This post is intended to educate homeowners regarding basement egress window requirements as per the Ontario Building Code (OBC). The primary safety reason behind these requirements is about occupants being able to exit the basement in the case of an emergency.

The OBC requires homeowners to have an egress window on each floor that contains a bedroom but does not have an exit door on the same level as the bedroom. The OBC regulated minimum dimensions for the openable part of the window must be at least 0.35 sm (just under 4sq. ft.) in area with the minimum length requirement of 380 mm (15″) for both the height and the width. The code also mentions that in the case where the basement window is below grade and is protected by a window well on the exterior of the house, the required clearance provided in front of the window is not less than 550 mm (21.5″).

Where window opens into a window well, a clearance of not less than 550 mm (21.5″) shall be provided in front of the window.
Where the sash of a window referred to in a Sentence (5) swings towards the window well, the operation of the sash shall not reduce the clearance in a manner that would restrict escape in an emergency.

A basement bedroom in Ontario does not require an egress window in the actual bedroom; the egress window just needs to be on the same floor as the bedroom.
This post is only a summary of the main issues in the Ontario Building Code that affect basement egress window requirements. For the full document see OBC 9.9.10.1