Screws for Fastening Gypsum Board

(1)  Screws for fastening gypsum board to wood supports shall conform to ASTM C1002, “Steel Self-Piercing Tapping Screws for the Application of Gypsum Panel Products or Metal Plaster Bases to Wood Studs or Steel Studs”.

Article 9.29.5.7. Ontario Regulation 332/12 Building Code,   Information published by oncodes.ca for educational purposes only.

Screw Attachment

Special drywall screws are often used to fasten gypsum board using screw guns. Screws are usually spaced 300 mm (12 in.) on centre at both the edge and intermediate supports. The distance can be increased to 400 mm (16 in.) on walls when the supports are not more than 400 mm (16 in.) on centre. Where gypsum board provides required bracing in braced wall panels in areas exposed to high wind or earthquake forces, the screw spacing must not be more than 300 mm (12 in.).

If two layers of gypsum board are needed, such as for sound control or additional fire rating, fasten the boards in the usual manner with nails or screws. The fasteners for the second layer must penetrate as much as for the first layer.

If gypsum board is not to be directly attached to the structural members but instead to channels (for example, resilient metal channels) for sound control and/or fire resistance, the channel must be secured to the structure and the gypsum board affixed to the channel.

Source : Canada Mortgage and Housing Corporation (CMHC)