D 4637, ASTM D 5019 or CGSB 37-GP-52M.
Ballasted thermoset low-slope roofs (roof slope < 2:12) shall be installed in accordance with this section and Section 1504.4. Stone used as ballast shall comply with ASTM D 448.
The installation of thermoplastic single-ply roofing shall comply with the provisions of this section.
Thermoplastic single-ply membrane roofs shall have a slope designed and built to provide positive roof drainage.
Thermoplastic single-ply roof coverings shall comply with ASTM D 4434, ASTM D 6754, ASTM D 6878 or CAN/CGSB 37-54.
Ballasted thermoplastic low-slope roofs (roof slope < 2:12) shall be installed in accordance with this section and Section 1504.4. Stone used as ballast shall comply with ASTM D 448.
The installation of sprayed polyurethane foam roofing shall comply with the provisions of this section.
Sprayed polyurethane foam roofs shall have a slope designed and built to provide positive roof drainage.
Spray-applied polyurethane foam insulation shall comply with Type III or IV as defined in ASTM C 1029.
Foamed-in-place roof insulation shall be installed in accordance with the manufacturer's instructions. A liquid-applied protective coating that complies with Section 1507.15 shall be applied no less than 2 hours nor more than 72 hours following the application of the foam.
Foam plastic materials and installation shall comply with Chapter 26.
The installation of liquid-applied roofing shall comply with the provisions of this section.
Liquid-applied roofing shall have a slope designed and built to provide positive roof drainage.
Liquid-applied roofing shall comply with ASTM C 836, ASTM C 957, ASTM D 1227, ASTM D 3468, ASTM D 6083, ASTM D 6694 or ASTM D 6947.
The green roof system shall comply with the provisions of this section.
Green roof systems shall comply with ANSI/SPRI RP-14 and ANSI/SPRI VF-1, or with FM DS 1-35.

Exceptions:

1. The aggregate area of landscaping materials or growth media or both on any single roof level of a building or structure is 250 square feet (23.2 m2) or less.

2. The roof area is 22 feet (6706 mm) or less from grade.

3. The green roof system is a container garden.
The roof structure shall comply with Chapter 16 for the design of the green roofs system.
Roof covering shall comply with Section 1507.10, 1507.11, 1507.12, 1507.13, or 1507.15.
The roofing membrane shall have a design slope in accordance with the roof covering utilized. Overburden shall be installed to prevent slippage.
The use of above-deck thermal insulation shall be permitted provided such insulation is covered with an approved roof covering and passes the tests of FM 4450 or UL 1256 when tested as an assembly.

Exceptions:

1. Foam plastic roof insulation shall conform to the material and installation requirements of Chapter 26.

2. Where a concrete roof deck is used and the above-deck thermal insulation is covered with an approved roof covering.
Cellulosic fiberboard roof insulation shall conform to the material and installation requirements of Chapter 23.
Above-deck thermal insulation board shall comply with the standards in Table 1508.2.

TABLE 1508.2 MATERIAL STANDARDS FOR ROOF INSULATION

Cellular glass board ASTM C 552
Composite boards ASTM C 1289, Type III, IV, V or VI
Expanded polystyrene ASTM C 578
Extruded polystyrene board ASTM C 578
Perlite board ASTM C 728
Polyisocyanurate board ASTM C 1289, Type I or Type II
Wood fiberboard ASTM C 208
The provisions of this section shall govern the construction of rooftop structures. All rooftop structures shall be subject to the roof area coverage limitations and building height requirements of Chapter 5. Rooftop structures shall be constructed with materials as required for the building, except as provided for in this section.
Bulkheads and penthouses shall comply with the construction requirements of Section 1509.2.
Bulkheads and penthouses shall be constructed with walls, floors and roof as required for the building.

Exceptions: Where the total aggregate area of all rooftop structures does not exceed 33 percent of the area of the roof of the building upon which they are erected; the following shall apply:

1. Bulkheads on buildings of Type I and II construction. The exterior walls and roofs of such bulkheads with a fire separation distance of more than 5 feet (1524 mm) and less than 30 feet (9144 mm) shall be of at least 1-hour fire-resistance-rated noncombustible construction. Walls and roofs with a fire separation distance of 30 feet (9144 mm) or greater shall be of noncombustible construction. Interior framing and walls shall be of noncombustible construction.

2. Bulkheads on buildings of Type III, IV and V construction. The exterior walls of such bulkheads with a fire separation distance of more than 5 feet (1524 mm) and less than 30 feet (9144 mm) shall be at least 1-hour fire-resistance-rated construction. Walls with a fire separation distance of 30 feet (9144 mm) or greater from a common property line shall be of Type IV construction, or noncombustible construction. Roofs shall be constructed of materials and fire-resistance rated as required in Table 601 . Interior framing and walls shall be Type IV or noncombustible or fire-retardant-treated wood construction.

3. On one-story buildings, combustible unroofed mechanical equipment screens, fences or similar enclosures are permitted where located with a fire separation distance of at least 20 feet (6096 mm) from adjacent property lines and where not exceeding 4 feet (1219 mm) in height above the roof surface.
Enclosed walls of penthouses shall comply with the requirements for exterior walls as per Tables 601 and 602 for the construction class of the building on which they are erected. Roofs of penthouses shall comply with the requirements for roof construction of Table 601 and Chapter 15 of this code.
An enclosed rooftop structure not intended for human occupancy shall not be used for purposes other than shelter of mechanical equipment or shelter of vertical shaft openings in the roof. Provisions, such as louvers, louver blades or flashing, shall be made to protect the mechanical equipment and the building interior from the elements.
Tanks having a capacity of more than 500 gallons (2 m3) placed in or on a building shall be supported on masonry, reinforced concrete, steel or Type IV construction provided that, where such supports are located in the building above the lowest story, the support shall be fire-resistance rated as required for Type IA construction.
Such tanks shall have in the bottom or on the side near the bottom, a pipe or outlet, fitted with a suitable quick opening valve for discharging the contents in an emergency through an adequate drain.
Such tanks shall not be placed over or near a line of stairs or an elevator shaft, unless there is a solid roof or floor underneath the tank.
Unenclosed roof tanks shall have covers sloping toward the outer edges.
Cooling towers in excess of 250 square feet (23.2 m2) in base area or in excess of 15 feet (4572 mm) high where located on building roofs more than 50 feet (15 240 mm) high shall be of noncombustible construction.

Exceptions:

1. Drip boards and the enclosing construction of wood not less than 1 inch (25 mm) nominal thickness, provided the wood is covered on the exterior of the tower with noncombustible material.

2. Fill and drift eliminators may be of combustible material if the towers are provided with automatic sprinkler protection complying with Section 903 of this code.

3. Fill and drift eliminators that comply with Section 908 of the New York City Mechanical Code.
Any steeple, minaret, spire, dome or cupola shall be of a type of construction not less in fire-resistance rating than required for the building to which it is attached except that any such steeple, minaret, spire, dome or cupola that exceeds 85 feet (25 908 mm) in height above grade plane, exceeds 200 square feet (18.6 m2) in horizontal area or is used for any purpose other than a belfry or an architectural embellishment shall be constructed of and supported on Type I or II construction.
Any steeple, minaret, spire, dome or cupola that exceeds 60 feet (18 288 mm) in height above the highest point at which it comes in contact with the roof, or that exceeds 200 square feet (18.6 m2) in area at any horizontal section, or which is intended to be used for any purpose other than a belfry or architectural embellishment, shall be entirely constructed of and supported by noncombustible materials. Such structures shall be separated from the building below by construction having a fire-resistance rating of not less than 1.5 hours with openings protected with a minimum 1.5-hour fire-protection rating. Such structures placed above the roof of any building more than 50 feet (15 240 mm) in height, shall be of noncombustible material and shall be supported by construction of noncombustible material.
Steeples, minarets, and spires where enclosed shall have exterior walls as required for the building to which they are attached. The roof covering of spires shall be of a class of roof covering as required for the main roof of the rest of the structure.
Dormers shall have exterior walls as required for the building to which they are attached. The roof covering of dormers shall be of a class of roof covering as required for the main roof of the rest of the structure.
Greenhouses used for the cultivation of plants, on the roofs of buildings other than buildings of Type V construction, shall be constructed of noncombustible framework and shall be glazed with plain or wire glass, or light transmitting plastic glazing complying with the requirements of Section 2606. The floors of greenhouses shall be constructed to be at least equal to the requirements for roof construction on Table 601 for the construction class of the building on which it is located.
Buildings greater than 22 feet (6706 mm) in height with roof slopes less than 2.4 units vertical in 12 units horizontal (20-percent slope) shall be provided with a parapet, railing, fence, or combination thereof, not less than 42 inches (1067 mm) in height. Railings or fences may be located inward from the face of the exterior wall a distance not exceeding 6 feet (1829 mm). Railings or fences shall be of noncombustible material, except on buildings of Type V construction. Railings shall be constructed to comply with the requirements of Sections 1012 and 1607.7.
Rooftops used for recreational purposes shall be provided with wire fencing at least 10 feet (3048 mm) in height. Openings in the fence shall not permit the passage of a 4-inch diameter (102 mm) sphere. Where ball games are played on rooftops the wire fencing shall be extended to provide an overhead closure.
The following roof structures may be constructed of combustible material if less than 12 feet (1658 mm) high above the roof: antenna supports; flagpoles; clothes drying frames; duckboarding, decking or platforms that do not cover more than 20 percent of the contiguous roof area at that level.
Rooftop mounted photovoltaic systems shall be designed in accordance with this section.
Rooftop mounted photovoltaic systems shall be designed for wind loads for component and cladding in accordance with Chapter 16 using an effective wind area based on the dimensions of a single unit frame.
Rooftop mounted photovoltaic systems shall have the same fire classification as the roof assembly required by Section 1505.
Rooftop mounted photovoltaic systems shall be installed in accordance with the manufacturer's installation instructions.
Photovoltaic panels and modules mounted on top of a roof shall be listed and labeled in accordance with UL 1703 and shall be installed in accordance with the manufacturer's installation instructions.
Materials and methods of application used for recovering or replacing an existing roof covering shall comply with the requirements of Chapter 15.

Exception: Section 1504.9 shall not apply if the area to be recovered or replaced is less than 50 percent of the roof area and less than 500 square feet (46 m2).
Reroofs shall provide positive drainage.
Structural roof components shall be capable of supporting the roof-covering system and the material and equipment loads that will be encountered during installation of the system.
New roof coverings shall not be installed without first removing all existing layers of roof coverings down to the roof deck where any of the following conditions occur:

1. Where 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. Where the existing roof covering is wood shake, slate, clay, cement or asbestos-cement tile.

3. Where the existing roof has two or more applications of any type of roof covering.

Exceptions:

1. Complete and separate roofing systems, such as standing-seam metal roof 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.

2. 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 1510.4.

3. The application of a new protective coating over an existing spray polyurethane foam roofing system shall be permitted without tear-off of existing roof coverings.
Where the application of a new roof covering over wood shingle or shake roofs creates a combustible concealed space, the entire existing surface shall be covered with gypsum board, mineral fiber, glass fiber or other approved materials securely fastened in place.
Existing slate, clay or cement tile shall be permitted for reinstallation, except that damaged, cracked or broken slate or tile shall not be reinstalled. Existing vent flashing, metal edgings, drain outlets, collars and metal counterflashings shall not be reinstalled where rusted, damaged or deteriorated. Aggregate surfacing materials shall not be reinstalled.
Flashings shall be reconstructed in accordance with approved manufacturer's installation instructions. Metal flashing to which bituminous materials are to be adhered shall be primed prior to installation.
Solar photovoltaic panels/modules installed upon a roof or as an integral part of a roof assembly shall comply with the requirements of this code and the New York City Fire Code.
The structural frame and roof construction supporting the load imposed upon the roof by the photovoltaic panels/modules shall comply with the requirements of Table 601.
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