Basement Egress Windows: Toronto Fire Code Requirements Explained
Too Long; Didn't Read
- The Golden Rule: Every basement bedroom must have an egress point.
- The Magic Number: 0.35 m² (3.8 sq. ft.) of openable clear space.
- The Trap: Old "sliders" fail this code. You need "casements" or concrete cutting.
- Window Wells: Must have 550mm (22") clearance. Deep wells need a ladder.
Answer First: A Toronto basement window is legal for "Egress" only if the unobstructed opening is at least 0.35 m² (3.77 sq. ft.) AND no dimension is less than 380 mm (15 inches). It must open without keys or tools. For basement bedrooms, this is non-negotiable.
You finish your basement renovation. The drywall is up, the pot lights are on, and you list it on Airbnb.
Then the Fire Marshal shuts you down.
Why? Your bedroom window is 2 inches too narrow.
Basement egress is the #1 renovation failure point in Toronto. Here is how to pass inspection the first time.
The "Death Trap" Code
The Ontario Building Code (OBC) prioritizes survival over natural light. If the stairs collapse or block with smoke, a firefighter must fit through that window, or you must get out.
The Cheat Sheet (OBC 2025)
- 0.35 m² (3.8 sq. ft.): Minimum clear opening size. Not the glass size, the hole when open.
- 380 mm (15 in): Minimum width OR height. No "mail slot" windows allowed.
- No Tools: Openable from the inside without keys or screwdrivers.
The "Slider" Problem
Your existing basement windows are likely horizontal sliders.
- The Issue: Sliders block 50% of the opening even when fully open.
- The Math: To get 3.8 sq. ft. clear with a slider, the rough cutout must be massive—often 5 feet wide. Most Toronto basements lack this space.
The Solution: Casement Windows
Modern renovators use In-Swing or Out-Swing Casements.
- The Advantage: The sash swings entirely out of the way.
- The Result: You meet code with a smaller window, often fitting existing cutouts without concrete work.
Don't Forget the Hole (Window Wells)
Getting out of the window is step one. Getting up to the grass is step two.
- Clearance: Required 550 mm (22 in) clear space in front of the window.
- Depth: Wells deeper than 1 metre require permanent steps or a ladder.
- Drainage: Must tie into weeping tile to prevent flooding.
The Installix "Concrete Cut"
Sometimes, the foundation hole is simply too small.
We specialize in Concrete Cutting (Egress Expansion):
- Excavate: Dig down to the footing.
- Cut: Hydraulic diamond-saw allows enlarging the foundation opening.
- Support: Install new structural steel lintel.
- Install: Fit a fully compliant, oversized egress window.
Don't guess with fire code. If you are planning a basement bedroom, call us first. We bring the tape measure.