Page 468 - 2018_IRC

ROOF ASSEMBLIES

TABLE R905.10.3(2) R905.12.1 Slope. Thermoset single-ply membrane roofs
MINIMUM CORROSION RESISTANCE
shall have a design slope of not less than one-fourth unit
55% aluminum-zinc-alloy-coated steel ASTM A792 AZ 50 vertical in 12 units horizontal (2-percent slope) for drain-
5% aluminum alloy-coated steel ASTM A875 GF60 age.
Aluminum-coated steel ASTM A463 T2 65 R905.12.2 Material standards. Thermoset single-ply
Galvanized steel ASTM A653 G-90 roof coverings shall comply with ASTM D4637 or ASTM
D5019.
a
Prepainted steel ASTM A755
R905.12.3 Application. Thermoset single-ply roofs shall
a. Paint systems in accordance with ASTM A755 shall be applied over steel be installed in accordance with this chapter and the manu-
products with corrosion-resistant coatings complying with ASTM A792,
ASTM A875, ASTM A463, or ASTM A653. facturer’s instructions.
R905.10.4 Attachment. Metal roof panels shall be R905.13 Thermoplastic single-ply roofing. The installation
secured to the supports in accordance with this chapter and of thermoplastic single-ply roofing shall comply with the pro-
the manufacturer’s installation instructions. In the absence visions of this section.
of manufacturer’s installation instructions, the following
fasteners shall be used: R905.13.1 Slope. Thermoplastic single-ply membrane
roofs shall have a design slope of not less than one-fourth
1. Galvanized fasteners shall be used for steel roofs.
unit vertical in 12 units horizontal (2-percent slope).
2. Copper, brass, bronze, copper alloy and 300-series
stainless steel fasteners shall be used for copper roofs. R905.13.2 Material standards. Thermoplastic single-ply
roof coverings shall comply with ASTM D4434, ASTM
3. Stainless steel fasteners are acceptable for metal D6754 or ASTM D6878.
roofs.
R905.13.3 Application. Thermoplastic single-ply roofs
R905.10.5 Underlayment. Underlayment shall comply shall be installed in accordance with this chapter and the
with Section R905.1.1. manufacturer’s instructions.
R905.11 Modified bitumen roofing. The installation of R905.14 Sprayed polyurethane foam roofing. The installa-
modified bitumen roofing shall comply with the provisions of tion of sprayed polyurethane foam roofing shall comply with
this section and the manufacturer’s approved installation the provisions of this section.
instructions.
R905.14.1 Slope. Sprayed polyurethane foam roofs shall
R905.11.1 Slope. Modified bitumen roofing shall have a have a design slope of not less than one-fourth unit verti-
design slope of not less than one-fourth unit vertical in 12 cal in 12 units horizontal (2-percent slope) for drainage.
units horizontal (2-percent slope) for drainage.
R905.14.2 Material standards. Spray-applied polyure-
R905.11.2 Material standards. Modified bitumen roof- thane foam insulation shall comply with ASTM C1029,
ing shall comply with the standards in Table R905.11.2. Type III or IV or ASTM D7425.
TABLE R905.11.2 R905.14.3 Application. Foamed-in-place roof insulation
MODIFIED BITUMEN ROOFING MATERIAL STANDARDS shall be installed in accordance with this chapter and the
MATERIAL STANDARD manufacturer’s instructions. A liquid-applied protective
Acrylic coating ASTM D6083 coating that complies with Table R905.14.3 shall be
Asphalt adhesive ASTM D3747 applied not less than 2 hours nor more than 72 hours fol-
Asphalt cement ASTM D3019 lowing the application of the foam.
Asphalt coating ASTM D1227; D2824
TABLE R905.14.3
Asphalt primer ASTM D41 PROTECTIVE COATING MATERIAL STANDARDS
Modified bitumen roof ASTM D6162; D6163; D6164; MATERIAL STANDARD
membrane D6222; D6223; D6298
Acrylic coating ASTM D6083
R905.11.2.1 Base sheet. A base sheet that complies Silicone coating ASTM D6694
with the requirements of Section 1507.11.2 of the Inter- Moisture-cured polyurethane coating ASTM D6947
national Building Code, ASTM D1970, or ASTM
D4601 shall be permitted to be used with a modified R905.14.4 Foam plastics. Foam plastic materials and
bitumen cap sheet. installation shall comply with Section R316.

R905.11.3 Application. Modified bitumen roofs shall be R905.15 Liquid-applied roofing. The installation of liquid-
installed in accordance with this chapter and the manufac- applied roofing shall comply with the provisions of this sec-
turer’s instructions. tion.
R905.12 Thermoset single-ply roofing. The installation of R905.15.1 Slope. Liquid-applied roofing shall have a
thermoset single-ply roofing shall comply with the provisions design slope of not less than one-fourth unit vertical in 12
of this section. units horizontal (2-percent slope).

2018 INTERNATIONAL RESIDENTIAL CODE ® 443
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