What an egress window is for
An egress window is a second way out of a bedroom when the door is blocked by fire — and a way in for a firefighter. The Ontario Building Code (OBC) treats it as life-safety equipment, which is why it is one of the inspections a basement apartment cannot skip and one of the most common reasons a suite fails its first inspection. Ordinary basement windows almost never qualify: the typical 1970s hopper window gives a clear opening of roughly 0.15 m², less than half the minimum.
The four numbers inspectors check
| Requirement | Ontario Building Code minimum | What it means on site |
|---|---|---|
| Clear opening area | 0.35 m² (3.8 sq ft) | Measured with the sash fully open — frame and sash are not counted |
| Smallest dimension | 380 mm (15 in) | A long, thin slot does not pass even if the area does |
| Operation | Openable from inside without tools, keys or special knowledge | No padlocked bars; security bars must have an interior quick-release |
| Window well clearance | 760 mm (30 in) in front of the window | Measured from the glass to the well wall; deeper wells need a way to climb out |
For a secondary suite in an existing house, the Code's Part 11 compliance alternatives add a practical limit: the bottom of the opening should be no more than 1.5 m (about 5 ft) above the floor, so an occupant can get out without a ladder. Casement windows are the usual answer in a basement because the whole sash swings clear; a slider or hopper has to be much larger to reach the same clear area.
Which rooms need one
- Every bedroom in the suite — including a den or office that could be used as a bedroom; inspectors look at the room, not the label on the drawing.
- Not required where the bedroom has a door that opens directly to the outside.
- Not required where the suite is protected by a sprinkler system (rare in houses, common in purpose-built units).
- Living rooms and kitchens are not required to have egress windows, though the suite as a whole still needs its separate entrance.
How an egress window is installed in a Toronto basement
- 1Locate services. We scan for the weeping tile, gas line, hydro feed and any buried drains along the wall before any digging.
- 2Excavate the well. The hole goes a few inches below the new sill so the well drain sits under the window, and wide enough for the 760 mm clearance plus the well itself.
- 3Cut the opening. Concrete or block is saw-cut to the new rough opening; in a poured wall over about 1.2 m wide, an engineered lintel is added above.
- 4Drain the well. A drain tied into the weeping tile (or a dry well where there is none) keeps the well from filling with water and leaking through the new window.
- 5Install and flash. The window is set, foamed, flashed and sealed; the well is set against the wall and back-filled with clear stone.
- 6Finish inside. Jamb extensions, trim and, in a suite, a fire-rated return if the window sits in a rated assembly.
What it costs
In Toronto and the GTA, a complete egress window — cutting the opening, the engineered lintel where needed, excavation, well, drain, the window itself and interior finishing — runs $2,500–$5,500 per window in 2026. The low end is a block wall with easy access and a standard well; the high end is a poured wall in a tight side yard where spoil leaves by hand. Add $800–$1,500 for a well cover, which is worth it for anything deeper than about 1 m.
Do egress windows at the same time as underpinning or waterproofing. The excavation and the drain tie-in are already open, and the engineering drawings already cover the wall — on its own, the same window costs 25–40% more.
Owner-Operator at Buildoreno with 25+ years of hands-on GTA construction experience. Last reviewed October 2026.