The following words and terms shall, for the purposes of this chapter and as used elsewhere in this code, have the meanings shown herein.
AGGREGATE. In roofing, crushed stone, crushed slag or water-worn gravel used for surfacing for roof coverings.
BALLAST. In roofing, ballast comes in the form of large stones or paver systems or light-weight interlocking paver systems and is used to provide uplift resistance for roofing systems that are not adhered or mechanically attached to the roof deck.
BUILT-UP ROOF COVERING. Two or more layers of felt cemented together and surfaced with a cap sheet, mineral aggregate, smooth coating or similar surfacing material.
METAL ROOF PANEL. An interlocking metal sheet having a minimum installed weather exposure of 3 square feet (0.279 m2) per sheet.
METAL ROOF SHINGLE. An interlocking metal sheet having an installed weather exposure less than 3 square feet (0.279 m2) per sheet.
MODIFIED BITUMEN ROOF COVERING. One or more layers of polymer-modified asphalt sheets. The sheet materials shall be fully adhered or mechanically attached to the substrate or held in place with an approved ballast layer.
PENTHOUSE. An enclosed, unoccupied structure above the roof of a building, other than a tank, tower, spire, dome cupola or bulkhead.
PHOTOVOLTAIC PANEL. A collection of modules mechanically fastened together, wired and designed to provide a field-installable unit.
POSITIVE ROOF DRAINAGE. The drainage condition in which consideration has been made for all loading deflections of the roof deck, and additional slope has been provided to ensure drainage of the roof within 48 hours of precipitation.
RADIANT BARRIER. A material having a low-emittance surface of 0.1 or less installed in building assemblies.
ROOF ASSEMBLY. A system designed to provide weather protection and resistance to design loads. The system consists of a roof covering and roof deck or a single component serving as both the roof covering and the roof deck. A roof assembly includes the roof deck, vapor retarder, substrate or thermal barrier, insulation and roof covering.
ROOF DECK. The flat or sloped surface not including its supporting members or vertical supports.
ROOF SECTION. A separation or division of a roof area by existing joints, parapet walls, flashing (excluding valleys), difference of elevation (excluding hips and ridges), roof type or legal description; not including the roof area required for a proper tie-off with an existing system.
ROOF VENTILATION. The natural or mechanical process of supplying conditioned or unconditioned air to, or removing such air from, attics, cathedral ceilings or other enclosed spaces over which a roof assembly is installed.
ROOFTOP STRUCTURE. An enclosed structure on or above the roof of any part of a building.
VEGETATIVE ROOF. An assembly of interacting components designed to waterproof and normally insulate a building's top surface that includes, by design, vegetation and related landscape elements.
Flashing shall be used to seal roofing systems, where the system is interrupted or terminated and shall be installed in such a manner so as to prevent moisture entering the wall and roof through joints in copings, through moisture-permeable materials and at intersections with parapet walls and other penetrations through the roof plane.
METAL FLASHING MATERIAL
|GAGE||WEIGHT (LBS |
PER SQ FT)
|Copper||1 (16 oz)|
|0.0179||26 (zinc |
|0.0179||26 (AZ50 |
|Lead||2.5 (40 oz)|
|Painted Terne||1.25 (20 oz)|
Flashing shall be installed at wall and roof intersections, at gutters, wherever there is a change in roof slope or direction and around roof openings. Where flashing is of metal, the metal shall be corrosion resistant with a thickness of not less than provided in Table 1503.2 or in compliance with RAS 111.
Exception: This requirement does not apply to hip and ridge junctions.
A cricket or saddle shall be installed on the ridge side of any chimney or penetration greater than 30 inches (762 mm) wide as measured perpendicular to the slope. Cricket or saddle coverings shall be sheet metal or of the same material as the roof covering.
Exception: Unit skylights installed in accordance with Section 2405.5 and flashed in accordance with the manufacturer's instructions shall be permitted to be installed without a cricket or saddle.
Exceptions: Metal roofs constructed of cold-formed steel, where the roof deck acts as the roof covering and provides both weather protection and support for structural loads, shall be permitted to be designed and tested in accordance with the applicable referenced structural design standard in Section 2210.1.
Metal roof shingles applied to a solid or closely fitted deck shall be tested in accordance with FM 4474, UL 580, UL 1897, ASTM D3161 or TAS 107. Metal roof shingles tested in accordance with ASTM D3161 shall meet the classification requirements of Table 1504.3.3 for the appropriate maximum basic wind speed and the metal shingle packaging shall bear a label to indicate compliance with ASTM D3161 and the required classification in Table 1504.3.3.
|MAXIMUM BASIC WIND SPEED FROM FIGURE 1609.3(3), FIGURE 1609.3(4) or |
|110||85||D or F|
|116||90||D or F|
|129||100||D or F|
Aggregate shall be permitted as roof surfacing when installed on slopes of 3:12 or less, not less than 400 pound (182 kg) of roofing gravel or 300 pounds (145 kg) of slag per square shall be applied. A minimum of 50 percent of the total aggregate shall be embedded in the flood coat of bitumen or installed in accordance with its product approval. Aggregate shall be dry and free from dirt and shall be in compliance with the sizing requirements set forth in ASTM D1863. A building official may request a test to confirm compliance with these requirements.
A margin of safety of 2:1 shall be applied to all wind-uplift resistance-test results except when a margin of safety is specified in the test standard.
Exception: Asphalt shingles testing resulting in a miles per hour rating as required in Section 1507.2.7.
Roof assemblies shall be divided into the classes defined below. Class A, B and C roof assemblies and roof coverings required to be listed by this section shall be tested in accordance with ASTM E108 or UL 790. In addition, fire-retardant-treated wood roof coverings shall be tested in accordance with ASTM D2898. The minimum roof coverings installed on buildings shall comply with Table 1505.1 based on the type of construction of the building.
Class A roof assemblies are those that are effective against severe fire test exposure. Class A roof assemblies and roof coverings shall be listed and identified as Class A by an approved testing agency. Class A roof assemblies shall be permitted for use in buildings or structures of all types of construction.
Underlayment for roof slopes 2:12 and greater shall conform to the applicable standards listed in this chapter. Underlayment materials required to comply with ASTM D226, D1970, D4869 and D6757 shall bear a label indicating compliance to the standard designation and, if applicable, type classification indicated. Underlayment for roof slopes 2:12 and greater shall be applied and attached in accordance with Section 1507.1.1.1, 1507.1.1.2 or 1507.1.1.3 as applicable.
|Roof Covering||Underlayment |
|Roof Slope 2:12 and Less Than |
|Roof Slope 4:12 and Greater|
|Asphalt Shingles, |
Metal RoofPanels, Photovoltaic
|ASTM D226 |
Type IIASTM D4869
Type IIIor IV
ASTM D 6757
Apply in accordancewith Section 1507.1.1.1,
Item 4 orSection 1507.1.1.3,
Item 3 as applicableto the type of roof
|Underlayment shall be applied shingle fashion, parallel to and starting from the |
eave and lapped 4 inches; end laps shall be 6 inches and shall be offset by 6 feet.The underlayment shall be attached to a nailable deck with two staggered rows in
the field of the sheet with a maximum fastener spacing of 12 inches o.c., and onerow at the end and side laps fastened 6 inches o.c. Underlayment shall be attached
using annular ring or deformed shank nails with metal or plastic caps with a nominalcap diameter of not less than 1 inch. Metal caps are required where the ultimate
design wind speed, Vult, equals or exceeds 170 mph. Metal caps shall have a thicknessof not less than 32-gage sheet metal. Power-driven metal caps shall have a
minimum thickness of 0.010 inch. The minimum thickness of the outside edge ofplastic caps shall be 0.035 inch. The cap nail shank shall be not less than 0.083
inch for ring shank cap nails and 0.091 inch for smooth shank cap nails. The capnail shank shall have a length sufficient to penetrate through the roof sheathing or
not less than 3/4 inch into the roof sheathing.
|Metal Roof |
Surface RollRoofing, Slate
|ASTM D226 |
Type IIASTM D4869 Type III
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s.
Asphalt shingles shall be classified in accordance with ASTM D3161, ASTM D7158 or TAS 107. Shingles classified as ASTM D3161 Class D or ASTM D7158 Class G are acceptable for use where Vasd is equal to or less than 100 mph. Shingles classified as ASTM D3161 Class F, ASTM D7158 Class H or TAS 107 are acceptable for use for all wind speeds. Asphalt shingle wrappers shall be labeled to indicate compliance with one of the required classifications, as shown in Table 1507.2.7.1.
CLASSIFICATION OF ASPHALT SHINGLES
|MAXIMUM BASIC WIND
SPEED FROM FIGURE1609.3(1), 1609.3.(2), 1609.3(3), 1609.3(4) or ASCE 7
|Vasd||ASTM D7158||ASTM D3161|
|110||85||D, G or H||D or F|
|116||90||D, G or H||D or F|
|129||100||G or H||D or F|
|142||110||G or H||F|
|155||120||G or H||F|
Base and counter flashing shall be installed as follows:
Base flashing shall be of either corrosion-resistant metal with a minimum thickness provided in Table 1503.2 or mineral surface roll roofing weighing a minimum of 77 pounds per 100 square feet (3.76 kg/m2). Counter flashing shall be corrosion-resistant metal with a minimum thickness provided in Table 1503.2.
Valley linings shall be installed in accordance with the manufacturer's instructions before applying shingles. Valley linings of the following types shall be permitted:
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).
METAL ROOF COVERINGS
|ROOF COVERING |
|STANDARD APPLICATION |
|Aluminum||ASTM B209, 0.024 inch minimum thickness |
for roll-formed panels and 0.019 inch minimumthickness for press-formed shingles.
alloy coated steel
|ASTM A792 AZ 50|
|Cold-rolled copper||ASTM B370 minimum 16 oz/sq. ft and 12 |
oz/sq. ft high yield copper for metal-sheetroof covering systems: 12 oz/sq. ft for preformed
metal shingle systems.
|Copper||16 oz/sq. ft for metal-sheet roof-covering |
systems; 12 oz/sq. ft for preformed metalshingle systems.
|Galvanized steel||ASTM A653 G-90 zinc-coated.a|
|Hard lead||2 lb/sq. ft|
|Lead-coated copper||ASTM B101|
|Prepainted steel||ASTM A755|
|Soft lead||3 lb/sq. ft|
|Stainless steel||ASTM A240/A204M, 300 Series Alloys|
|Terne and terne- |
|Terne coating of 40 lb per double base box, |
field painted where applicable in accordancewith manufacturer's installation instructions.
|Zinc||0.027 inch minimum thickness; 99.995% |
electrolytic high grade zinc with alloy additivesof copper (0.08% — 0.20%), titanium
(0.07% — 0.12%) and aluminum (0.015%).
For SI: 1 ounce per square foot = 0.305 kg/m2, 1 pound per square foot = 4.882 kg/m2, 1 inch = 25.4 mm, 1 pound = 0.454 kg.
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.
SLATE SHINGLE HEADLAP
|4:12 < slope < 8:12||4|
|8:12 < slope < 20:12||3|
|slope = 20:12||2|
For SI: 1 inch = 25.4 mm.
All wood shingles shall be installed in accordance with this chapter and the manufacturer's installation instructions, the Cedar Shake and Shingle Bureau New Roof Construction Manual or RAS 130. The product approval shall state the allowable uplift resistance for the attachment system. The installation of wood shingles shall be limited to roofs where the allowable uplift resistance is equal to or greater than the design uplift pressure for the roof in compliance with Section 1504.1.
Wood shakes shall comply with the requirements of Table 1507.9.6.
WOOD SHAKE MATERIAL REQUIREMENTS
|Wood shakes of naturally durable wood||1||CSSB|
|Taper sawn shakes of naturally durable |
|1 or 2||CSSB|
|Preservative-treated shakes and shingles of||1||CSSB|
|Fire-retardant-treated shakes and shingles||1||CSSB|
|Preservative-treated taper sawn shakes of |
Southern pine treated in accordance withAWPA U1 (Commodity Specification A,
Special Requirement 4.6)
|1 or 2||TFS|
CSSB = Cedar Shake and Shingle Bureau
TFS = Forest Products Laboratory of the Texas Forest Services
Built-up roof covering materials shall comply with the standards in Table 1507.10.2 or UL 55A.
BUILT-UP ROOFING MATERIAL STANDARDS
|Acrylic coatings used in roofing||ASTM D6083|
|Aggregate surfacing||ASTM D1863|
|Asphalt adhesive used in roofing||ASTM D3747|
|Asphalt cements used in roofing||ASTM D3019; D2822; |
|Asphalt-coated glass fiber base sheet||ASTM D4601|
|Asphalt coatings used in roofing||ASTM D1227; D2823; |
|Asphalt glass felt||ASTM D2178|
|Asphalt primer used in roofing||ASTM D41|
|Asphalt-saturated and asphalt-coated |
organic felt base sheet
|Asphalt-saturated organic felt (perforated)||ASTM D226|
|Asphalt used in roofing||ASTM D312|
|Coal-tar cements used in roofing||ASTM D4022; D5643|
|Coal-tar saturated organic felt||ASTM D227|
|Coal-tar pitch used in roofing||ASTM D450; Type I or II|
|Coal-tar primer used in roofing, |
dampproofing and waterproofing
|Glass mat, coal tar||ASTM D4990|
|Glass mat, venting type||ASTM D4897|
|Mineral-surfaced inorganic cap sheet||ASTM D3909|
|Thermoplastic fabrics used in roofing||ASTM D5665, D5726|
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.
Above-deck thermal insulation board shall comply with the standards in Table 1508.2.
[BF] TABLE 1508.2
MATERIAL STANDARDS FOR ROOF INSULATION
|Cellular glass board||ASTM C552|
|Composite boards||ASTM C1289, Type III, IV, V or VI|
|Expanded polystyrene||ASTM C578|
|Extruded polystyrene||ASTM C578|
|Fiber-reinforced gypsum board||ASTM C1278|
|Glass-faced gypsum board||ASTM C1177|
|Lightweight insulating concrete||ASTM C495, ASTM C513, ASTM C796, ASTM C869|
|Mineral fiber insulation board||ASTM C726|
|Perlite board||ASTM C728|
|Polyisocyanurate board||ASTM C1289, Type I or II|
|Wood fiberboard||ASTM C208|
Cooling towers located on the roof deck of a building and greater than 250 square feet (23.2 m2) in base area or greater than 15 feet (4572 mm) in height above the roof deck, as measured to the highest point on the cooling tower, where the roof is greater than 50 feet (15 240 mm) in height above grade plane shall be constructed of noncombustible materials. The base area of cooling towers shall not exceed one-third the area of the supporting roof deck.
Exception: Drip boards and the enclosing construction shall be permitted to be of wood not less than 1 inch (25 mm) nominal thickness, provided the wood is covered on the exterior of the tower with noncombustible material.
The height of mechanical equipment screens located on the roof decks of buildings of Type V construction, as measured from grade plane to the highest point on the mechanical equipment screen, shall be permitted to exceed the maximum building height allowed for the building by other provisions of this code where complying with any one of the following limitations, provided the fire separation distance is greater than 5 feet (1524 mm):
Aerial supports shall be constructed of noncombustible materials.
Exception: Aerial supports not greater than 12 feet (3658 mm) in height as measured from the roof deck to the highest point on the aerial supports shall be permitted to be constructed of combustible materials.
Roof mounted mechanical units shall be mounted on curbs raised a minimum of 8 inches (203 mm) above the roof surface, or where roofing materials extend beneath the unit, on raised equipment supports providing a minimum clearance height in accordance with Table 1510.10.
Exception: In buildings where the existing rooftop equipment, in the opinion of the building official, provides sufficient clearance to repair, recover, replace and/or maintain the roofing system or any of its components, such existing equipment need not comply with Table 1510.10.
CLEARANCE BELOW RAISED ROOF MOUNTED MECHANICAL UNITS
|WIDTH OF MECHANICAL UNIT |
|MINIMUM CLEARANCE ABOVE |
|24 < 36||18|
|36 < 48||24|
|48 < 60||30|
For SI: 1 inch = 25.4 mm.
For definitions outside Sections 1512 through 1525 and accompanied RAS and TAS, see Chapter 2. For the purposes of Sections 1512 through 1525, accompanying RAS, TAS and roofing products approval, roofing terms shall be defined in compliance with ASTM D1079, unless otherwise defined below. The definitions listed below shall take preference. Other terms used herein shall be defined as set forth in Chapter 2 of this code.
AIR PERMEABLE ROOFING SYSTEM. A roofing system consisting of a prepared roof covering over an approved underlayment on a sloped roof. The components within the prepared roof covering are discontinuously laid and small, with unsealed side and head laps. Air permeable roofing systems shall be applied over sheathed decks with either mechanical attachment or a mortar/adhesive bond. Any roofing system with sealed side or head laps shall not be defined as an air permeable roofing system. The authority having jurisdiction may require testing in compliance with TAS 116, to determine whether a roofing system is air permeable.
ANCHOR SHEET. A roofing felt mechanically attached to a nailable deck with approved fasteners to which insulation is then installed in a solid mopping of asphalt. The roofing membrane is then installed to the insulation in the usual manner.
ASTM (ASTM International). A scientific and technical organization that is responsible for the development of standards on characteristics and performance of materials, products, systems, as adopted for the high-velocity hurricane zone.
BASE SHEET. The bottom or first ply of a roofing assembly over which subsequent roofing plies are applied. A base sheet may be designed for mechanical attachment, full or partial adhesion to the substrate.
"CLASS A" ROOFING ASSEMBLY. A roofing assembly that, in combination with the roof slope, has been classified by an approved testing agency, with a listing and follow-up service, as "Class A" in compliance with ASTM E108 or UL 790.
"CLASS B" ROOFING ASSEMBLY. A roofing assembly that, in combination with the roof slope, has been classified by an approved testing agency, with a listing and follow-up service, as "Class B" in compliance with ASTM E108 or UL 790.
"CLASS C" ROOFING ASSEMBLY. A roofing assembly that, in combination with the roof slope, has been classified by an approved testing agency, with a listing and follow-up service, as "Class C" in compliance with ASTM E108 or UL 790.
COUNTERFLASHING. Formed metal or elastomeric sheeting secured on or into a wall, curb, pipe, roof-top unit or other surface to cover and protect the upper edge of a base flashing and its associated fasteners.
DISCONTINUOUS ROOFING SYSTEM. A roofing system with unsealed overlapping components, where the combined roofing system has openings at the point of overlap, applied to a sloped surface with a pitch of 2:12, or greater. Discontinuous roofing systems include asphalt shingles; concrete, clay or metal tile; wood shingles or shakes; and cement fiber roofing systems.
FASTENER WITHDRAWAL RESISTANCE TEST. A static pullout test of mechanical fasteners, which are used to anchor any roofing component, to determine the force required to withdraw a fastener from the substrate. Testing shall be in compliance with the test procedure detailed in TAS 105.
FLAT ROOF TILE PROFILE. Those tiles with less than 1/2-inch (12.7 mm) rise.
FM APPROVALS. A research and testing organization that is responsible for examination and testing of construction and other products on behalf of member insurance companies.
HIGH ROOF TILE PROFILE. Those tiles having a rise-to-width ratio greater than 0.20.
LAP. See NRCA Manual, 4th edition.
LOW ROOF TILE PROFILE. Those tiles having a rise-towidth ratio less or equal than 0.20; except those tiles meeting the flat profile definition.
METAL ROOF PANEL. An interlocking metal sheet having an installed weather exposure equal or greater than 3 square feet (0.3 m2) per sheet.
METAL ROOF SHINGLE. An interlocking metal sheet having an installed weather exposure less than 3 square feet (0.3 m2) per sheet.
MINIMUM CHARACTERISTIC RESISTANCE FORCE. A force or pressure which is representative of data from withdrawal resistance testing; static uplift testing; and/or wind uplift testing after the data has been statistically analyzed to a 95-percent level of precision.
MOMENT. A quantity that represents the effect of a force applied at a particular point in relation to a specific point or axis.
RAS. Roofing Application Standards.
ROOF COVERING. An assembly of multiple field-applied components or a single component designed to weatherproof a building's top surface. A roof covering may be a roofing assembly or form a portion thereof.
ROOF SECTION. A separation or division of a roof area by existing expansion joints, parapet walls, flashing (excluding valleys), difference of elevation (excluding hips and ridges), roof type or legal description; not including the roof area required for a proper tie-off with an existing system.
ROOFING COATINGS, ADHESIVES AND MASTICS. Any and all liquid materials applied to the roofing membrane layer to enhance ultraviolet light resistance; increase resistance to fire; increase reflectivity of the roofing assembly; or, in some way, enhance the performance of the roofing assembly. Roofing coatings, adhesives or mastics shall not contain asbestos materials.
ROOFING SYSTEM. A system of interacting roofing components, generally consisting of membrane or primary roof covering and insulation (not including the roof deck) designed to weatherproof, and sometimes to improve, the building's thermal resistance.
TAS. Testing Application Standard.
UNDERLAYMENT. One or more water-shedding layers applied to a sloped roof prior to the application of a prepared roof covering. The primary purpose of an underlayment is defined as a water shedding layer to function in combination with a prepared roof covering.
WOOD SHAKES. Tapered or straight pieces of red cedar, or other wood types, of widths ranging from 3 inches to 14 inches (76 mm to 356 mm) ranging in lengths from 18 inches to 32 inches (457 mm to 813 mm) applied to a sloped roof, in conjunction with an approved underlayment, forming a discontinuous prepared roof system.
WOOD SHINGLES. Tapered pieces of red cedar, or other wood types, sawn on both faces, of widths ranging from 3 inches to 14 inches (76 mm to 356 mm) and lengths of 16 inches (406 mm), 18 inches (457 mm), and 24 inches (610 mm) applied to a sloped roof forming a discontinuous prepared roof system.
Zero feet to 20 feet (0 to 6.1 m) distance separation measured horizontally from the closest point of any building edge to the nearest point to an adjoining structure, and all buildings with occupation greater than 300 persons.
The proposed method of attachment for tile systems which are considered to be air permeable, shall provide sufficient attachment resistance (Mf) (listed in tile product approval) to meet or exceed the moment of resistance (Mr) as determined by following the procedures outlined in RAS 127. The aerodynamic multiplier (k) needed in RAS 127 shall be part of the tile product approval and shall be derived from the following formula:s
for direct deck application k = (0.156) × (b) × (l)2
for batten application k = (0.144) × (b) × (l)2
Where b (in feet) = exposed width of the tiles
Where l (in feet) = length of tiles
Asphalt types, as defined by ASTM D312, shall be employed in all roofing assemblies. Application of asphalt shall be in compliance with Table 1519.3A and Table 1519.3B or as detailed in the roofing assembly product approval.
SLOPE AND APPLICATION TEMPERATURE CRITERIA
|ASTM D312 |
|Type I||Dead Level||1/4||350 ± 25||375 ± 25|
|Type II||Flat||1/2||400 ± 25||425 ± 25|
|Type III||Steep||3||425 ± 25||450 ± 25|
|Type IV||Special |
Steep(All roof tile
|N/A||450 ± 25||475 ± 25|
1 inch = 25.4 mm; °C = 5/9 (°F - 32).