FEMA P55 Coastal Construction Manual, Fourth Edition - Mad Cad

11 Designing the builDing envelope Volume II
Figure 11-42.
Extensive blow-off
of mortar-set tiles.
Hurricane Charley
(Florida, 2004)
Figure 11-43.
Blown-off adhesive-set tile. Note the very small contact area of the foam at the tile heads (left side of the tiles)
and very small contact at the nose (circles). Estimated wind speed: 140 to 160 mph. Hurricane Charley
(Florida, 2004)
Damage investigations have revealed that blow of of hip and ridge failures are common (see Figures 11-39,
11-45, and 11-46). Some of the failed hip/ridge tiles were attached with mortar (see Figure 11-45), while
others were mortared and mechanically attached to a ridge board. At the roof shown in Figure 11-46, the hip
tiles were set in mortar and attached to a ridge board with a single nail near the head of the hip tile.
Because of the brittle nature of tile, tile is often damaged by wind-borne debris, including tile from nearby
buildings or tile from the same building (see Figure 11-47).
At houses on the coast, fasteners and clips that are used to attach tiles are susceptible to corrosion unless they
are stainless steel. Figure 11-48 shows a 6-year-old tile roof on a house very close to the ocean that failed
because the heads of the screws attaching the tile had corroded of. Stainless steel straps, fasteners, and clips
are recommended for roofs within 3,000 feet of an ocean shoreline (including sounds and back bays).
11-40 COASTAL CONSTRUCTION MANUAL