Spacing of Screws Gypsum Board

(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,

    (b)   not more than 400 mm o.c. on vertical wall supports where the supports are not more than 406 mm o.c.

    (4)  Except as permitted by Sentence (5), for single-layer application on walls, where gypsum board is required to provide bracing, lateral support 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.

    (5)  Where a fire-resistance rating is determined based on Table 1 of MMAH Supplementary Standard SB-3, “Fire and Sound Resistance of Building Assemblies”, Sentence (4) need not apply for the purpose of fire protection.

    (6)  Screws shall be located not less than 10 mm from the side or edge of the board.

    (7)  Screws shall be driven so that the heads do not puncture the paper.

Article 9.29.5.9. Ontario Regulation 332/12 Building Code,   Information published by oncodes.ca for educational purposes only.

Nail and Screw Popping

Popping can occur with both drywall nails and screws. It results from wood shrinkage and will likely occur, if at all, during the first heating season as the moisture content in the wood acclimatizes to the average humidity level in the house. Popping can be minimized by using framing lumber with a moisture content of not more than 19 per cent as stipulated in the NBC and nails or screws that are just long enough
to meet code requirements so that a minimum length of fastener is embedded in the area where shrinkage takes place.

Source : Canada Mortgage and Housing Corporation (CMHC)