FEMA P55 Coastal Construction Manual, Fourth Edition - Mad Cad

11 Designing the builDing envelope Volume II
Figure 11-34.
A bleeder strip (doublearrow)
that was used at
a rake blow-off; lack of
contact between the tab
of the overlying shingle
and the bleeder’s self-seal
adhesive (upper arrow).
Estimated wind speed: 125
mph. Hurricane Katrina
(Mississippi, 2005)
Figure 11-35.
Inadequate sealing of the
self-sealing adhesive at
a hip as a result of the
typical hip installation
procedure. Estimated
wind speed: 105 mph.
Hurricane Katrina
(Mississippi, 2005)
Four fasteners per shingle are normally used where the basic wind speed is less than 115 mph.16 Where
the basic wind speed is greater than 115 mph, six fasteners per shingle are recommended. Fact Sheet 7.3 in
FEMA P-499 provides additional guidance on shingle fasteners. Storm damage investigations have shown
that signifcant fastener mislocation is common on damaged roofs. When nails are too high above the
nail line, they can miss the underlying shingle headlap or have inadequate edge distance, as illustrated
16 The 115-mph basic wind speed is based on ASCE 7-10, Risk Category II buildings. If ASCE 7-05 or an earlier version is used, the
equivalent wind speed trigger is 90 mph.
11-34 COASTAL CONSTRUCTION MANUAL