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2508.1 General.
Gypsum board, gypsum panel products and gypsum plaster construction shall be of the materials listed in Tables 2506.2 and 2507.2. These materials shall be assembled and installed in compliance with the appropriate standards listed in Tables 2508.1 and 2511.1.1, and Chapter 35.
Material | Standard |
Material | Standard |
Gypsum board and gypsum panel products | GA-216; ASTM C 840 |
Gypsum sheathing and gypsum panel products | ASTM C 1280 |
Gypsum board (Interior) | ASTM C 1396 |
Gypsum board (Exterior) | ASTM C 1396 |
Gypsum veneer base | ASTM C 844 |
Interior bathing and furring | ASTM C 841 |
Steel framing for gypsum board and gypsum panel products | ASTM C 754; C 1007 |
2508.2 Limitations.
Gypsum wallboard or gypsum plaster shall not be used in any exterior surface where such gypsum construction will be exposed directly to the weather. Gypsum wallboard shall not be used where there will be direct exposure to water or continuous high humidity conditions beyond the published recommendations of the manufacturer. Gypsum sheathing shall be installed on exterior surfaces in accordance with ASTM C 1280.
2508.2.1 Weather protection.
Gypsum wallboard, gypsum lath or gypsum plaster shall not be installed until weather protection for the installation is provided.
2508.3 Single-ply application.
Edges and ends of gypsum board and gypsum panel products shall occur on the framing members, except those edges and ends that are perpendicular to the framing members. Edges and ends of gypsum board and gypsum panel products shall be in moderate contact except in concealed spaces where fire-resistance-rated construction, shear resistance or diaphragm action is not required.
2508.3.1 Floating angles.
Fasteners at the top and bottom plates of vertical assemblies, or the edges and ends of horizontal assemblies perpendicular to supports, and at the wall line are permitted to be omitted except on shear resisting elements or fire-resistance-rated assemblies. Fasteners shall be applied in such a manner as not to fracture the face paper with the fastener head.
2508.4 Joint treatment.
Gypsum board and gypsum panel product fire-resistance-rated assemblies shall have joints and fasteners treated.
Exception: Joint and fastener treatment need not be provided where any of the following conditions occur:
1. Where the gypsum board or the gypsum panel product is to receive a decorative finish such as wood paneling, battens, acoustical finishes or any similar application that would be equivalent to joint treatment.
2. On single-layer systems where joints occur over wood framing members.
3. Square edge or tongue-and-groove edge gypsum board (V-edge), gypsum panel products, gypsum backing board or gypsum sheathing.
4. On multilayer systems where the joints of adjacent layers are offset.
5. Assemblies tested without joint treatment.
2508.5 Horizontal gypsum board or gypsum panel product diaphragm ceilings.
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.
Material | Thickness of Material (Minimum) (inches) | Spacing of Framing Members (inches) | Shear Value a, b (PLF of Ceiling) | Minimum Fastener Size |
Gypsum board or gypsum panel product | 1/2 | 16 o.c. | 90 | 5d cooler or wallboard nail; 1 5/8-inch long; 0.086-inch shank; 15/64-inch head
c |
Gypsum board or gypsum panel product | 1/2 | 24 o.c. | 70 | 5d 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.
2508.5.1 Diaphragm proportions.
The maximum allowable diaphragm proportions shall be 1 1/2:1 between shear resisting elements. Rotation or cantilever conditions shall not be permitted.
2508.5.2 Installation.
Gypsum board or gypsum panel products used in a horizontal diaphragm ceiling shall be installed perpendicular to ceiling framing members. End joints of adjacent courses of gypsum board shall not occur on the same joist.
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