N.Y.C. Admin. Code § BC 1507: Section BC 1507: Requirements for Roof Coverings

1507.1 Scope.

Roof coverings shall be applied in accordance with the applicable provisions of this section and the manufacturer's instructions.

1507.2 Asphalt shingles.

The installation of asphalt shingles shall comply with the provisions of this section.

1507.2.1 Deck requirements.

Asphalt shingles shall be fastened to solidly sheathed decks.

1507.2.2 Slope.

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.

1507.2.3 Underlayment.

Unless otherwise noted, required underlayment shall conform to ASTM D 226, Type I, ASTM D 4869, Type I, or ASTM D 6757.

1507.2.4 Self-adhering polymer modified bitumen sheet.

Self-adhering polymer modified bitumen sheet shall comply with ASTM D 1970.

1507.2.5 Asphalt shingles.

Asphalt shingles shall comply with ASTM D 225 or ASTM D 3462.

1507.2.6 Fasteners.

Fasteners for asphalt shingles shall be galvanized, stainless steel, aluminum or copper roofing nails, minimum 12-gage (0.105-inch (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.

1507.2.7 Attachment.

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.

1507.2.8 Underlayment application.

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 (482.6 mm) wide strip of underlayment felt parallel with and starting at the eaves, fastened sufficiently to hold in place. Starting at the eave, apply 36-inch (914.4 mm) wide sheets of underlayment overlapping successive sheets 19 inches (482.6 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 (50.8 mm), fastened only as necessary to hold in place. Distortions in the underlayment shall not interfere with the ability of the shingles to seal.

1507.2.8.1 Ice barrier.

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 (609.6 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.

1507.2.9 Flashings.

Flashing for asphalt shingles shall comply with this section. Flashing shall be applied in accordance with this section and the asphalt shingle manufacturer's instructions.

1507.2.9.1 Base and cap flashing.

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/m

2

). Cap flashing shall be corrosion-resistant metal of minimum nominal 0.019-inch (0.483 mm) thickness.

1507.2.9.2 Valleys.

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 (609.6 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 (457.2 mm) and the top layer a minimum of 36 inches (914.4 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 (914.4 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 square 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 square ft.

Lead

—

—

2.5 pounds

Lead-coated copper

0.0216 in.

—

ASTM B 101, 16 oz. per square ft.

Lead-coated high-yield copper

0.0162 in.

—

ASTM B 101, 12 oz. per square 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, 1 square foot = 0.0929 m

2

.

1507.2.9.3 Drip edge.

A drip edge shall be provided at eaves and rake edges of shingle roofs. Adjacent segments of the drip edge shall be lapped a minimum of 2 inches (50.8 mm). The vertical leg of drip edges shall be a minimum of 1 1/2 inches (38.1 mm) in width and shall extend a minimum of 1/4 inch (6.4 mm) below sheathing. The drip edge shall extend back on the roof a minimum of 2 inches (50.8 mm). Underlayment shall be installed over drip edges along eaves. Drip edges shall be installed over underlayment along rake edges. Drip edges shall be mechanically fastened a maximum of 12 inches (304.8 mm) on center.

1507.3 Clay and concrete tile.

The installation of clay and concrete tile shall comply with the provisions of this section.

1507.3.1 Deck requirements.

Concrete and clay tile shall be installed only over solid sheathing or spaced structural sheathing boards.

1507.3.2 Deck slope.

Clay and concrete roof tile shall be installed on roof slopes of 2 1/2 units vertical in 12 units horizontal (21-percent slope) or greater. For roof slopes from 2 1/2 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.

1507.3.3 Underlayment.

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.

1507.3.3.1 Low-slope roofs.

For roof slopes from 2 1/2 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 (482.6 mm) strip of underlayment shall be applied parallel with the eave and fastened sufficiently in place.

2. Starting at the eave, 36-inch (914.4 mm) wide strips of underlayment felt shall be applied overlapping successive sheets 19 inches (482.6 mm) and fastened sufficiently in place.

1507.3.3.2 High-slope roofs.

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 (50.8 mm), fastened only as necessary to hold in place.

1507.3.4 Clay tile.

Clay roof tile shall comply with ASTM C 1167.

1507.3.5 Concrete tile.

Concrete roof tile shall comply with ASTM C 1492.

1507.3.6 Fasteners.

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 be not less than 0.083 inch (2.1 mm). Perimeter fastening areas include three tile courses but not less than 36 inches (914.4 mm) from either side of hips or ridges and edges of eaves and gable rakes.

1507.3.7 Attachment.

Clay and concrete roof tiles shall be fastened in accordance with Table 1507.3.7.

Table 1507.3.7 Clay and Concrete Tile Attachment

a, b, c

General – Clay or Concrete Roof Tile

Maximum Nominal Design Wind Speed, V

asd

f

(mph)

Mean roof height (feet)

Roof slope

£

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 1609.5.3.

120

0 - 60

The fastening system shall resist the wind forces in Section 1609.5.3.

130

0 - 60

The fastening system shall resist the wind forces in Section 1609.5.3.

All

> 60

The fastening system shall resist the wind forces in Section 1609.5.3.

Interlocking Clay or Concrete Roof Tile with Projecting Anchor Lugs

d, e

(Installations on spaced/solid sheathing with battens or spaced sheathing)

Maximum Nominal Design Wind Speed, V

asd

f

(mph)

Mean roof height (feet)

Roof slope < 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' mastic.

110

0 - 60

The fastening system shall resist the wind forces in 1609.5.3.

120

0 - 60

The fastening system shall resist the wind forces in 1609.5.3.

130

0 - 60

The fastening system shall resist the wind forces in 1609.5.3.

All

> 60

The fastening system shall resist the wind forces in 1609.5.3.

Interlocking Clay or Concrete Roof Tile with Projecting Anchor Lugs (Installations on solid sheathing without battens)

Maximum Nominal Design Wind Speed, V

asd

f

(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' mastic.

110

0 - 60

The fastening system shall resist the wind forces in 1609.5.3.

120

0 - 60

The fastening system shall resist the wind forces in 1609.5.3.

130

0 - 60

The fastening system shall resist the wind forces in 1609.5.3.

All

> 60

The fastening system shall resist the wind forces in 1609.5.3.

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 = 4.882kg/m

2

.

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 1 inch 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.

f. V

asd

shall be determined in accordance with Section 1609.3.1.

1507.3.8 Application.

Tile shall be applied according to the manufacturer's instructions, based on the following:

1. Climatic conditions.

2. Roof slope.

3. Underlayment system.

4. Type of tile being installed.

1507.3.9 Flashing.

At the juncture of the roof vertical surfaces, flashing and counterflashing shall be provided in accordance with the manufacturer's 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 (24.5 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 (101.6 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 (914.4 mm) wide 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.

1507.4 Metal roof panels.

The installation of metal roof panels shall comply with the provisions of this section.

1507.4.1 Deck requirements.

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.

1507.4.2 Deck slope.

The minimum slope for metal roof panels shall comply with the following:

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

3. The minimum slope for standing-seam metal roof panel systems shall be one-quarter unit vertical in 12 units horizontal (2-percent slope).

1507.4.3 Material standards.

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 pre-formed 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 instructions.

Zinc

0.027 inch minimum thickness; 99.995% electrolytic 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 = 0.305 kg/m

2

, 1 pound per square foot = 4.882 kg/m

2

, 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

Material

Standard

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 755

a

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.

1507.4.4 Attachment.

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.

4. Aluminum fasteners are acceptable for aluminum roofs attached to aluminum supports.

1507.5 Metal roof shingles.

The installation of metal roof shingles shall comply with the provisions of this section.

1507.5.1 Deck requirements.

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.

1507.5.2 Deck slope.

Metal roof shingles shall not be installed on roof slopes below three units vertical in 12 units horizontal (25-percent slope).

1507.5.3 Underlayment.

Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869.

1507.5.4 Ice barrier.

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.

1507.5.5 Material standards.

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).

1507.5.6 Attachment.

Metal roof shingles shall be secured to the roof in accordance with the manufacturer's instructions.

1507.5.7 Flashing.

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 (203.2 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 (101.6 mm). The metal valley flashing shall have a 36-inch (914.4 mm) wide 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 underlayment shall be solid cemented to the roofing underlayment or a self-adhering polymer modified bitumen sheet shall be installed.

1507.6 Mineral-surfaced roll roofing.

The installation of mineral-surfaced roll roofing shall comply with this section.

1507.6.1 Deck requirements.

Mineral-surfaced roll roofing shall be fastened to solidly sheathed roofs.

1507.6.2 Deck slope.

Mineral-surfaced roll roofing shall not be applied on roof slopes below one unit vertical in 12 units horizontal (8-percent slope).

1507.6.3 Underlayment.

Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869.

1507.6.4 Ice barrier.

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 (609.6 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.

1507.6.5 Material standards.

Mineral-surfaced roll roofing shall conform to ASTM D 3909 or ASTM D 6380.

1507.7 Slate shingles.

The installation of slate shingles shall comply with the provisions of this section.

1507.7.1 Deck requirements.

Slate shingles shall be fastened to solidly sheathed roofs.

1507.7.2 Deck slope.

Slate shingles shall only be used on slopes of four units vertical in 12 units horizontal (4:12) or greater.

1507.7.3 Underlayment.

Underlayment shall comply with ASTM D 226, Type II or ASTM D 4869, Type III or IV.

1507.7.4 Ice barrier.

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 (609.6 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.

1507.7.5 Material standards.

Slate shingles shall comply with ASTM C 406.

1507.7.6 Application.

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 ³ 20:12

2

For SI: 1 inch = 25.4 mm.

1507.7.7 Flashing.

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 (101.6 mm) wide strip of felt set in plastic cement and extending 1 inch (25.4 mm) above the first felt and a top coating of plastic cement. The felt shall extend over the base flashing 2 inches (50.8 mm).

1507.8 Wood shingles.

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 not less than three units vertical in 12 units horizontal (3:12).

Wood shakes shall be installed on slopes of not less than four units vertical in 12 units horizontal (4:12).

2. Deck requirement

Temperate climate

Shingles shall be applied to roofs with solid or spaced sheathing. Where spaced sheathing is used, sheathing boards shall be not less than 1" × 4" nominal dimensions and shall be spaced on centers 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 be not less than 1" × 4" nominal dimensions and shall be spaced on centers equal to the weather exposure to coincide with the placement of fasteners. When1" × 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 galvanized 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 galvanized or Type 304 (Type 316 for coastal areas) 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.

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 taper sawn shakes of naturally durable wood and shall be 0.25 to 0.375 inch for preservative-treated 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.

1507.8.1 Deck requirements.

Wood shingles shall be installed on solid or spaced sheathing. Where spaced sheathing is used, sheathing boards shall be not less than 1-inch by 4-inch (25.4 mm by 101.6 mm) nominal dimensions and shall be spaced on centers equal to the weather exposure to coincide with the placement of fasteners.

1507.8.1.1 Solid sheathing required.

Solid sheathing is required.

1507.8.2 Deck slope.

Wood shingles shall be installed on slopes of not less than three units vertical in 12 units horizontal (25-percent slope).

1507.8.3 Underlayment.

Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869.

1507.8.4 Ice barrier.

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 (609.6 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.

1507.8.5 Material standards.

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

1507.8.6 Attachment.

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.

1507.8.7 Application.

Wood shingles shall be laid with a side lap not less than 1 1/2 inches (38.1 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 No. 2 No. 3

3.75 3.5 3

5 4 3.5

18

No. 1 No. 2 No. 3

4.25 4 3.5

5.5 4.5 4

24

No. 1 No. 2 No. 3

5.75 5.5 5

7.5 6.5 5.5

For SI: 1 inch = 25.4 mm.

1507.8.8 Flashing.

At the juncture of the roof and vertical surfaces, flashing and counterflashing shall be provided in accordance with the manufacturer's instructions, and where of metal, shall be not 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 (25.4 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 (101.6 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 (914.4 mm) wide 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.

1507.9 Wood shakes.

The installation of wood shakes shall comply with the provisions of this section and Table 1507.8.

1507.9.1 Deck requirements.

Wood shakes shall only be used on solid or spaced sheathing. Where spaced sheathing is used, sheathing boards shall be not less than 1-inch by 4-inch (25.4 mm by 101.6 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 (25.4 mm by 101.6 mm) spaced sheathing is installed at 10 inches (254 mm) on center, additional 1-inch by 4-inch (25.4 mm by 101.6 mm) boards shall be installed between the sheathing boards.

1507.9.1.1 Solid sheathing required.

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.

1507.9.2 Deck slope.

Wood shakes shall only be used on slopes of not less than four units vertical in 12 units horizontal (33-percent slope).

1507.9.3 Underlayment.

Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869.

1507.9.4 Ice barrier.

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 (609.6 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.

1507.9.5 Interlayment.

Interlayment shall comply with ASTM D 226, Type I.

1507.9.6 Material standards.

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 shingles of naturally durable wood

1

CSSB

Fire-retardant-treated shakes and shingles of naturally durable wood

1

CSSB

Preservative-treated taper sawn shakes of Southern pine treated in accordance with AWPA U1 (Commodity Specification 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.

1507.9.7 Attachment.

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.

1507.9.8 Application.

Wood shakes shall be laid with a side lap not less than 1 1/2 inches (38.1 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

10

a

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.

1507.9.9 Flashing.

At the juncture of the roof and vertical surfaces, flashing and counterflashing shall be provided in accordance with the manufacturer's instructions, and where of metal, shall be not 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 (25.4 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 (101.6 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 (914.4 mm) wide 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.

1507.10 Built-up roofs.

The installation of built-up roofs shall comply with the provisions of this section.

1507.10.1 Slope.

Built-up roofs shall have a slope designed and built to provide positive roof drainage.

1507.10.2 Material standards.

Built-up roof covering materials shall comply with UL 55A or the standards in Table 1507.10.2 of this code.

Table 1507.10.2 Built-Up Roofing Material Standards

Material Standard

Standard 

Acrylic coating 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 D 1227; D 2823; D 2824; 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, dampproofing 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

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 membrane roofs shall have a slope designed and built to provide positive roof drainage.

1507.11.2 Material standards.

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 or ASTM D 6509.

1507.12 Thermoset single-ply roofing.

The installation of thermoset single-ply roofing shall comply with the provisions of this section.

1507.12.1 Slope.

Thermoset single-ply membrane roofs shall have a slope designed and built to provide positive roof drainage.

1507.12.2 Material standards.

Thermoset single-ply roof coverings shall comply with ASTM D 4637, ASTM D 5019 or CGSB 37-GP-52M.

1507.12.3 Ballasted thermoset low-slope roofs.

Ballasted thermoset low-slope roofs (roof slope < 2:12) shall be installed in accordance with this section and Section 1504.4, and subject to the limitations of Section 1504.8.

1507.13 Thermoplastic single-ply roofing.

The installation of thermoplastic single-ply roofing shall comply with the provisions of this section.

1507.13.1 Slope.

Thermoplastic single-ply membrane roofs shall have a slope designed and built to provide positive roof drainage.

1507.13.2 Material standards.

Thermoplastic single-ply roof coverings shall comply with ASTM D 4434, ASTM D 6754, ASTM D 6878 or CAN/CGSB 37-54.

1507.13.3 Ballasted thermoplastic low-slope roofs.

Ballasted thermoplastic low-slope roofs (roof slope < 2:12) shall be installed in accordance with this section and Section 1504.4, and subject to the limitations of Section 1504.8.

1507.14 Sprayed polyurethane foam roofing.

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

1507.14.1 Slope.

Sprayed polyurethane foam roofs shall have a slope designed and built to provide positive roof drainage.

1507.14.2 Material standards.

Spray-applied polyurethane foam insulation shall comply with Type III or IV as defined in ASTM C 1029.

1507.14.3 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 1507.14.3 shall be applied no less than 2 hours nor more than 72 hours following the application of the foam.

Table 1507.14.3 Protective Coating Material Standards

Material Standard

Standard 

Acrylic coating

ASTM D 6083

Silicone coating

ASTM D 6694

Moisture-cured polyurethane coating

ASTM D 6947

1507.14.4 Foam plastics.

Foam plastic materials and installation shall comply with Chapter 26.

1507.15 Liquid-applied roofing.

The installation of liquid-applied roofing shall comply with the provisions of this section.

1507.15.1 Slope.

Liquid-applied roofing shall have a slope designed and built to provide positive roof drainage.

1507.15.2 Material standards.

Liquid-applied roofing shall comply with ASTM C 836, ASTM C 957, ASTM D 1227 or ASTM D 3468, ASTM D 6083, ASTM D 6694 or ASTM D 6947.

1507.16 Vegetative roofs, roof gardens and landscaped roofs.

Vegetative roofs, roof gardens and landscaped roofs shall comply with the provisions of this section and New York City Fire Code.

1507.16.1 Design standards.

Vegetative roofs, roof gardens and landscaped roofs shall comply with ANSI/SPRI RP-14 and ANSI/SPRI VF-1, or with FM DS 1-35.

Exceptions: 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 m

2

)or less.

1. The roof area is 22 feet (6705.6 mm) or less from grade.

2. The vegetative roof system is a container garden.

1507.16.2 Roof structure.

The roof structure shall comply with Chapter 16 for the design of the vegetative roofs, roof gardens and landscaped roofs.

1507.16.3 Roof covering.

Roof covering shall comply with Section 1507.10, 1507.11, 1507.12, 1507.13 or 1507.15.

1507.16.4 Slope.

The roofing membrane shall have a design slope in accordance with the roof covering utilized. Overburden shall be installed to prevent slippage.

1507.16.5 Structural fire resistance.

The structural frame and roof construction supporting the load imposed upon the roof by the vegetative roof, roof gardens or landscaped roofs shall comply with the requirements of Table 601.

1507.17 Photovoltaic shingles.

The installation of photovoltaic shingles shall comply with the provisions of this section.

1507.17.1 Deck requirements.

Photovoltaic shingles shall be applied to a solid or closely fitted deck, except where the shingles are specifically designed to be applied over spaced sheathing.

1507.17.2 Deck slope.

Photovoltaic shingles shall not be installed on roof slopes less than three units vertical in 12 units horizontal (25-percent slope).

1507.17.3 Underlayment.

Unless otherwise noted, required underlayment shall conform to ASTM D 226, ASTM D 4869 or ASTM D 6757.

1507.17.4 Underlayment application.

Underlayment shall be applied shingle fashion, parallel to and starting from the eave, lapped 2 inches (50.8 mm) and fastened sufficiently to hold in place.

1507.17.4.1 High wind attachment.

Underlayment applied in areas subject to high winds (V

asd

greater than 110 mph (49.1 m/s) as determined in accordance with Section 1609.3.1) shall be applied with corrosion-resistant fasteners in accordance with the manufacturer's instructions. Fasteners shall be applied along the overlap at not more than 36 inches (914.4 mm) on center. Underlayment installed where V

asd

is not less than 120 mph (53.6 m/s) shall comply with ASTM D 226, Type II, ASTM D 4869, Type IV or ASTM D 6757. The underlayment shall be attached in a grid pattern of 12 inches (304.8 mm) between side laps with a 6-inch (152.4 mm) spacing at the side laps. Underlayment shall be applied in accordance with Section 1507.2.8 except all laps shall be a minimum of 4 inches (101.6 mm). Underlayment shall be attached using metal or plastic cap nails with a head diameter of not less than 1 inch (25.4 mm) with a thickness of not less than 32-gage (0.0134 inch (0.34 mm)) sheet metal. The cap nail shank shall be a minimum of 12 gage (0.105 inch (2.67 mm)) with a length to penetrate through the roof sheathing or a minimum of 3/4 inch (19.1 mm) into the roof sheathing.

Exception: As an alternative, adhered underlayment complying with ASTM D 1970 shall be permitted.

1507.17.4.2 Ice barrier.

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 instead of normal underlayment and extend from the lowest edges of all roof surfaces to a point not less than 24 inches (609.6 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.

1507.17.5 Fasteners.

Fasteners for photovoltaic shingles shall be galvanized, stainless steel, aluminum or copper roofing nails, minimum 12-gage (0.105 inch (2.67 mm)) shank with a minimum 3/8-inch (9.5 mm) diameter 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.

1507.17.6 Material standards.

Photovoltaic shingles shall be listed and labeled in accordance with UL 1703.

1507.17.7 Attachment.

Photovoltaic shingles shall be attached in accordance with the manufacturer's instructions.

1507.17.8 Wind resistance.

Photovoltaic shingles shall be tested in accordance with procedures and acceptance criteria in ASTM D 3161. Photovoltaic shingles shall comply with the classification requirements of Table 1504.1.1 of this code for the appropriate maximum nominal design wind speed. Photovoltaic shingle packaging shall bear a label to indicate compliance with the procedures in ASTM D 3161 and the required classification from Table 1504.1.1 of this code.