Ontario Egress Window Requirements

An egress window (or door) is an emergency escape and rescue opening that lets occupants exit a room to the exterior and allows firefighters to enter. It is not the same as a standard operable window used only for ventilation.

Egress openings are required for bedrooms and certain other rooms unless another compliant exit path is available. In practice, every basement bedroom and most secondary-suite sleeping rooms need a compliant egress window or exterior door.

The Ontario Building Code Part 9 sets minimum openable area and minimum clear dimensions for the openable portion — commonly at least 0.35 m² with no dimension less than 380 mm. The window must open without keys, tools, or special knowledge, and stay open without continuous force in many configurations.

Sill height above the finished floor is limited so the opening is usable in an emergency. Windows placed too high fail inspection even when the glass area looks large enough. Casement and awning styles often meet dimension rules more easily than small sliders.

When the bottom of the opening is below grade, a window well is required with minimum horizontal projection and clear area. Deeper wells typically need a permanent ladder or steps. Wells must drain and remain clear of debris and covers that block escape.

Basement renovations that add bedrooms are the most common trigger for egress upgrades. Existing hopper or slider windows are often too small. Enlarging the opening may require cutting foundation concrete, installing a new well, and addressing waterproofing and structural lintels.

Secondary suites and basement apartments combine egress with fire separation, ceiling height, and smoke-alarm requirements. A legal suite bedroom needs compliant egress even if the suite also has an exterior door — confirm travel paths and bedroom rules with your AHJ.

Always verify the current OBC edition and local amendments. This article is general guidance — measure your finished floor, sill, and well against the code and confirm with your building department before ordering windows.