FEMA P55 Coastal Construction Manual, Fourth Edition - Mad Cad

11 Designing the builDing envelope Volume II
Shingles manufactured with a wide nailing zone provide roofng mechanics with much greater opportunity
to apply fasteners in the appropriate locations.
Shingle damage is also sometimes caused by installing shingles via the raking method. With this method,
shingles are installed from eave to ridge in bands about 6 feet wide. Where the bands join one another, at
every other course, a shingle from the previous row needs to be lifted up to install the end nail of the new
band shingle. Sometimes installers do not install the end nail, and when that happens, the shingles are
vulnerable to unzipping at the band lines, as shown in Figure 11-38. Raking is not recommended by the
National Roofng Contractors Association or the Asphalt Roofng Manufacturers Association.
Figure 11-38.
Shingles that unzipped at
the band lines because
the raking method was
used to install them.
Estimated wind speed:
135 mph. Hurricane
Katrina (Mississippi,
2005)
11.5.1.2 Hail
Underwriters Laboratories (UL) 2218 is a method of assessing simulated hail resistance of roofng systems.
Te test yields four ratings (Classes 1 to 4). Systems rated Class 4 have the greatest impact resistance. Asphalt
shingles are available in all four classes. It is recommended that asphalt shingle systems on buildings in areas
vulnerable to hail be specifed to pass UL 2218 with a class rating that is commensurate with the hail load.
Hail resistance of asphalt shingles depends partly on the condition of the shingles when they are exposed to
hail. Shingle condition is likely to decline with roof age.
11.5.2 Fiber-Cement Shingles
Fiber-cement roofng products are manufactured to simulate the appearance of slate, tile, wood shingles,
or wood shakes. Te properties of various fber-cement products vary because of diferences in material
composition and manufacturing processes.
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