1507.4 Metal Roof Panels
Minimum slopes for metal roof panels shall comply with the following:
- The minimum slope for lapped, nonsoldered seam metal roof panels without applied lap sealant shall be three units vertical in 12 units horizontal (25-percent slope).
- The minimum slope for lapped, nonsoldered seam metal roof panels with applied lap sealant shall be one-half unit vertical in 12 units horizontal (4-percent slope). Lap sealants shall be applied in accordance with the approved manufacturer's installation instructions.
- The minimum slope for standing-seam metal roof panel systems shall be one-quarter unit vertical in 12 units horizontal (2-percent slope).
Metal-sheet roof covering systems that incorporate supporting structural members shall be designed in accordance with Chapter 22. Metal-sheet roof coverings installed over structural decking shall comply with Table 1507.4.3(1). The materials used for metal-sheet roof coverings shall be naturally corrosion resistant or provided with corrosion resistance in accordance with the standards and minimum thicknesses shown in Table 1507.4.3(2).
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-coateda.|
|Hard lead||2 lbs./sq. ft.|
|Lead-coated copper||ASTM B101|
|Prepainted steel||ASTM A755|
|Soft lead||3 lbs./sq. ft.|
|Stainless steel||ASTM A240, 300 Series Alloys|
|Terne and terne-|
|Terne coating of 40 lbs. 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.
- For Group U buildings, the minimum coating thickness for ASTM A653 galvanized steel roofing shall be G-60.
MINIMUM CORROSION RESISTANCE
|55% Aluminum-zinc alloy coated steel||ASTM A792 AZ 50|
|5% Aluminum alloy-coated steel||ASTM A875 GF60|
|Aluminum-coated steel||ASTM A463 T2 65|
|Galvanized steel||ASTM A653 G-90|
|Prepainted steel||ASTM A755a|
- Paint systems in accordance with ASTM A755 shall be applied over steel products with corrosion-resistant coatings complying with ASTM A463, ASTM A653, ASTM A792 or ASTM A875.
- Galvanized fasteners shall be used for steel roofs.
- Copper, brass, bronze, copper alloy or 300 series stainless-steel fasteners shall be used for copper roofs.
- Stainless-steel fasteners are acceptable for all types of metal roofs.
- Aluminum fasteners are acceptable for aluminum roofs attached to aluminum supports.