An egress window is a window large enough, and easy enough to open, that a person can escape through it and a firefighter can enter through it; in an emergency. Under the Ontario Building Code (OBC), bedrooms generally need a means of emergency escape, and in many homes (especially basement bedrooms) that means an egress window. This guide explains the concepts so you can plan intelligently but the OBC sets specific minimum dimensions and clearances that are amended over time, so always verify the current numbers with the City of Ottawa building department or a qualified professional before building or renovating.
Centennial Glass has installed windows across the Ottawa region since 1967, and egress questions come up constantly in basement renovation and bedroom conversion projects. Here is what homeowners need to understand.
What Makes a Window an “Egress” Window?
The Ontario Building Code’s escape-window requirements revolve around a few core concepts:
- Minimum unobstructed opening. The code specifies a minimum openable area the window must provide, along with minimum dimensions for the clear opening, so an adult can actually fit through. It is the *clear opening* that counts — not the size of the window frame. A large window with a small operable section can still fail egress.
- Openable without tools or special knowledge. The window must open from the inside without keys, tools, or hardware know-how. Security bars or screens that cannot be released from inside defeat egress.
- Maximum sill height considerations. The opening needs to be reachable; codes address how high the sill can be above the floor in practical terms.
- Window wells need clearance. For basement windows that open into a well, the code requires sufficient clearance in front of the window so the opening is actually usable, and awning-style windows that swing into the well are treated carefully for the same reason.
Again: the OBC attaches specific measurements to each of these concepts. Do not design to numbers from a blog post; ours or anyone else’s. Confirm current requirements with your building permit application or the City of Ottawa.
Where Egress Windows Are Required
The most common situations in Ottawa homes:
- Basement bedrooms. The classic case. Finishing a basement and adding a bedroom almost always triggers egress requirements and usually a building permit.
- Bedroom conversions. Turning a den, office, or other room into a legal bedroom means the room must meet bedroom requirements, including emergency escape.
- New additions. Bedrooms in additions must comply with the current code.
A bedroom without proper egress is more than a paperwork problem; it is a genuine life-safety issue and can complicate insurance claims and resale.
Choosing a Window Style That Achieves Egress
Different operating styles give up different amounts of clear opening for the same frame size, which makes style selection a practical egress decision:
- Casement windows crank open like a door, so nearly the entire window area becomes clear opening. They are often the easiest way to achieve egress from a compact frame; a major reason they are popular for basement bedrooms.
- Single-slider windows open to roughly half their width, so the overall window must be larger to deliver the same clear opening.
- Awning windows hinge at the top and swing outward; the hardware and opening geometry can limit the clear opening, and in a window well the swing itself can obstruct escape; they need careful assessment for egress use.
If you are weighing styles for a renovation, our guide to choosing the right window for your home compares the options more broadly.
Planning an Egress Window Project
A typical basement egress project involves more than the window: the opening may need enlarging (a structural change requiring a permit), the well may need excavating and lining, and drainage must be handled so the well does not collect water. The sequence that works:
- Confirm requirements first. Talk to the City of Ottawa about permits and the current OBC dimensions for your situation.
- Size the window to the code, not the code to the window. Choose a style and size that delivers the required clear opening with margin.
- Use professional installation. An egress window only works if it operates smoothly for decades; proper window installation with correct flashing, insulation, and hardware adjustment matters as much as the window itself.
Centennial Glass installs windows for both residential and commercial customers across the Ottawa region; roughly half our work is each and basement window installations are routine work for our crews:
“Kurt and Boris installed a new basement window for me. A lot of going inside and outside, up and down stairs. Very tidy, virtually no cleanup to do after they were done. Sealed the exterior very well with caulking. Beautiful job!”
— Kate C, 5★
FAQ: Egress Windows in Ontario
Does every bedroom need an egress window?
Bedrooms generally require a means of emergency escape under the OBC. In many homes that is an egress window, though specifics depend on the home’s layout and other exits. Verify your situation with the City of Ottawa or a qualified designer.
What are the exact OBC size requirements for egress windows?
The OBC specifies minimum openable area and dimension requirements, but the numbers can change with code updates and depend on your specific application so confirm current figures with the City of Ottawa building department or your permit reviewer rather than relying on summaries online.
Do I need a permit to add a basement egress window?
If you are enlarging the opening or adding a bedroom, a building permit is almost certainly required. Check with the City of Ottawa before starting work.
Which window style is best for basement egress?
Casement windows usually deliver the largest clear opening for a given frame size, which is why they dominate basement bedroom installations. Sliders work when the opening is wide enough; awning windows require careful evaluation.
Get Your Egress Window Done Right
From sizing the window to a clean, well-sealed installation, Centennial Glass brings 55+ years of Ottawa experience to every basement and bedroom window project; no job too large or too small. Call us at 613-738-9500 or contact Centennial Glass to discuss your project.