FEMA P55 Coastal Construction Manual, Fourth Edition - Mad Cad

11 Designing the builDing envelope Volume II
Figure 11-49.
Area of the roof where
tiles were not nailed to
batten strips. Northridge
Earthquake (California,
1994)
Figure 11-50.
Tiles that were nailed
to thin wood sheathing.
Northridge Earthquake
(California, 1994)
Tiles that are attached by only one fastener experience eccentric loading. Tis problem can be overcome
by specifying wind clips near the nose of the tile or a bead of adhesive between the tiles at the headlap.
Two-piece barrel (i.e., mission) tiles attached with straw nails can slide downslope a few inches because
of deformation of the long straw nail. Tis problem can be overcome by specifying a wire-tied system or
proprietary fasteners that are not susceptible to downslope deformation.
When tiles are cut to ft near hips and valleys, the portion of the tile with the nail hole(s) is often
cut away. Figure 11-51 shows a tile that slipped out from under the hip tiles. Te tile that slipped
was trimmed to ft at the hip. Te trimming eliminated the nail holes, and no other attachment was
provided. Te friction ft was inadequate to resist the seismic forces. Tiles must have supplemental
securing to avoid displacement of these loose tiles.
11-44 COASTAL CONSTRUCTION MANUAL