2508.5 Horizontal gypsum board or gypsum panel product diaphragm ceilings.
BC § 2508.5
Gypsum board or gypsum panel products shall be permitted to be used on wood joists to create a horizontal diaphragm ceiling in accordance with Table 2508.5. Table 2508.5Shear Capacity for Horizontal Wood-Frame Gypsum Board Diaphragm Ceiling Assemblies MaterialThickness of Material (Minimum) (inches)Spacing of Framing Members (inches)Shear Value a, b(PLF of Ceiling)Minimum Fastener SizeGypsum board or gypsum panel product1/216 o.c.905d cooler or wallboard nail; 1 5/8-inch long; 0.086-inch shank; 15/64-inch head cGypsum board or gypsum panel product1/224 o.c.705d cooler or wallboard nail; 1 5/8-inch long; 0.086-inch shank; 15/64-inch head c For SI: 1 inch = 25.4 mm, 1 pound per foot = 14.59 N/m. a. Values are not cumulative with other horizontal diaphragm values and are for short-term wind or seismic loading. Values shall be reduced 25 percent for normal loading. b. Values shall be reduced 50 percent in Seismic Design Categories D, E and F. c. 1 1/4-inch, No. 6 Type S or W screws are permitted to be substituted for the listed nails.
