The Ontario Building Code | Combination Rooms
9.5.1.4. Combination Rooms
(1) Two or more areas may be considered as a combination room if the opening between the areas occupies the larger of 3 m2 or 40% or more of the wall measured on the side of the dependent area.
(2) Where the dependent area is a bedroom, direct passage shall be provided between the two areas.
(3) The opening required in Sentence (1) shall not contain doors or windows.