Basement windows 101: what you need to know

​In Ontario, a basement bedroom requires an egress window regardless of how often it is used. Under the Ontario Building Code (OBC), the requirement is based on whether the room is designed or used for sleeping, not the frequency of use. 

If the room is enclosed and intended for sleeping (even if only for occasional guests), it must comply with egress safety regulations. 

Why "Occasional" Use Doesn't Matter

• Safety Risk: The code is designed to protect occupants who are sleeping, regardless of whether they are there once a year or every night. A fire in a basement can quickly cut off the main exit stairs.
• Legal & Insurance Issues: A basement bedroom without a compliant egress window is considered illegal in Ontario. It can cause issues with home insurance claims in the event of a fire and create difficulties when selling the home. 
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Ontario Egress Window Requirements

​To be compliant, the window must meet specific standards: 

• Unobstructed Opening: The clear open space must be at least 0.35 square metres (3.77 sq. ft.).
• Minimum Dimension: No dimension (height or width) of the openable part can be less than 380 mm (15 inches).
• Operation: The window must open easily from the inside without keys, tools, or special knowledge.
• Window Well: If below ground, the well must provide at least 550 mm (22 inches) of clear space in front of the window for escape.
• Sill Height: The bottom of the opening should not be more than 1.5 metres (59 inches) above the floor, although some variations exist, and a permanent step can be added. 
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Alternatives

• Direct Exit: If the bedroom has a door that leads directly outside (like a walk-out basement) without needing to go through the rest of the house, an egress window is not required.
• Sprinkler System: If the house has a fully installed fire sprinkler system, the window requirement may be waived, though this is rarely done in residential retrofits. 
  
  

Disclaimer: Always check with your local municipality (building department) for specific by-laws, as they can be stricter than the provincial code.
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