9.29.5.9.Spacing of Screws

(1) For single-layer application on a ceiling, screws shall be spaced not more than 300 mm o.c. on ceiling supports. (2) Where the ceiling sheets are supported by the wall sheets around the perimeter of the ceiling, this support may be considered as equivalent to screwing at this location. (3) Except as required by Sentence (4), for single-layer application on walls, screws shall be spaced (a) not more than 300 mm o.c. on vertical wall supports where the supports are more than 400 mm o.c., or (b) not more than 400 mm o.c. on vertical wall supports where the supports are not more than 400 mm o.c. (4) Except as provided in Sentence (5), for single-layer application on walls, where gypsum board provides required bracing in braced wall panels, lateral support for studs, or fire protection, screws shall be spaced not more than 300 mm o.c. on (a) vertical wall supports, and (b) top and bottom plates. (See Article 9.23.10.2. and Section 9.10.) (5) Where a fire-resistance rating is determined based on Table 1 of MMAH Supplementary Standard SB-3, “Fire and Sound Resistance Tables,” Sentence (4) need not apply for the purpose of fire protection. (6) Screws shall be located not less than 10 mm from the edge of the board. (7) Screws shall be driven so that the heads do not puncture the paper.