The Ontario Building Code | Orientation of Studs
220.127.116.11. Orientation of studs
(1) Except as permitted in Sentences (2) and (3), all studs shall be placed at right angles to the wall face.
(2) studs on the flat are permitted to be used in gable ends of roofs that contain only unfinished space or in non-loadbearing interior walls within the limits described in Article 18.104.22.168.
(3) wall studs that support only a load from an attic not accessible by a stairway are permitted to be placed on the flat within the limits permitted in Article 22.214.171.124. provided,
(a) the studs are clad on at least one side with plywood, OSB or waferboard sheathing fastened to the face of the studs with a structural adhesive, and
(b) the portion of the roof supported by the studs does not exceed 2.1 m in width.