The Ontario Building Code | Materials and Thickness

9.30.2.2. Materials and Thickness

(1) panel-type underlay shall be not less than 6 mm thick and shall conform to,

(a) ANSI A208.1, "Particleboard",

(b) CAN/cgsb-11.3-M, "Hardboard",

(c) CSA O115-M, "Hardwood and Decorative Plywood",

(d) CSA O121, "Douglas Fir Plywood",

(e) CSA O151, "Canadian Softwood Plywood",

(f) CSA O153-M, "Poplar Plywood", or

(g) CSA O437.0, "OSB and Waferboard".