Building Design and Construction Handbook - Merritt - Ventech!

10.50 SECTION TEN
TABLE 10.26 Minimum Fastening for APA Panel
Roof Sheathing (increased nail schedules may be
required in high wind areas)
Panel
thickness,†
in
Size
Nailing*
Spacing, in
Panel
edge Intermediate
5
⁄16 to 1 8d 6 12‡
11 ⁄8 8d or 10d 6 12‡
* In general, use common smooth or deformed-shank nails
for panels up to 1 in thick. For 1 1 ⁄8-in-thick panels, use 8d
ring- or screw-shank or 10d common smooth-shank nails.
Other approved fasteners, however, may be used.
† For stapling asphalt shingles to panels 5 ⁄16 in or more
thick, use staples with a 15 ⁄16-in minimum crown width and a
1-in-long leg. Space the staples in accordance with the recommendations
of the shingle manufacturer.
‡ For spans of 48 in or more, space the nails 6 in c to c
at all supports.
Deflection limits are 1/180 of the span for total load; 1/240 for live load only.
Nailing requirements for preframed panels are the same as for roof sheathing. See
‘‘APA Design/Construction Guide—Residential and Commercial,’’ APA—The Engineered
Wood Association, for recommended maximum roof loads.
10.12.13 Panel Diaphragms
With only slight design modifications, any panel roof-deck system described in
Arts. 10.12.11 and 10.12.12 will also function as an engineered roof or floor diaphragm
to resist wind and seismic loading.
The ability of a diaphragm to function effectively as a deep beam, transferring
lateral loads to shear walls, is related to the quality of the connections. Nailing is
critical, since shears are transmitted through these fasteners. Common nails provide
required strength. Other nail types may be used when their lateral bearing values
are considered in the design. Load-carrying capacity is highest when the diaphragm
is blocked.
Where 1 1 ⁄8-in roof panels are desired, such as for heavy timber construction,
shear values for 19 ⁄32-in panels are used. Blocked shear values for 1 1 ⁄8-in panels
may be obtained by specifying stapled tongue-and-groove (T&G) edges. Staples
should be 16 ga, 1 in long, with a 3 ⁄8-in crown. They should be driven through the
T&G edges 3 ⁄8-in from the joint so as to penetrate the tongue. Staples should be
spaced at one-half of the boundary nail spacing for Cases 1 and 2, and at one-third
the boundary nail spacing for Case 3 through 6, as illustrated in Table 10.27, which
gives panel and fastening recommendations for roof diaphragms. Panels and framing
are assumed already designed for perpendicular loads. To design a diaphragm,
follow these steps:
1. Determine lateral loads and resulting shears.
2. Determine the nailing schedule (Table 10.27). Consider the load direction with
respect to joints.