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CHAPTER 15 ROOF ASSEMBLIES AND ROOFTOP STRUCTURES

ROOF COVERING. The covering applied to the roof deck SECTION 1501 for weather resistance, fire classification or appearance. GENERAL 1501.1 Scope. The provisions of this chapter shall govern the ROOF COVERING SYSTEM. See “Roof assembly.” design, materials, construction and quality of roof assemblies, ROOF DECK. The flat or sloped surface not including its sup- and rooftop structures. porting members or vertical supports. ROOF RECOVER. The process of installing an additional roof covering over a prepared existing roof covering without SECTION 1502 removing the existing roof covering. DEFINITIONS 1502.1 General. The following words and terms shall, for the ROOF REPAIR. Reconstruction or renewal of any part of an purposes of this chapter and as used elsewhere in this code, existing roof for the purposes of its maintenance. have the meanings shown herein. ROOF REPLACEMENT. The process of removing the exist- BUILT-UP ROOF COVERING. Two or more layers of felt ing roof covering, repairing any damaged substrate and install- cemented together and surfaced with a cap sheet, mineral ag- ing a new roof covering. gregate, smooth coating or similar surfacing material. ➡ ROOF VENTILATION. The natural or mechanical process INTERLAYMENT. A layer of felt or nonbituminous satu- of supplying conditioned or unconditioned air to, or removing rated felt not less than 18 inches (457 mm) wide, shingled be- such air from, attics, cathedral ceilings or other enclosed tween each course of a wood-shake roof covering. spaces over which a roof assembly is installed. MECHANICAL EQUIPMENT SCREEN. A partially en- ROOFTOP STRUCTURE. An enclosed structure on or closed rooftop structure used to aesthetically conceal heating, above the roof of any part of a building. ventilating and air conditioning (HVAC) electrical or mechani- SCUPPER. An opening in a wall or parapet that allows water cal equipment from view. to drain from a roof. METAL ROOF PANEL. An interlocking metal sheet having a 2 SINGLE-PLY MEMBRANE. A roofing membrane that is minimum installed weather exposure of 3 square feet (.279 m ) field applied using one layer of membrane material (either ho- per sheet. mogeneous or composite) rather than multiple layers. METAL ROOF SHINGLE. An interlocking metal sheet hav- UNDERLAYMENT. One or more layers of felt, sheathing pa- ing an installed weather exposure less than 3 square feet (.279 2 per, nonbituminous saturated felt or other approved material m ) per sheet. over which a steep-slope roof covering is applied. 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 SECTION 1503 or held in place with an approved ballast layer. WEATHER PROTECTION PENTHOUSE. An enclosed, unoccupied structure above the 1503.1 General. Roof decks shall be covered with approved roof of a building, other than a tank, tower, spire, dome cupola roof coverings secured to the building or structure in accor- or bulkhead, occupying not more than one-third of the roof dance with the provisions of this chapter. Roof coverings shall area. be designed, installed and maintained in accordance with this POSITIVE ROOF DRAINAGE. The drainage condition in code and the approved manufacturer’s instructions such that which consideration has been made for all loading deflections the roof covering shall serve to protect the building or structure. of the roof deck, and additional slope has been provided to en- 1503.2 Flashing. Flashing shall be installed in such a manner sure drainage of the roof within 48 hours of precipitation. so as to prevent moisture entering the wall and roof through REROOFING. The process of recovering or replacing an ex- joints in copings, through moisture-permeable materials and at isting roof covering. See “Roof recover” and “Roof replace- intersections with parapet walls and other penetrations through ment.” the roof plane. ROOF ASSEMBLY. A system designed to provide weather 1503.2.1 Locations. Flashing shall be installed at wall and protection and resistance to design loads. The system consists roof intersections, at gutters, wherever there is a change in of a roof covering and roof deck or a single component serving roof slope or direction and around roof openings. Where as both the roof covering and the roof deck. A roof assembly in- flashing is of metal, the metal shall be corrosion resistant cludes the roof deck, vapor retarder, substrate or thermal bar- with a thickness of not less than 0.019 inch (.483 mm) (No. rier, insulation, vapor retarder and roof covering. 26 galvanized sheet).

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ROOF ASSEMBLIES AND ROOFTOP STRUCTURES

1503.3 Coping. Parapet walls shall be properly coped with 1504.2 Wind resistance of clay and concrete tile. Clay and noncombustible, weatherproof materials of a width no less concrete tile roof coverings shall be connected to the roof deck than the thickness of the parapet wall. in accordance with Chapter 16. 1503.4 Roof drainage. Design and installation of roof drain- 1504.3 Wind resistance of nonballasted roofs. Roof cover- age systems shall comply with this section and the Arizona ings installed on roofs in accordance with Section 1507 that are State Plumbing Code. mechanically attached or adhered to the roof deck shall be de- signed to resist the design wind load pressures for cladding in 1503.4.1 Primary roof drainage systems. A primary roof Chapter 16. drainage system shall be provided. 1503.4.1.1 Design. The design rainfall rate (inches per 1504.3.1 Other roof systems. Roof systems with built-up, hour) shall be not less than 6 inches (152 mm) per hour. modified bitumen, fully adhered or mechanically attached single-ply through fastened metal panel roof systems, and 1503.4.2 Secondary roof drainage systems. A secondary other types of membrane roof coverings shall also be tested roof drainage system shall be provided, as follows: in accordance with FM 4450, FM 4470, UL 580 or UL 1897. 1. The design rainfall rate (inches per hour) shall be not 1504.3.2 Metal panel roof systems. Metal panel roof sys- less than 6 inches (152 mm) per hour. tems through fastened or standing seam shall be tested in ac- 2. The secondary drainage system shall be completely cordance with UL 580 or ASTM E 1592. independent of the primary roof drainage system. 1504.4 Ballasted low-slope roof systems. Ballasted low-slope 3. The roof design load shall include the weight of rain- (roof slope < 2:12) single-ply roof system coverings installed water up to the height above the drainage inlet that is in accordance with Section 1507 shall be designed in accor- required to achieve the secondary drainage design ca- dance with ANSI/SPRI RP-4. pacity, taking into consideration potential ponding re- sulting from roof deflection. 1504.5 Edge securement for low-slope roofs. Low-slope membrane roof systems metal edge securement, except gutters, 4. Where wall scuppers or interior drains are used for installed in accordance with Section 1507, shall be designed in secondary drainage, the base of the secondary drain- accordance with ANSI/SPRI ES-1, except the basic wind age inlets shall be a maximum of 2 inches (51 mm) speed shall be determined from Figure 1609. above the base of the primary drainage inlets with a minimum separation of 12 inches (305 mm). 1504.6 Physical properties. Roof coverings installed on < 5. Scuppers shall have a minimum opening width of 6 low-slope roofs (roof slope 2:12) in accordance with Section inches (152 mm) or three times the diameter of the 1507 shall demonstrate physical integrity over the working life calculated roof drain diameter, whichever is greater of the roof based upon 2,000 hours of exposure to accelerated and a minimum open height of 6 inches (152 mm). weathering tests conducted in accordance with ASTM G 152, The minimum height of the scuppers serving areas ASTM G 155 or ASTM G 154. Those roof coverings that are that may be occupied (sunroofs, balconies and decks) subject to cyclical flexural response due to wind loads shall not shall be 4 inches (102 mm). demonstrate any significant loss of tensile strength for unreinforced membranes or breaking strength for reinforced 1503.4.3 Gutters. Gutters and leaders placed on the outside membranes when tested as herein required. of buildings, other than Group R-3 as applicable in Section 101.2, private garages and buildings of Type V construc- 1504.7 Impact resistance. Roof coverings installed on tion, shall be of noncombustible material or a minimum of low-slope roofs (roof slope < 2:12) in accordance with Section Schedule 40 plastic pipe. 1507 shall resist impact damage based on the results of tests conducted in accordance with ASTM D 3746, ASTM D 4272, 1503.5 Roof ventilation. Intake and exhaust vents shall be pro- CGSB 37-GP-52M or FM 4470. vided in accordance with Section 1203.2 and the manufac- turer’s installation instructions.

SECTION 1505 FIRE CLASSIFICATION SECTION 1504 PERFORMANCE REQUIREMENTS 1505.1 General. Roof assemblies shall be divided into the 1504.1 Wind resistance of roofs. Roof decks and roof cover- classes defined below. Class A, B and C roof assemblies and ings shall be designed for wind loads in accordance with Chap- roof coverings required to be listed by this section shall be ter 16 and Sections 1504.2, 1504.3 and 1504.4. tested in accordance with ASTM E 108 or UL 790. In addition, ➡ fire-retardant-treated wood roof coverings shall be tested in ac- 1504.1.1 Wind resistance of asphalt shingles. Asphalt cordance with ASTM D 2898. The minimum roof coverings shingles shall be designed for wind speeds in accordance installed on buildings shall comply with Table 1505.1 based on with Section 1507.2.7. the type of construction of the building.

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TABLE 1505.1a MINIMUM ROOF COVERING CLASSIFICATION FOR TYPES OF CONSTRUCTION IA IB IIA IIB IIIA IIIB IV VA VB BBBCc BCc BBCc For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929 m2. > a. Nonclassified roof coverings shall be permitted on buildings of Group R-3, as applicable in Section 101.2, and Group U occupancies, where there is a minimum fire-separation distance of 6 feet measured from the leading edge of the roof. b. Buildings that are not more than two stories in height 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. 1505.2 Class A roof assemblies. Class A roof assemblies are those that are effective against severe fire test exposure. Class A roof assemblies and roof coverings shall be listed and identified as Class A by an approved testing agency. Class A roof assem- blies shall be permitted for use in buildings or structures of all types of construction. Exception: Class A roof assemblies include those with cov- erings of brick, masonry, slate, clay or concrete roof tile, ex- posed concrete roof deck, ferrous or copper shingles or sheets. 1505.3 Class B roof assemblies. Class B roof assemblies are those that are effective against moderate fire-test exposure. Class B roof assemblies and roof coverings shall be listed and identified as Class B by an approved testing agency. Exception: Class B roof assemblies include those with cov- erings of metal sheets and shingles. 1505.4 Class C roof assemblies. Class C roof assemblies are those that are effective against light fire-test exposure. Class C roof assemblies and roof coverings shall be listed and identified as Class C by an approved testing agency.

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254bR 2003 INTERNATIONAL BUILDING CODE®

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1505.5 Nonclassified roof ing. Nonclassified roofing is ap­ 1507.2.1 Deck re quire ments. Asphalt shin gles shall be fas­ proved mate rial that is not listed as a Class A, B or C roof cov er­ tened to solidly sheathed decks. ing. 1507.2.2 Slope. Asphalt shin gles shall only be used on roof 1505.6 Fire-re tar dant-treated wood shin gles and shakes. slopes of two units verti cal in 12 units hor i zon tal (17-per ­ Fire-retar dant-treated wood shakes and shingles shall be cent slope) or greater. For roof slopes from two units ver ti cal treated by impreg na tion with chemi cals by the full-cell vac­ in 12 units hori zon tal (17-per cent slope) up to four units ver­ uum-pressure pro cess, in ac cor dance with AWPA C1. Each tical in 12 units hor i zon tal (33-percent slope), dou ble bun dle shall be marked to identify the man u fac tured unit and underlayment ap pli ca tion is re quired in accor dance with the manu fac turer, and shall also be la beled to iden tify the clas­ Sec tion 1507.2.8. si fi ca tion of the mate rial in accor dance with the testing re­ 1507.2.3 Underlayment. Un less oth er wise noted, required quired in Section 1505.1, the treat ing com pany and the qual ity underlayment shall conform to ASTM D 226, Type I, or control agency. ASTM D 4869, Type I. 1505.7 Spe cial purpose roofs. Special purpose wood shin gle 1507.2.4 Self-ad her ing poly mer mod i fied bitu men sheet. or wood shake roofing shall con form with the grading and ap ­ Self-adher ing poly mer mod i fied bi tu men sheet shall com ­ pli ca tion re quire ments of Sec tion 1507.8 or 1507.9. In addi ­ ply with ASTM D 1970. tion, an underlayment of 0.625-inch (15.9 mm) Type X wa ter-re sis tant gypsum backing board or gyp sum sheathing 1507.2.5 Asphalt shingles. Asphalt shin gles shall have shall be placed under min i mum nom i nal 0.5-inch-thick (12.7 self-seal strips or be in ter lock ing, and comply with ASTM mm) wood struc tural panel solid sheathing or 1-inch (25 mm) D 225 or ASTM D 3462. nom i nal spaced sheath ing. 1507.2.6 Fasteners. Fas teners for asphalt shin gles shall be gal va nized, stain less steel, alumi num or copper roof ing nails, min i mum 12 gage [0.105 inch (2.67 mm)] shank with SECTION 1506 a mini mum 0.375 inch-di am e ter (9.5 mm) head, of a length MATERIALS to pene trate through the roofing mate ri als and a mini mum of 1506.1 Scope. The require ments set forth in this sec tion shall 0.75 inch (19.1 mm) into the roof sheathing. Where the roof ap ply to the ap pli ca tion of roof-cover ing mate ri als speci fied sheath ing is less than 0.75 inch (19.1 mm) thick, the nails herein. Roof cover ings shall be applied in accor dance with this shall pene trate through the sheathing. Fasteners shall com ­ chap ter and the man u fac turer’s instal la tion in struc tions. Instal ­ ply with ASTM F 1667. la tion of roof cover ings shall comply with the appli ca ble provi ­ 1507.2.7 At tach ment. Asphalt shingles shall have the min i- sions of Section 1507. mum number of fas ten ers required by the man u fac turer and 1506.2 Compat i bil ity of mate ri als. Roofs and roof cover ings Sec tion 1504.1. Asphalt shin gles shall be se cured to the roof shall be of mate ri als that are compat i ble with each other and with not less than four fas ten ers per strip shingle or two fas­ with the building or struc ture to which the mate ri als are ap­ teners per indi vid ual shingle. Where the roof slope exceeds plied. 20 units ver ti cal in 12 units hor i zon tal (166-per cent slope), special methods of fasten ing are re quired. For roofs lo cated 1506.3 Ma te rial speci fi ca tions and phys i cal char ac ter is tics. where the ba sic wind speed in accor dance with Fig ure 1609 Roof-cov er ing mate ri als shall conform to the appli ca ble stan ­ is 110 mph or greater, special meth ods of fasten ing are re ­ dards listed in this chap ter. In the absence of appli ca ble stan ­ quired. Special fasten ing methods shall be tested in accor - dards or where mate ri als are of ques tion able suitabil it y, testing dance with ASTM D 3161, mod i fied to use a wind speed of by an approved agency shall be required by the building of fi cial 110 mph. to de ter mine the char ac ter, qual ity and limi ta tions of appli ca ­ tion of the mate ri als. 1507.2.8 Underlayment ap pli ca tion. For roof slopes from two units ver ti cal in 12 units hor i zon tal (17-per cent slope), 1506.4 Product iden ti fi ca tion. Roof-cover ing mate ri als shall up to four units ver ti cal in 12 units hor i zon tal (33-per cent be deliv ered in pack ages bearing the man u fac turer’s identi fy ­ slope), underlayment shall be two lay ers applied in the fol­ ing marks and approved testing agency labels re quired in ac ­ low ing man ner. Apply a mini mum 19-inch-wide (483 mm) cor dance with Section 1505. Bulk shipments of mate ri als shall strip of underlayment felt paral lel with and starting at the be ac com pa nied with the same infor ma tion is sued in the form eaves, fas tened suffi ciently to hold in place. Starting at the of a cer tif i cate or on a bill of lading by the man u fac turer. eave, apply 36-inch-wide (914 mm) sheets of underlayment over lap ping suc ces sive sheets 19 inches (483 mm) and fas­ tened suffi ciently to hold in place. For roof slopes of four SECTION 1507 units ver ti cal in 12 units hor i zon tal (33-percent slope) or REQUIREMENTS FOR ROOF COVERINGS greater, underlayment shall be one layer applied in the fol ­ 1507.1 Scope. Roof cover ings shall be applied in ac cor dance low ing man ner. Underlayment shall be applied shin gle fash­ with the appli ca ble pro vi sions of this section and the man u fac­ ion, par al lel to and start ing from the eave and lapped 2 turer’s in stal la tion in struc tions. inches (51 mm), fas tened only as neces sary to hold in place. 1507.2 Asphalt shingles. The instal la tion of asphalt shingles 1507.2.8.1 High wind attach ment. Underlayment ap­ shall comply with the pro vi sions of this section and Ta ble plied in areas sub ject to high winds (greater than 110 1507.2. mph in ac cor dance with Figure 1609) shall be applied

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TABLE 1507.2 ASPHALT SHINGLE APPLICATION

COMPONENT INSTALLATION REQUIREMENT

1. Roof slope Asphalt shingles shall only be used on roof slopes of two units vertical in 12 units horizontal (2:12) or greater. For roof slopes from two units vertical in 12 units horizontal (2:12) up to four units vertical in 12 units horizontal (4:12), double underlayment application is required in accordance with Section 1507.2.8.

2. Deck requirement Asphalt shingles shall be fastened to solidly sheathed roofs.

3. Underlayment Underlayment shall conform with ASTM D 226, Type 1, or ASTM D 4869, Type 1.

For roof slopes from two units vertical in 12 units Underlayment shall be two layers applied in the following manner. Apply a horizontal (2:12), up to four units vertical in 12 units minimum 19-inch strip or underlayment felt parallel to and starting at the eaves, horizontal (4:12) fastened sufficiently to hold in place. Starting at the eave, apply 35-inch-wide sheets of underlayment overlapping successive sheets 19 inches and fastened sufficiently to hold in place.

For roof slopes from four units vertical in 12 units Underlayment shall be one layer applied in the following manner. Underlayment horizontal (4:12) or greater shall be applied shingle fashion, parallel to and starting from the eave and lapped 2 inches, fastened only as necessary to hold in place.

In ar eas where the av er age daily tem per a ture in Jan u ary A membrane that consists of at least two layers of underlayment cemented is 25�F or less or where there is a possi bil ity of ice together or of a self-adhering polymer-modified bitumen sheet shall be used in form ing along the eaves caus ing a backup of water lieu of normal underlayment and extend from the eave’s edge to a point at least 24 inches inside the exterior wall line of the building.

4. Application —

Attach ment Asphalt shingles shall have the minimum number of fasteners required by the manufacturer and Section 1504.1. Asphalt shingles shall be secured to the roof with not less than four fasteners per strip shingle or two fasteners per individual shingle. Where the roof slope exceeds 20 units vertical in 12 units horizontal (20:12), special methods of fastening are required.

Fasteners Galvanized, stainless steel, aluminum or copper roofing nails, minimum 12-gage 3 (0.015 inch) shank with a minimum /8-inch diameter head. Fasteners shall be 3 long enough to penetrate into the sheathing /4 inch or through the thickness of the sheathing.

Flashings In accordance with Section 1507.2.9.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, °C = [(°F) - 32]/1.8, 1 mile per hour = 1.609 km/h.

with corro sion- re sis tant fas ten ers in ac cor dance with the 1507.2.9.1 Base and cap flash ing. Base and cap flashing man u fac turer’s in struc tions. Fasteners are to be ap plied shall be in stalled in ac cor dance with the man u fac turer’s along the overlap at a maxi mum spac ing of 36 inches instruc tions. Base flashing shall be of either corro ­ (914 mm) on cen ter. sion-re sis tant metal of mini mum nom i nal 0.019-inch (0.483 mm) thickness or mineral-sur faced roll roof ing 1507.2.8.2 Ice dam mem brane. In ar eas where the aver ­ weighing a mini mum of 77 pounds per 100 square feet age daily tem per a ture in Jan u ary is 25°F (-4°C) or less or (3.76 kg/m2). Cap flash ing shall be cor ro sion-re sis tant where there is a possi bil ity of ice forming along the eaves metal of min i mum nomi nal 0.019-inch (0.483 mm) caus ing a backup of wate r, a membrane that consists of at thickness. least two lay ers of underlayment cemented together or of a self-adher ing poly mer modi fied bi tu men sheet shall be 1507.2.9.2 Valleys. Valley linings shall be in stalled in ac­ used in lieu of normal underlayment and extend from the cor dance with the man u fac turer’s in struc tions before ap­ eave’s edge to a point at least 24 inches (610 mm) in side ply ing shingles. Val ley linings of the follow ing types the ex te rior wall line of the build ing. shall be per mit ted: Excep tion: De tached ac ces sory struc tures that con­ 1. For open valleys (val ley lin ing exposed) lined with tain no con di tioned floor area. metal, the val ley lin ing shall be at least 16 inches 1507.2.9 Flash ings. Flashing for asphalt shingles shall (406 mm) wide and of any of the corro sion-re sis ­ com ply with this section. Flashing shall be applied in ac cor- tant metals in Table 1507.2.9.2. dance with this sec tion and the as phalt shingle man u fac­ 2. For open val leys, val ley lin ing of two plies of min­ turer’s printed in struc tions. eral-sur faced roll roofing shall be per mit ted. The

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bot tom layer shall be 18 inches (457 mm) and the slope), underlayment shall be a mini mum of two lay ers top layer a mini mum of 36 inches (914 mm) wide. applied as follows: 3. For closed valleys (valleys covered with shin gles), 1. Starting at the eave, a 19-inch (483 mm) strip of val ley lining of one ply of smooth roll roofing com­ underlayment shall be applied par al lel with the ply ing with ASTM D 224 and at least 36 inches eave and fastened suffi ciently in place. (914 mm) wide or types as described in Items 1 and 2. Starting at the eave, 36-inch-wide (914 mm) strips 2 above shall be permit ted. Specialty of underlayment felt shall be applied overlap ping underlayment shall comply with ASTM D 1970. suc ces sive sheets 19 inches (483 mm) and fastened suffi ciently in place. TABLE 1507.2.9.2 VALLEY LINING MATERIAL 1507.3.3.2 High-slope roofs. For roof slopes of four MINIMUM units ver ti cal in 12 units hor i zon tal (33-percent slope) or MATERIAL THICKNESS GAGE WEIGHT greater, underlayment shall be a mini mum of one layer of Copper — — 16 oz underlayment felt applied shingle fashion, par al lel to, and starting from the eaves and lapped 2 inches (51 mm), Aluminum 0.024 in. — — fas tened only as neces sary to hold in place. Stainless steel — 28 — 1507.3.4 Clay tile. Clay roof tile shall comply with ASTM Galvanized steel 0.0179 in. 26 (zinc-coated G90) — C 1167. Zinc alloy 0.027 in. — — 1507.3.5 Concrete tile. Concrete roof tiles shall be in accor - Lead — — 2.5 pounds dance with the physi cal test require ments as fol lows: Painted terne — — 20 pounds 1. The trans verse strength of tiles shall be deter mined For SI: 1 inch = 25.4 mm, 1 pound = 0.454 kg, 1 ounce = 28.35 g. ac cord ing to Sec tion 6.3 of ASTM C 1167 and in ac­ 1507.2.9.3 Drip edge. Provide drip edge at eaves and ga­ cor dance with Table 1507.3.5. bles of shin gle roofs. Overlap to be a mini mum of 2 2. The ab sorp tion of concrete roof tiles shall be ac cord­ inches (51 mm). Eave drip edges shall extend 0.25 inch ing to Sec tion 8 of ASTM C 140. Roof tiles shall ab­ (6.4 mm) below sheath ing and extend back on the roof a sorb not more than 15 percent of the dry weight of the min i mum of 2 inches (51 mm). Drip edge shall be me­ tile during a 24-hour im mer sion test. chan i cally fas tened a maxi mum of 12 inches (305 mm) 3. Roof tiles shall be tested for freeze/thaw re sis tance o.c. A cricket or sad dle shall be installed on the ridge side ac cord ing to Sec tion 8 of ASTM C67. Roof tiles shall of any chimney greater than 30 inches (762 mm) wide. show no break age and not have more than 1 per cent Cricket or sad dle cov er ings shall be sheet metal or of the loss in dry weight of any indi vid ual con crete roof tile. same mate rial as the roof cov er ing. TABLE 1507.3.5 1507.3 Clay and con crete tile. The instal la tion of clay and TRANSVERSE BREAKING STRENGTH con crete tile shall comply with the pro vi sions of this sec tion. OF CONCRETE ROOF TILE (lbs.) DRY 1507.3.1 Deck require ments. Con crete and clay tile shall TILE PROFILE Average of five tiles Individual tile be in stalled only over solid sheathing or spaced struc tural sheathing boards. High profile 400 350 Medium profile 300 250 1507.3.2 Deck slope. Clay and concrete roof tile shall be in­ 1 Flat profile 300 250 stalled on roof slopes of 2 /2 units verti cal in 12 units hori ­ zon tal (21-per cent slope) or greater. For roof slopes from For SI: 1 pound = 4.45 N. 1 2 /2 units ver ti cal in 12 units hori zon tal (21-percent slope) to four units ver ti cal in 12 units hori zon tal (33-per cent slope), 1507.3.6 Fasteners. Tile fasten ers shall be corro sion resis ­ 5 dou ble underlayment ap pli ca tion is required in accor dance tant and not less than 11 gage, /16-inch (8.0 mm) head, and with Section 1507.3.3. of suffi cient length to pen e trate the deck a mini mum of 0.75 inch (19.1 mm) or through the thickness of the deck, which­ 1507.3.3 Underlayment. Un less oth er wise noted, required ever is less. Attaching wire for clay or con crete tile shall not underlayment shall con form to: ASTM D 226, Type II; be smaller than 0.083 inch (2.1 mm). Per im e ter fasten ing ar­ ASTM D 2626 or ASTM D 249 Type I min eral-sur faced roll eas in clude three tile courses but not less than 36 inches (914 roof ing. mm) from ei ther side of hips or ridges and edges of eaves and gable rakes. 1 1507.3.3.1 Low-slope roofs. For roof slopes from 2 /2 units ver ti cal in 12 units hor i zon tal (21-percent slope), up 1507.3.7 Attach ment. Clay and concrete roof tiles shall be to four units ver ti cal in 12 units hor i zon tal (33-per cent fas tened in accor dance with Table 1507.3.7.

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TABLE 1507.3.7 CLAY AND CONCRETE TILE ATTACHMENTa, b, c GENERAL — CLAY OR CONCRETE ROOF TILE Maximum basic Mean roof wind speed height (mph) (feet) Roof slope up to < 3:12 Roof slope 3:12 and over 85 0-60 One fastener per tile. Flat tile Two fasteners per tile. Only one fastener on slopes of 7:12 and without vertical laps, two less for tiles with installed weight exceeding 7.5 lbs./sq. ft. 100 0-40 fasteners per tile. having a width no greater than 16 inches. The head of all tiles shall be nailed. The nose of all eave tiles shall be fastened with approved 100 > 40-60 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 1609.7.2. 120 0-60 The fastening system shall resist the wind forces in Section 1609.7.2. 130 0-60 The fastening system shall resist the wind forces in Section 1609.7.2. All > 60 The fastening system shall resist the wind forces in Section 1609.7.2. INTERLOCKING CLAY OR CONCRETE ROOF TILE WITH PROJECTING ANCHOR LUGSd, e (Installations on spaced/solid sheathing with battens or spaced sheathing) Maximum basic Mean roof wind speed height (mph) (feet) Roof slope up to < 5:12 Roof slope 5:12 < 12:12 Roof slope 12:12 and over One fastener per tile every other One fastener required for every 85 0-60 Fasteners are not required. Tiles row. All perimeter tiles require tile. Tiles with installed weight with installed weight less than 9 one fastener. Tiles with installed less than 9 lbs./sq. ft. require a lbs./sq. ft. require a minimum of weight less than 9 lbs./sq. ft. minimum of one fastener per one fastener per tile. require a minimum of one fastener 100 0-40 tile. per tile. The head of all tiles shall be nailed. The nose of all eave tiles shall be fastened with approved 100 > 40-60 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 1609.7.2. 120 0-60 The fastening system shall resist the wind forces in Section 1609.7.2. 130 0-60 The fastening system shall resist the wind forces in Section 1609.7.2. All > 60 The fastening system shall resist the wind forces in Section 1609.7.2. INTERLOCKING CLAY OR CONCRETE ROOF TILE WITH PROJECTING ANCHOR LUGS (Installations on solid sheathing without battens) Maximum basic Mean roof wind speed height (mph) (feet) All roof slopes 85 0-60 One fastener per tile. 100 0-40 One fastener per tile. The head of all tiles shall be nailed. The nose of all eave tiles shall be fastened with approved 100 > 40-60 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 1609.7.2. 120 0-60 The fastening system shall resist the wind forces in Section 1609.7.2. 130 0-60 The fastening system shall resist the wind forces in Section 1609.7.2. All > 60 The fastening system shall resist the wind forces in Section 1609.7.2. For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 1.609 km/h, 1 pound per square foot = 0.0478 kn/m2. 5 a. Mini mum fastener size. Cor ro sion-re sis tant nails not less than No. 11 gage with /16-inch head. Fasteners shall be long enough to pen e trate into the sheathing 0.75 inch or through the thickness of the sheathing, which ever is less. Attaching wire for clay and con crete tile shall not be smaller than 0.083 inch. b. Snow areas. A mini mum of two fasten ers per tile are required or battens and one fastene r. c. Roof slopes greater than 24:12. The nose of all tiles shall be securely fas tened. 1 d. Hor i zon tal battens. Battens shall be not less than 1inch by 2 inch nomi nal. Provi sions shall be made for drain age by a min i mum of /8-inch riser at each nail or by 4-foot-long battens with at least a 0.5-inch sep a ra tion between battens. Hori zon tal batte ns are required for slopes over 7:12. e. Per im e ter fasten ing ar eas in clude three tile courses but not less than 36 inches from eithe r side of hips or ridges and edges of eaves and gable rakes.

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1507.3.8 Application. Tile shall be applied according to the 3. Stainless-steel fasteners are acceptable for all types of manufacturer’s installation instructions, based on the fol­ metal roofs. lowing: TABLE 1507.4.3 1. Climatic conditions. METAL ROOF COVERINGS 2. Roof slope. STANDARD APPLICATION 3. Underlayment system. ROOF COVERING TYPE RATE/THICKNESS 4. Type of tile being installed. ASTM B 209, 0.024 inch minimum thickness for roll-formed panels and 0.019 Aluminum 1507.3.9 Flashing. At the juncture of the roof vertical sur­ inch minimum thickness for press-formed faces, flashing and counterflashing shall be provided in ac­ shingles. cordance with the manufacturer’s installation instructions, Aluminum-zinc alloy ASTM A 792 AZ 50 and where of metal, shall not be less than 0.019-inch (0.48 coated steel mm) (No. 26 galvanized sheet gage) corrosion-resistant. The valley flashing shall extend at least 11 inches (279 mm) 16 oz./sq. ft. for metal-sheet roof-covering Copper systems; 12 oz./sq. ft. for preformed metal from the centerline each way and have a splash diverter rib shingle systems. not less than 1 inch (25 mm) high at the flow line formed as ASTM A 653 G-90 zinc-coated, part of the flashing. Sections of flashing shall have an end Galvanized steel lap of not less than 4 inches (102 mm). For roof slopes of 0.013-inch-thick minimum three units vertical in 12 units horizontal (25-percent slope) Lead-coated copper ASTM B 101 and over, the valley flashing shall have a 36-inch-wide (914 Hard lead 2 lbs./sq. ft. mm) underlayment of one layer of Type I underlayment run­ ning the full length of the valley, in addition to other required Soft lead 3 lbs./sq. ft. underlayment. In areas where the average daily temperature Prepainted steel ASTM A 755 in January is 25°F (-4°C) or less or where there is a possibil­ Terne coating of 40 lbs. per double base ity of ice forming along the eaves causing a backup of water, Terne (tin) and terne- box, field painted where applicable in the metal valley flashing underlayment shall be solid ce­ coated stainless accordance with manufacturer’s mented to the roofing underlayment for slopes under seven installation instructions. units vertical in 12 units horizontal (58-percent slope) or of 2 self-adhering polymer modified bitumen sheet. For SI: 1 ounce per square foot = 0.0026 kg/m , 1 pound per square foot = 4.882 kg/m2, 1507.4 Metal roof panels. The installation of metal roof panels 1 inch = 25.4 mm, 1 pound = 0.454 kg. shall comply with the provisions of this section. 1507.5 Metal roof shingles. The installation of metal roof shingles shall comply with the provisions of this section. 1507.4.1 Deck requirements. Metal roof panel roof cover­ ings shall be applied to a solid or closely fitted deck, except 1507.5.1 Deck requirements. Metal roof shingles shall be where the roof covering is specifically designed to be ap­ applied to a solid or closely fitted deck, except where the plied to spaced supports. roof covering is specifically designed to be applied to spaced sheathing. 1507.4.2 Deck slope. The minimum slope for lapped, nonsoldered seam metal roofs without applied lap sealant 1507.5.2 Deck slope. Metal roof shingles shall not be in­ shall be three units vertical in 12 units horizontal (25-percent stalled on roof slopes below three units vertical in 12 units slope). The minimum slope for lapped, nonsoldered seam horizontal (25-percent slope). metal roofs with applied lap sealant shall be one-half vertical 1507.5.3 Underlayment. Underlayment shall conform to unit in 12 units horizontal (4-percent slope). The minimum ASTM D 226, Type I. In areas where the average daily tem­ slope for standing seam of roof systems shall be one-quarter perature in January is 25°F (-4°C) or less or where there is a unit vertical in 12 units horizontal (2-percent slope). possibility of ice forming along the eaves causing a backup 1507.4.3 Material standards. Metal-sheet roof covering of water, an ice barrier that consists of at least two layers of systems that incorporate supporting structural members underlayment cemented together or of a self-adhering poly­ shall be designed in accordance with Chapter 22. mer-modified bitumen sheet, shall be used in lieu of normal Metal-sheet roof coverings installed over structural decking underlayment and extend from the eave’s edge to a point at shall comply with Table 1507.4.3. least 24 inches (610 mm) inside the exterior wall line of the building. 1507.4.4 Attachment. Metal roofing fastened directly to steel framing shall be attached by approved manufacturers’ Exception: Detached accessory structures that contain fasteners. In the absence of manufacturer recommenda­ no conditioned floor area. tions, all of the following fasteners shall be used: 1507.5.4 Material standards. Metal roof shingle roof cov­ 1. Galvanized fasteners shall be used for galvanized erings shall comply with Table 1507.4.3. roofs. 1507.5.5 Attachment. Metal roof shingles shall be secured 2. 300 series stainless-steel fasteners shall be used for to the roof in accordance with the approved manufacturer’s copper roofs. installation instructions.

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1507.5.6 Flashing. Roof val ley flashing shall be of cor ro­ Ex cep tion: De tached ac ces sory struc tures that con tain sion-re sis tant metal of the same mate rial as the roof cover ­ no con di tioned floor area. ing or shall com ply with the standards in Table 1507.4.3. The valley flashing shall extend at least 8 inches (203 mm) 1507.7.4 Ma te rial standards. Slate shin gles shall comply from the cen ter line each way and shall have a splash di verter with ASTM C 406. rib not less than 0.75 inch (19.1 mm) high at the flow line 1507.7.5 Ap pli ca tion. Mini mum headlap for slate shingles formed as part of the flash ing. Sec tions of flash ing shall shall be in accor dance with Table 1507.7.5. Slate shin gles have an end lap of not less than 4 inches (102 mm). In ar eas shall be secured to the roof with two fasten ers per slate. where the av er age daily tem per a ture in Jan u ary is 25°F TABLE 1507.7.5 (-4°C) or less or where there is a possi bil ity of ice form ing SLATE SHINGLE HEADLAP along the eaves caus ing a backup of wa ter, the metal val ley flashing shall have a 36-inch-wide (914 mm) underlayment HEADLAP SLOPE (inches) directly under it con sist ing of one layer of underlayment run ning the full length of the val ley, in ad di tion to 4:12 < slope < 8:12 4 underlayment re quired for metal roof shingles. The metal 8:12 < slope < 20:12 3 val ley flash ing underlayment shall be solid cemented to the roofing underlayment for roof slopes un der seven units ver­ slope ‡ 20:12 2 ti cal in 12 units hor i zon tal (58-percent slope) or of self-ad­ For SI: 1 inch = 25.4 mm. hering poly mer-mod i fied bi tu men sheet. 1507.6 Min eral-sur faced roll roofing. The instal la tion of 1507.7.6 Flashing. Flashing and counterflashing shall be min eral-sur faced roll roofing shall com ply with this section. made with sheet metal. Val ley flash ing shall be a min i mum of 15 inches (381 mm) wide. Val ley and flashing metal shall 1507.6.1 Deck re quire ments. Min eral-sur faced roll roof­ be a mini mum uncoat ed thickness of 0.0179-inch (0.455 ing shall be fas tened to sol idly sheathed roofs. mm) zinc-coated G90. Chimneys, stucco or brick walls shall 1507.6.2 Deck slope. Mineral-sur faced roll roofing shall have a mini mum of two plies of felt for a cap flashing con ­ not be applied on roof slopes be low one unit ver ti cal in 12 sisting of a 4-inch-wide (102 mm) strip of felt set in plas tic units hori zon tal (8-percent slope). ce ment and ex tend ing 1 inch (25 mm) above the first felt and 1507.6.3 Underlayment. Underlayment shall con form to a top coating of plas tic cement. The felt shall extend over the ASTM D 226, Type I. In areas where the av er age daily tem­ base flashing 2 inches (51 mm). per a ture in Janu ary is 25°F (-4°C) or less or where there is a 1507.8 Wood shin gles. The instal la tion of wood shin gles shall pos si bil ity of ice forming along the eaves causing a backup com ply with the pro vi sions of this section and Ta ble 1507.8. of water, an ice bar rier that con sists of at least two layers of underlayment cemented together or of a self-ad her ing poly­ 1507.8.1 Deck re quire ments. Wood shin gles shall be in­ mer-modi fied bi tu men sheet, shall extend from the eave’s stalled on solid or spaced sheathing. Where spaced sheath ­ edge to a point at least 24 inches (610 mm) in side the ex te­ ing is used, sheathing boards shall not be less than 1-inch by rior wall line of the building. 4-inch (25 mm by 102 mm) nomi nal di men sions and shall be spaced on centers equal to the weather expo sure to co in­ Excep tion: De tached ac ces sory structures that con tain cide with the placement of fasten ers. no con di tioned floor area. 1507.6.4 Ma te rial standards. Min eral-sur faced roll roof ­ 1507.8.1.1 Solid sheathing required. Solid sheathing is ing shall con form to ASTM D 224, ASTM D 249, ASTM D re quired in ar eas where the av er age daily tem per a ture in 371 or ASTM D 3909. Jan u ary is 25°F (-4°C) or less or where there is a pos si bil­ ity of ice forming along the eaves causing a backup of 1507.7 Slate shin gles. The in stal la tion of slate shingles shall wa ter. com ply with the pro vi sions of this sec tion. 1507.7.1 Deck re quire ments. Slate shin gles shall be fas­ 1507.8.2 Deck slope. Wood shin gles shall be installed on slopes of three units ver ti cal in 12 units hori zon tal (25-per ­ tened to sol idly sheathed roofs. cent slope) or greater. 1507.7.2 Deck slope. Slate shin gles shall only be used on slopes of four units ver ti cal in 12 units hor i zon tal (4:12) or 1507.8.3 Underlayment. Underlayment shall com ply with greater. ASTM D 226, Type I. In areas where the av er age daily tem­ per a ture in Jan u ary is 25°F (-4°C) or less or where there is a 1507.7.3 Underlayment. Underlayment shall com ply with possi bil ity of ice forming along the eaves causing a backup ASTM D 226, Type II. In areas where the av er age daily tem­ of water, an ice bar rier that con sists of at least two lay ers of per a ture in Janu ary is 25°F (-4°C) or less or where there is a underlayment cemented together or of a self-ad her ing poly­ pos si bil ity of ice forming along the eaves causing a backup mer-modi fied bitu men sheet shall extend from the eave’s of water, an ice bar rier that con sists of at least two layers of edge to a point at least 24 inches (610 mm) in side the exte ­ underlayment cemented together or of a self-ad her ing poly­ rior wall line of the building. mer-modi fied bi tu men sheet, shall extend from the eave’s edge to a point at least 24 inches (610 mm) in side the ex te­ Ex cep tion: De tached ac ces sory struc tures that con tain rior wall line of the building. no con di tioned floor area.

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TABLE 1507.8 WOOD SHINGLE AND SHAKE INSTALLATION ROOF ITEM WOOD SHINGLES WOOD SHAKES Wood shingles shall be installed on slopes of Wood shakes shall be installed on slopes of four units 1. Roof slope three units vertical in 12 units horizontal (3:12) vertical in 12 units horizontal (4:12) or greater. or greater. 2. Deck requirement — — Temperate climate Shingles shall be applied to roofs with solid or Shakes shall be applied to roofs with solid or spaced spaced sheathing. Where spaced sheathing is sheathing.Where spaced sheathing is used, sheathing used, sheathing boards shall not be 4 less than boards shall not be less than 1† × 4† nominal dimensions 1† × 4† nominal dimensions and shall be and shall be spaced on center equal to the weather spaced on center equal to the weather exposure exposure to coincide with the placement of fasteners. 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.

In areas where the average daily Solid sheathing required. Solid sheathing is required. temperature in January is 25�F or less or where there is a possibility of ice forming along the eaves causing a backup of water. Interlayment shall comply with ASTM D 226, Type 3. Interlayment No requirements. 1. 4. Underlayment — — Temperate climate Underlayment shall comply with ASTM D Underlayment shall com ply with ASTM D 226, Type 1. 226, Type 1. In areas where the average daily An ice shield that consists of at least two layers An ice shield that consists of at least two layers of temperature in January is 25�F of underlayment cemented together or of a underlayment cemented together or of a self-adhering or less or where there is a self-adhering polymer-modified bitumen sheet polymer-modified bitumen sheet shall extend from the possibility of ice forming along shall extend from the eave’s edge to a point at eave’s edge to a point at least 24 inches inside the the eaves causing a backup of least 24 inches inside the exterior wall line of exterior wall line of the building. water. the building. 5. Application — — Attachment Fasteners for wood shingles shall be corrosion Fasteners for wood shakes shall be corrosion resistant resistant with a minimum penetration of 0.75 with a minimum penetration of 0.75 inch into the inch into the sheathing. For sheathing less than sheathing. For sheathing less than 0.5 inch thick, the 0.5 inch thick, the fasteners shall extend fasteners shall extend through the sheathing. through the sheathing. No. of fasteners Two per shingle. Two per shake. Exposure Weather exposures shall not exceed those set Weather exposures shall not exceed those set forth in forth in Table 1507.8.6 Table 1507.9.7 Method Shingles shall be laid with a side lap of not less Shakes shall be laid with a side lap of not less than 1.5 than 1.5 inches between joints in courses, and no inches between joints in adjacent courses. Spacing two joints in any three adjacent courses shall be between shakes shall not be less than 0.375 inch or in direct alignment. Spacing between shingles more than 0.625 inch for shakes and tapersawn shakes shall be 0.25 to 0.375 inch. of naturally durable wood and shall be 0.25 to 0.375 inch for preservative taper sawn shakes. Flashing In accordance with Section 1507.8.7. In accordance with Section 1507.9.8. For SI: 1 inch = 25.4 mm, °C = [(°F) - 32]/1.8.

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1507.8.4 Material standards. Wood shingles shall be of 1507.9 Wood shakes. The installation of wood shakes shall naturally durable wood and comply with the requirements comply with the provisions of this section and Table 1507.8. of Table 1507.8.4. 1507.9.1 Deck requirements. Wood shakes shall only be TABLE 1507.8.4 used on solid or spaced sheathing. Where spaced sheathing WOOD SHINGLE MATERIAL REQUIREMENTS is used, sheathing boards shall not be less than 1-inch by APPLICABLE 4-inch (25 mm by 102 mm) nominal dimensions and shall MATERIAL MINIMUM GRADES GRADING RULES be spaced on centers equal to the weather exposure to coin­ Wood shingles of naturally 1, 2 or 3 CSSB cide with the placement of fasteners. Where 1-inch by durable wood 4-inch (25 mm by 102 mm) spaced sheathing is installed at CSSB = Cedar Shake and Shingle Bureau 10 inches (254 mm) o.c., additional 1-inch by 4-inch (25 1507.8.5 Attachment. Fasteners for wood shingles shall be mm by 102 mm) boards shall be installed between the corrosion resistant with a minimum penetration of 0.75 inch sheathing boards. (19.1 mm) into the sheathing. For sheathing less than 0.5 1507.9.1.1 Solid sheathing required. Solid sheathing is inch (12.7 mm) in thickness, the fasteners shall extend required in areas where the average daily temperature in through the sheathing. Each shingle shall be attached with a January is 25°F (-4°C) or less or where there is a possibil­ minimum of two fasteners. ity of ice forming along the eaves causing a backup of 1507.8.6 Application. Wood shingles shall be laid with a water. side lap not less than 1.5 inches (38 mm) between joints in 1507.9.2 Deck slope. Wood shakes shall only be used on adjacent courses, and not be in direct alignment in alternate slopes of four units vertical in 12 units horizontal (33-per­ courses. Spacing between shingles shall be 0.25 to 0.375 cent slope) or greater. inches (6.4 to 9.5 mm). Weather exposure for wood shingles 1507.9.3 Underlayment. Underlayment shall comply shall not exceed that set in Table 1507.8.6. with ASTM D 226, Type I. In areas where the average daily TABLE 1507.8.6 temperature in January is 25°F (-4°C) or less or where WOOD SHINGLE WEATHER EXPOSURE AND ROOF SLOPE there is a possibility of ice forming along the eaves causing EXPOSURE (inches) a backup of water, an ice barrier that consists of at least two LENGTH 3:12 pitch 4:12 pitch layers of underlayment cemented together or a self-adher­ ROOFING MATERIAL (inches) GRADE to < 4:12 or steeper ing polymer-modified bitumen sheet shall extend from the No. 1 3.75 5 edge of the eave to a point at least 24 inches (610 mm) in­ 16 No. 2 3.5 4 side the exterior wall line of the building. No. 3 3 3.5 Exception: Detached accessory structures that contain No. 1 4.25 5.5 Shingles of naturally no conditioned floor area. 18 No. 2 4 4.5 durable wood No. 3 3.5 4 1507.9.4 Interlayment. Interlayment shall comply with ASTM D 226, Type I. No. 1 5.75 7.5 24 No. 2 5.5 6.5 1507.9.5 Material standards. Wood shakes shall comply No. 3 5 5.5 with the requirements of Table 1507.9.5. For SI: 1 inch = 25.4 mm. TABLE 1507.9.5 WOOD SHAKE MATERIAL REQUIREMENTS 1507.8.7 Flashing. At the juncture of the roof and vertical APPLICABLE surfaces, flashing and counterflashing shall be provided in MINIMUM GRADING accordance with the manufacturer’s installation instruc­ MATERIAL GRADES RULES tions, and where of metal, shall not be less than 0.019-inch Wood shakes of naturally durable wood 1 CSSB (0.48 mm) (No. 26 galvanized sheet gage) corrosion-resis­ Taper sawn shakes of naturally durable tant metal. The valley flashing shall extend at least 11 inches 1 or 2 CSSB (279 mm) from the centerline each way and have a splash di­ wood verter rib not less than 1 inch (25 mm) high at the flow line Preservative-treated shakes and 1 CSSB formed as part of the flashing. Sections of flashing shall shingles of naturally durable wood have an end lap of not less than 4 inches (102 mm). For roof Fire-retardant-treated shakes and 1 CSSB slopes of three units vertical in 12 units horizontal (25-per­ shingles of naturally durable wood cent slope) and over, the valley flashing shall have a 36-inch-wide (914 mm) underlayment of one layer of Type I Preservative-treated taper sawn shakes underlayment running the full length of the valley, in addi­ of Southern yellow pine treated in 1 or 2 TFS accordance with AWPA Standard C2 tion to other required underlayment. In areas where the av­ erage daily temperature in January is 25°F (-4°C) or less or CSSB = Cedar Shake and Shingle Bureau. where there is a possibility of ice forming along the eaves TFS = Forest Products Laboratory of the Texas Forest Services. causing a backup of water, the metal valley flashing 1507.9.6 Attachment. Fasteners for wood shakes shall be underlayment shall be solid cemented to the roofing corrosion resistant with a minimum penetration of 0.75 inch underlayment for slopes under seven units vertical in 12 (19.1 mm) into the sheathing. For sheathing less than 0.5 units horizontal (58-percent slope). inch (12.7 mm) in thickness, the fasteners shall extend

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through the sheathing. Each shake shall be attached with a 1507.10.2 Material standards. Built-up roof covering ma­ minimum of two fasteners. terials shall comply with the standards in Table 1507.10.2. 1507.9.7 Application. Wood shakes shall be laid with a side 1507.11 Modified bitumen roofing. The installation of modi­ lap not less than 1.5 inches (38 mm) between joints in adja­ fied bitumen roofing shall comply with the provisions of this cent courses. Spacing between shakes in the same course section. shall be 0.375 to 0.625 inches (9.5 to 15.9 mm) for shakes and taper sawn shakes of naturally durable wood and shall TABLE 1507.10.2 be 0.25 to 0.375 inch (6.4 to 9.5 mm) for preservative taper BUILT-UP ROOFING MATERIAL STANDARDS sawn shakes. Weather exposure for wood shakes shall not MATERIAL STANDARD STANDARD exceed those set in Table 1507.9.7. Acrylic coatings used in roofing ASTM D 6083 TABLE 1507.9.7 WOOD SHAKE WEATHER EXPOSURE Aggregate surfacing ASTM D 1863 AND ROOF SLOPE Asphalt adhesive used in roofing ASTM D 3747 EXPOSURE ASTM D 3019; D 2822; (inches) Asphalt cements used in roofing LENGTH 4:12 PITCH D 4586 ROOFING MATERIAL (inches) GRADE OR STEEPER Asphalt-coated glass fiber base sheet ASTM D 4601 Shakes of naturally 18 No. 1 7.5 ASTM D1227; D 2823; D durable wood 24 No. 1 10a Asphalt coatings used in roofing 4479 18 No. 1 7.5 Preservative-treated taper 24 No. 1 10 Asphalt glass felt ASTM D 2178 sawn shakes of Southern Asphalt primer used in roofing ASTM D 41 yellow pine 18 No. 2 5.5 24 No. 2 7.5 Asphalt-saturated and asphalt-coated ASTM D 2626 18 No. 1 7.5 organic felt base sheet Taper sawn shakes of 24 No. 1 10 Asphalt-saturated organic felt ASTM D 226 naturally durable wood 18 No. 2 5.5 (perforated) 24 No. 2 7.5 Asphalt used in roofing ASTM D 312 For SI: 1 inch = 25.4 mm. Coal-tar cements used in roofing ASTM D 4022; D 5643 a. For 24-inch by 0.375-inch handsplit shakes, the maximum exposure is 7.5 inches. Coal-tar saturated organic felt ASTM D 227 1507.9.8 Flashing. At the juncture of the roof and vertical Coal-tar pitch used in roofing ASTM D 450; Type I or II surfaces, flashing and counterflashing shall be provided in Coal-tar primer used in roofing, accordance with the manufacturer’s installation instruc­ ASTM D 43 tions, and where of metal, shall not be less than 0.019-inch damproofing and waterproofing (0.48 mm) (No. 26 galvanized sheet gage) corrosion-resis­ Glass mat, coal tar ASTM D 4990 tant metal. The valley flashing shall extend at least 11 inches (279 mm) from the centerline each way and have a splash di­ Glass mat, venting type ASTM D 4897 verter rib not less than 1 inch (25 mm) high at the flow line Mineral-surfaced inorganic cap sheet ASTM D 3909 formed as part of the flashing. Sections of flashing shall have an end lap of not less than 4 inches (102 mm). For roof Thermoplastic fabrics used in roofing ASTM D 5665, D 5726 slopes of 3 units vertical in 12 units horizontal (25-percent 1507.11.1 Slope. Modified bitumen membrane roofs shall slope) and over, the valley flashing shall have a have a design slope of a minimum of one-fourth unit vertical 36-inch-wide (914 mm) underlayment of one layer of Type I in 12 units horizontal (2-percent slope) for drainage. underlayment running the full length of the valley, in addi­ tion to other required underlayment. In areas where the aver­ 1507.11.2 Material standards. Modified bitumen roof age daily temperature in January is 25°F (-4°C) or less or coverings shall comply with CGSB 37-GP-56M, ASTM D where there is a possibility of ice forming along the eaves 6162, ASTM D 6163, ASTM D 6164, ASTM D 6222, causing a backup of water, the metal valley flashing ASTM D 6223 and ASTM D 6298. underlayment shall be solid cemented to the roofing 1507.12 Thermoset single-ply roofing. The installation of underlayment for slopes under seven units vertical in 12 thermoset single-ply roofing shall comply with the provisions units horizontal (58-percent slope). of this section. 1507.10 Built-up roofs. The installation of built-up roofs shall comply with the provisions of this section. 1507.12.1 Slope. Thermoset single-ply membrane roofs shall have a design slope of a minimum of one-fourth unit 1507.10.1 Slope. Built-up roofs shall have a design slope of vertical in 12 units horizontal (2-percent slope) for drainage. a minimum of one-fourth unit vertical in 12 units horizontal (2-percent slope) for drainage, except for coal-tar built-up 1507.12.2 Material standards. Thermoset single-ply roof roofs that shall have a design slope of a minimum one-eighth coverings shall comply with RMA RP-1, RP-2 or RP-3, or unit vertical in 12 units horizontal (1-percent slope). ASTM D 4637, ASTM D 5019 or CGSB 37-GP-52M.

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1507.13 Thermoplastic single-ply roofing. The installation ceed 28 feet (8534 mm) above the roof where used as an enclo­ of thermoplastic single-ply roofing shall comply with the pro­ sure for tanks or for elevators that run to the roof and in all other visions of this section. cases shall not extend more than 18 feet (5486 mm) above the 1507.13.1 Slope. Thermoplastic single-ply membrane roof. The aggregate area of penthouses and other rooftop struc­ roofs shall have a design slope of a minimum of one-fourth tures shall not exceed one-third the area of the supporting roof. unit vertical in 12 units horizontal (2-percent slope). A penthouse, bulkhead or any other similar projection above the roof shall not be used for purposes other than shelter of me­ 1507.13.2 Material standards. Thermoplastic single-ply chanical equipment or shelter of vertical shaft openings in the roof coverings shall comply with ASTM D 4434 or CGSB roof. Provisions such as louvers, louver blades or flashing shall 37-GP-54M. be made to protect the mechanical equipment and the building 1507.14 Sprayed polyurethane foam roofing. The installa­ interior from the elements. Penthouses or bulkheads used for tion of sprayed polyurethane foam roofing shall comply with purposes other than permitted by this section shall conform to the provisions of this section. the requirements of this code for an additional story. The re­ strictions of this section shall not prohibit the placing of wood 1507.14.1 Slope. Sprayed polyurethane foam roofs shall flagpoles or similar structures on the roof of any building. have a design slope of a minimum of one-fourth unit vertical in 12 units horizontal (2-percent slope) for drainage. 1509.2.1 Type of construction. Penthouses shall be con­ 1507.14.2 Material standards. Spray-applied polyure­ structed with walls, floors and roof as required for the build­ thane foam insulation shall comply with ASTM C 1029. ing. 1507.14.3 Application. Foamed-in-place roof insulation Exceptions: shall be installed in accordance with the manufacturer’s in­ structions. A liquid-applied protective coating that com­ 1. On buildings of Type I and II construction, the ex­ plies with Section 1507.15 shall be applied no less than 2 terior walls and roofs of penthouses with a fire sep­ hours nor more than 72 hours following the application of aration distance of more than 5 feet (1524 mm) and the foam. less than 20 feet (6096 mm) shall be of at least 1-hour fire-resistance-rated noncombustible con­ 1507.14.4 Foam plastics. Foam plastic materials and instal­ struction. Walls and roofs with a fire separation lation shall comply with Chapter 26. distance of 20 feet (6096 mm) or greater shall be of 1507.15 Liquid-applied coatings. The installation of liq­ noncombustible construction. Interior framing and uid-applied coatings shall comply with the provisions of this walls shall be of noncombustible construction. section. 2. On buildings of Type III, IV and V construction, 1507.15.1 Slope. Liquid-applied roofs shall have a design the exterior walls of penthouses with a fire separa­ slope of a minimum of one-fourth unit vertical in 12 units tion distance of more than 5 feet (1524 mm) and horizontal (2-percent slope). less than 20 feet (6096 mm) shall be at least 1-hour fire-resistance-rated construction. Walls with a fire 1507.15.2 Material standards. Liquid-applied roof coat­ separation distance of 20 feet (6096 mm) or greater ings shall comply with ASTM C 836, ASTM C 957, ASTM from a common property line shall be of Type IV or D 6083, ASTM D 1227 or ASTM D 3468. noncombustible construction. Roofs shall be con­ structed of materials and fire-resistance rated as re­ quired in Table 601. Interior framing and walls SECTION 1508 shall be Type IV or noncombustible construction. ROOF INSULATION 3. Unprotected noncombustible enclosures housing 1508.1 General. The use of above-deck thermal insulation only mechanical equipment and located with a shall be permitted provided such insulation is covered with an minimum fire separation distance of 20 feet (6096 approved roof covering and passes the tests of FM 4450 or UL mm) shall be permitted. 1256 when tested as an assembly. 4. On one-story buildings, combustible unroofed me­ Exception: Foam plastic roof insulation shall conform to chanical equipment screens, fences or similar en­ the material and installation requirements of Chapter 26. closures are permitted where located with a fire 1508.1.1 Cellulosic fiberboard. Cellulosic fiberboard roof separation distance of at least 20 feet (6096 mm) insulation shall conform to the material and installation re­ from adjacent property lines and where not ex­ quirements of Chapter 23. ceeding 4 feet (1219 mm) in height above the roof surface. 5. Dormers shall be of the same type of construction SECTION 1509 as the roof on which they are placed, or of the exte­ ROOFTOP STRUCTURES rior walls of the building. 1509.1 General. The provisions of this section shall govern the 1509.3 Tanks. Tanks having a capacity of more than 500 gal­ construction of rooftop structures. lons (2 m3) placed in or on a building shall be supported on ma­ 1509.2 Penthouses. A penthouse or other projection above the sonry, reinforced concrete, steel or Type IV construction roof in structures of other than Type I construction shall not ex­ provided that, where such supports are located in the building

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above the lowest story, the sup port shall be fire-resis tance rated SECTION 1510 as required for Type IA construc tion. REROOFING

1509.3.1 Valve. Such tanks shall have in the bottom or on 1510.1 General. Ma te rials and methods of ap pli ca tion used for the side near the bot tom, a pipe or outlet, fit ted with a suit­ re cov er ing or replac ing an exist ing roof cover ing shall comply able quick opening valve for discharg ing the con tents in an with the re quire ments of Chap ter 15. emer gency through an ad e quate drain. Excep tion: Reroofing shall not be required to meet the min­ imum de sign slope re quire ment of one-quarter unit verti cal 1509.3.2 Loca tion. Such tanks shall not be placed over or in 12 units hor i zon tal (2-per cent slope) in Section 1507 for near a line of stairs or an el e va tor shaft, un less there is a solid roofs that provide posi tive roof drainage. roof or floor un der neath the tank. 1510.2 Structural and construc tion loads. Structural roof 1509.3.3 Tank cover. Un en closed roof tanks shall have cov­ com po nents shall be ca pa ble of sup port ing the roof-cover ing ers slop ing to ward the outer edges. sys tem and the mate rial and equip ment loads that will be en ­ coun tered during instal la tion of the system. 1509.4 Cooling towers. Cooling towers in ex cess of 250 square feet (23.2 m2) in base area or in excess of 15 feet (4572 1510.3 Re covering versus replace ment. New roof cov er ings mm) high where located on buildings more than 50 feet (15 240 shall not be in stalled with out first remov ing all exist ing layers mm) high shall be of noncombustible construc tion. Cooling of roof cov er ings where any of the fol low ing condi tions oc cur: towers shall not exceed one-third of the support ing roof area. 1. Where the exist ing roof or roof cover ing is wa ter soaked or has dete ri o rated to the point that the exist ing roof or Excep tion: Drip boards and the enclos ing construc tion of roof cover ing is not ad e quate as a base for ad di tional wood not less than 1 inch (25 mm) nom i nal thick ness, pro ­ roof ing. vided the wood is cov ered on the ex te rior of the tower with noncombustible ma te rial. 2. Where the exist ing roof cover ing is wood shake, slate, clay, ce ment or asbes tos-ce ment tile. 1509.5 Towers, spires, domes and cu po las. Any tower, spire, 3. Where the exist ing roof has two or more ap pli ca tions of dome or cupola shall be of a type of construc tion not less in any type of roof cov er ing. fire-resis tance rating than required for the building to which it Excep tions: is at tached ex cept that any such tower, spire, dome or cupola that ex ceeds 85 feet (25 908 mm) in height above grade, or ex­ 1. Com plete and sep a rate roof ing systems, such as ceeds 200 square feet (18.6 m2) in hor i zon tal area or is used for stand ing-seam metal roof systems, that are de signed any pur pose other than a belfry or an ar chi tec tural embel lish ­ to trans mit the roof loads di rectly to the build ing’s ment shall be constructed of and supported on Type I or II con­ struc tural sys tem and that do not rely on exist ing roofs struction. and roof cov er ings for sup port, shall not require the removal of exist ing roof cov er ings. 1509.5.1 Noncombustible con struc tion required. Any 2. Metal panel, metal shin gle, and concrete and clay tile tower, spire, dome or cupola that exceeds 60 feet (18 288) in roof cover ings shall be per mit ted to be in stalled over height above the highest point at which it co mes in con tact ex ist ing wood shake roofs when applied in accor - with the roof, or that ex ceeds 200 square feet (18.6 m2) in dance with Sec tion 1510.4. area at any hor i zon tal section, or which is in tended to be used for any pur pose other than a belfry or ar chi tec tural em- 1510.4 Roof re cov er ing. Where the ap pli ca tion of a new roof bellish ment, shall be entirely constructed of and supported cov er ing over wood shingle or shake roofs creates a com bus ti­ by noncombustible ma te ri als. Such struc tures shall be sepa - ble con cealed space, the entire exist ing surface shall be covered rated from the build ing be low by construc tion having a with gyp sum board, mineral fi ber, glass fiber or other approved fire-resis tance rating of not less than 1.5 hours with open­ ma te ri als securely fas tened in place. ings pro tected with a mini mum 1.5-hour fire-pro tec tion rat­ ing. Struc tures, except aerial supports 12 feet (3658 mm) 1510.5 Re in stal la tion of mate ri als. Existing slate, clay or ce­ high or less, flag poles, wa ter tanks and cooling tow ers, ment tile shall be permit ted for re in stal la tion, except that dam ­ placed above the roof of any building more than 50 feet (15 aged, cracked or bro ken slate or tile shall not be rein stalled. 240 mm) in height, shall be of noncombustible mate rial and Existing vent flashing, metal edgings, drain out lets, collars and shall be sup ported by construc tion of noncombustible ma te­ metal counterflashings shall not be rein stalled where rusted, rial. dam aged or dete ri o rated. Ag gre gate surfac ing mate ri als shall not be rein stalled. 1509.5.2 Towers and spires. Towers and spires where en ­ closed shall have exte rior walls as required for the building 1510.6 Flash ings. Flashings shall be recon structed in accor - to which they are attached. The roof cover ing of spires shall dance with ap proved man u fac turer’s instal la tion in struc tions. be of a class of roof cover ing as required for the main roof of Metal flash ing to which bi tu mi nous mate ri als are to be ad hered the rest of the structure. shall be primed prior to instal la tion.

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