2026-05-10 · MTC Renovations
Basement Egress Windows in Ontario: Code Basics for Hamilton Homeowners
If you’re finishing a basement in Hamilton or adding a bedroom below grade, egress windows aren’t optional — they’re a code requirement. The Ontario Building Code (OBC) sets specific minimum dimensions for windows in rooms used for sleeping, and failing to meet them affects both your permit approval and your insurance coverage if something ever goes wrong.
We install egress windows regularly as part of basement finishing and legal basement suite projects across Hamilton, Stoney Creek, and Dundas. Here’s what triggers the requirement and what the upgrade actually costs.
What Is an Egress Window?
An egress window is a window large enough for a person to climb through in an emergency. The OBC sets this requirement specifically for bedrooms and sleeping rooms in basements — the rationale being that a person who can’t exit through a door (fire, smoke, blocked exit) needs a second way out at grade level.
The requirement applies any time a basement room will be used as a sleeping space. If you’re finishing a basement with a rec room and a home office, egress may not be triggered. Add a bedroom to that layout and you need an egress-compliant window in that room.
OBC Minimum Dimensions
Under the Ontario Building Code (Section 9.9.10), a bedroom window must provide a minimum unobstructed opening of:
- Width: at least 550 mm (about 21.5 inches)
- Height: at least 900 mm (about 35.5 inches)
- Opening area: at least 0.35 m² (about 3.8 sq ft)
The window sill height matters too — it can’t be more than 1,000 mm (39 inches) above the finished floor, so the occupant can actually reach it.
Most standard basement hopper windows don’t meet these dimensions. Typical basement windows in Hamilton homes built before 1990 are too narrow, too short, or both. The upgrade usually means cutting a larger opening in the foundation wall and installing a larger window unit with a proper well outside.
When Does Hamilton Require a Permit?
Any time you’re cutting into a foundation wall — which is required to fit a larger egress window — you need a building permit from the City of Hamilton. The permit covers both the structural work (the opening in the foundation) and the window installation itself.
If you’re finishing a basement and adding bedrooms as part of a larger project, the egress windows are typically included in the same permit application. If you’re retrofitting just the windows in an already-finished basement, a standalone permit is required.
Don’t skip the permit. An unpermitted egress cut is visible the moment anyone looks at the exterior of your home. More practically, if you’re converting a basement to a rental unit, the city inspection process checks for egress compliance — and missing windows fail the inspection. We’ve seen deals fall apart at resale because unpermitted basement work came up during the buyer’s inspection.
What the Work Actually Involves
An egress window upgrade is more than swapping a window. The typical scope:
- Core cut or saw-cut in the foundation wall — enlarging the existing opening or cutting a new one. For poured concrete foundations (common in Hamilton homes post-1960), this requires a concrete saw. For block foundations (common in pre-1960 homes), it involves removing and reframing the block.
- Lintel installation — a structural header above the new opening to carry the foundation load around the window.
- Window well installation — if the grade is near or above the sill, a pre-formed or fabricated well is installed outside to allow the window to open and provide emergency egress space.
- New window unit — casement or awning styles work well for egress because they open outward and provide full clear opening.
- Interior framing and finishing — reframing the rough opening, insulating, drywalling.
Typical Costs in Hamilton (2026)
| Scope | Cost Range |
|---|---|
| Single egress window (poured concrete foundation) | $2,800 – $4,500 |
| Single egress window (block foundation) | $2,200 – $3,800 |
| Window well (basic pre-formed steel) | $400 – $800 |
| Window well (custom fabricated or deeper) | $900 – $2,000 |
| Permit (City of Hamilton) | $150 – $350 |
For a basement suite conversion requiring two or three egress windows, budget $7,000 – $14,000 depending on foundation type and site conditions.
Older Hamilton Homes: Watch for These
Hamilton has a large stock of pre-1960 homes in neighbourhoods like Stipley, Crown Point, and the East End. These homes often have rubble stone foundations or soft brick that require more careful cutting and additional structural reinforcement. Costs on these properties run 20 – 40% higher than poured concrete.
Some Hamilton neighbourhoods also have high water tables, which affects how deep you can install a window well and what drainage you need at the base. We assess grade and drainage as part of every egress window quote.
FAQ
Do all basement bedrooms in Ontario need egress windows?
Yes — any room designed or used as a sleeping room in a basement must meet OBC egress window requirements. This applies to new construction and to existing homes being renovated with the intent to create sleeping spaces. Guest rooms, in-law suites, and basement apartments all trigger the requirement.
Can an existing small window be modified to meet egress?
Sometimes. If the rough opening in the foundation is large enough, the window can be replaced with a compliant unit without enlarging the cut. More often in Hamilton’s older housing stock, the opening itself needs to be widened or heightened, which means structural work.
How long does the permit process take in Hamilton?
For a standalone egress window permit, Hamilton Building Division typically processes applications in 2 – 4 weeks. If the windows are part of a larger basement finishing permit, the timeline depends on the full project scope. We submit permits as soon as drawings are ready so waiting doesn’t hold up the job.
Whether you’re finishing a basement, creating a legal suite, or simply adding a bedroom below grade, egress windows are a non-negotiable part of doing it right. They’re also an investment that pays back — in safety, in resale, and in passing the inspection the first time.
Request a free estimate and we’ll assess your basement openings and let you know exactly what’s required.