Egress window requirements for basement bedrooms in Ontario come down to a simple idea: if there is a fire, a person sleeping in the basement must be able to get out through a window without a key, a tool or a ladder that is out of reach. The numbers are specific. A bedroom egress window needs an unobstructed opening of at least 0.35 square metres, with no dimension under 380 mm (about 15 in). Getting those numbers right, and building the window well around them, is one of the most common challenges in basement renovations.
Why egress is a hard requirement
Basements are the part of a house where fire and smoke can trap people. Stairs may be the only way out, and if the stairwell is blocked by smoke or flame, a window is the only other route. For that reason, rooms used for sleeping need a clear secondary way out, and the Ontario Building Code spells out how that must work. It is also a core item when a basement is converted to a legal second unit, since a tenant must be able to escape as easily as the owners.
Confirm the rules that apply to your house with the municipal building department. We describe general requirements here, and your layout, ceiling height and exit paths may add conditions.
Egress window requirements for basements in Ontario: what the numbers mean
The 0.35 square metre figure is the clear opening you get once the window is open, not the size of the glass or the frame. A big casement window can have a small clear opening if the sash hangs in the way, and a sliding window gives you only half of its width. That is why a window that looks large on a drawing can fail when measured.
- Measure the unobstructed opening with the window fully open, from inside the frame.
- Check that no dimension, height or width, is below 380 mm (about 15 in).
- Make sure it opens from the inside without keys or special tools.
- Confirm the opening is not blocked by bars, screens that cannot be removed, or fixed furniture.
Casement and awning windows often work well for egress because they open fully, and many manufacturers list the clear opening area for each model. Use that data when choosing.
Window wells: where most of the work is
When the window sits below ground level, it needs a window well. The well must be large enough to let a person climb out, and it must be arranged so that a person is not trapped inside it. Deeper wells may need a permanent ladder or steps, as required by the Code, and the well should provide a clear space in front of the window to operate it and climb out.
Drainage is just as important. A well that collects water will leak into your basement and wash out the foundation. Ask your contractor how the well will drain, whether it connects to the weeping tile or a dry well, and how water will be kept out of the opening. A properly designed well also keeps out leaves and snow, so a clear cover that does not block escape is often worth considering. Confirm any cover design with the building department, because it must be easy to open from inside.
Cutting into the foundation
If your basement has only small high windows, you will need to enlarge or add an opening. That means cutting concrete or block, and it is not a casual job. A new opening affects the strength of the wall, so it often needs structural review and an engineered detail for a lintel or support above. In many cases a building permit is needed, so confirm with your city before cutting.
Planning also affects the outside. The soil next to the wall must be excavated to form the well, so check for buried gas, water or electrical lines, as well as for grade, fences, decks and the neighbour’s property line. We prepare permit and engineered drawings in-house, with a licensed P.Eng stamp where required, and you can read more on our design and engineered drawing page.
What drives the cost
We do not quote a price for a single window here because it varies so widely. The factors include:
- Whether you are enlarging an existing opening or cutting a new one.
- Foundation type, such as poured concrete or block.
- Depth of the window well and the drainage needed.
- Window type and quality.
- Access for excavation, including landscaping, decks and walkways.
- Engineering, permits and restoration of the outside.
If egress is part of a bigger project, the totals matter more. As typical ranges only, a recreational basement finish runs about $35,000-$65,000, and a legal suite without underpinning about $65,000-$100,000. Every home differs, and a site visit gives you the real number. Our basement renovation page and the guide to legal basement suites in Toronto show how egress fits into the larger scope.
Common mistakes
- Buying a window by glass size rather than clear opening area.
- Forgetting that a deep well needs to be climbable.
- Ignoring drainage and then dealing with a wet room.
- Finishing the room before the opening is approved or inspected.
- Putting a bed under a window that cannot be reached.
Frequently Asked Questions
Does every basement room need an egress window?
Generally the requirement applies to rooms used for sleeping. Confirm the details for your layout with your building department.
Can a door count as egress?
In some layouts, a door to the outside can serve as an exit, but the rules depend on the plan. Ask the building department.
Can you install an egress window yourself?
Cutting a foundation wall has structural and safety implications and often needs a permit. A qualified contractor with engineering support is the safer route.
Will the window well flood?
Not if it is designed with proper drainage. Ask how water will be handled.
If you are working through egress window requirements for a basement in Ontario, call us at 647-914-2150 or book a free site visit. GoGajic Construction, 131 Minerva Ave, Toronto, will check your walls, measure the openings and explain your options.
