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 ROOFING / WATERPROOFING STANDARDS (continued - page 2 of 3)
Professional Guidance (continued)
Asphalt Shingles Roofs
- Specify a 2-ply laminated shingle, conforming to ASTM D3462, with a minimum 50-year material warranty and a minimum 15-year non-prorated labor and material watertightness warranty (i.e. Certainteed-Sure Start Plus 5 Star, GAF-Golden Pledge, Malarkey-steep slope system, etc.)
- In humid and wet climates, specify algae resistant shingles
- In hailstorm areas, specify impact resistance shingles passing an UL 2218 test for Class 3 or 4.
- In high wind areas, (greater than 90 mph) specify wind resistant shingles rating to wind speed determined by ASCE 7, and require a 10-year wind warranty
- In snow/ice climates, specify fully adhered moisture protection underlayment extending from the eave to 3 feet from the inside face of the exterior wall, at valleys, ridges and along dormer or other walls. Use cold roof design technology if possible.
- Fasten shingles with minimum12 gauge corrosion resistant nails only. Minimum nail head diameter shall be 3/8”. Shank shall penetrate minimum of ¾” in wood decking or completely through plywood decking.
- Asphalt-saturated felt underlayment shall meet ASTM D 226 and/or D 4869. Use double layers on roof slopes less than 4:12.
- Specify roof perimeter edge metal and step flashing at walls
and chimneys.
- Minimum slope 3:12.
- Specify open, closed, or woven valleys
Metal Roofs
- Specify metal roof manufacturers who offer Full System Manufacturer’s Roofing Warranty for 20-year labor and material warranty, for the installed cost of roof, to repair leaks in the roof panels, flashing and trim resulting from defects in materials or workmanship. Roof manufacturers shall be required to inspect the work during construction (i.e. AEPS span-weather tightness, Berridge-Total Single Source, MBCJ-single source III, etc.).
- Verify with manufacturer their underlayment requirement for the 20-year warranty
- Steep roof (hydrokinetic) roofs shall pass air and water infiltration tests per ASTM E1646 and E1680. Low slope (hydrostatic) roofs shall pass water infiltration tests per ASTM E2140. Submit test report.
- Specify Kynar 500 or Hylar 5000 paint finish on metal panels which require paint.
- Specify 22 gage galvalume/zincalume and/or galvanized metal roofs. For structures located in coast regions use 0.040” aluminum or 20 oz copper. For high profile structures, use any of the above 3 materials.
- For architectural panel roofs, specify snap type standing or batten seam with continuous length panels. Panel should be kept off substrate by manufacturer’s clips. Double lock standing seams should only be used in high snow areas where snow will accumulate on the roof over the winter
- For structural or structural/architectural panel roofs, specify concealed fasteners and clips for panel attachment. No fasteners shall be located in the pan of the panel except at
the ridge.
- Panels and trim shall be rolled formed at the manufacturer’s prime manufacturing plant
- Specify manufactured prepared shop drawing on a minimum 24” by 36” sheet.
- Metal shingles and shingle panels to be used on steep slope (3:12 or greater). Investigate the bottom, top and side of each shingle to determine the interlocking mechanism and watertightness of the lap, joint and seam. Examine ridge, valley, hip and perimeter flashings profiles for watertightness. These products maybe problematic on roofs that retain snow for long periods of time.
- Specify rosin paper slip sheet under all architectural metal roofs
- In snow/ice climates or as required for warranty, specify fully adhered moisture protection underlayment extending from the eave to 3 feet from the inside face of the exterior wall, at valleys, ridges and along dormer or other walls. Use cold roof design technology when possible.
- Specify self-adhered high temperature underlayment.
Clay and Concrete Tile Roofs
- Specify clay tile manufacturers who offer a 20-year labor and material warranty, for the installed cost of roof, to replace defective tiles resulting from defects in materials or workmanship
- Clay Tile shall meet or exceed ASTM C1167 Grade 1 requirements for durability and ASTM C1167 Type I ,
for appearance
- Concrete tile shall meet or exceed ASTM C1492 requirements.
- In freeze/thaw climates specify clay tile manufacturers who have tiles with a moisture absorption rate of less than 1% per ASTM C67. Concrete tile shall have a minimum compressive strength of 7500 psi, shall not have more than 1% loss in dry weight per ASTM C67 and not absorb more than 8% of the dry weight in ASTM C140 immersion test.
- Specify 2 layers of 30# asphalt-saturated felt underlayment meeting ASTM D 226 and/or D 4869.
- In snow/ice climates or as required for warranty, specify fully adhered moisture protection underlayment extending from the eave to 3 feet from the inside face of the exterior wall, at valleys, ridges and along dormer or other walls. Use cold roof design technology if possible.
- In hailstorm areas, specify manufacturers who provide a minimum 10-year hail warranty covering material replacement of damaged tiles
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