What Is an Egress Window? Ontario Rules and Basement Basics

An egress window is a window large enough and low enough for a person to climb out of in an emergency, such as a fire. In Ontario, the Building Code requires an exit route like this for bedrooms in many situations, especially basement bedrooms and legal second units, so egress windows matter for anyone finishing a basement or buying a home with a basement suite.

What makes a window an egress window?

Not every window qualifies. An egress window has to give a clear, easy way out. The Ontario Building Code sets specific requirements, which generally cover:

• Opening size: the window must open to a minimum clear area, with no single dimension too narrow.
• Operation: it must open from the inside without keys, tools or special knowledge.
• Height: the sill can’t be too high off the floor for a person to climb out.
• Window well: if the window opens into a well, the well needs enough room to move and climb out.

Exact measurements and exceptions are in the Building Code and can change. Always confirm current requirements with your municipality’s building department before you design or install.

Why egress windows matter

In a fire, smoke can block hallways and stairs within minutes. A basement bedroom without a second way out can be dangerous. Egress windows give people inside a route to escape and give firefighters a way in.

They also matter for legal and financial reasons:

• A basement bedroom without proper egress may not count as a legal bedroom.
• Legal second units need compliant egress as part of the permit process.
• Insurers and lenders may ask questions about unpermitted basement suites.

Egress windows and basement second units in Ontario

Ontario allows up to three residential units on most serviced urban lots, subject to local zoning. Many bungalow owners add a basement unit for rental income or family.

A legal second unit typically needs permits, fire separation between units, egress windows and a separate entrance or a compliant shared one. Brampton and many other GTA cities register second units, and inspectors check egress as part of the process.

If you’re shopping for a home with income potential, browse bungalows with a separate entrance or investor-friendly bungalows. Our guide on building a bungalow rental unit covers the bigger picture.

How an egress window is installed

Upgrading a small basement window is a real construction project. Here’s what it usually involves:

1. Permit: apply to the municipality with drawings showing the new opening.
2. Utility locates: have underground lines marked before digging.
3. Excavation: dig outside the foundation to make room for the window well.
4. Cutting the foundation: a contractor saw-cuts the concrete to the new size, sometimes adding a header for support.
5. Window install: a new window is set, sealed and flashed.
6. Window well and drainage: the well is installed with gravel and a drain so water doesn’t pool.
7. Inspection: the building inspector signs off on the work.

Costs vary widely depending on the foundation, the depth and the finish. Get at least three quotes from contractors who do this work regularly.

Types of egress windows

Window type	How it opens	Egress notes
Casement	Swings outward on a hinge	Opens almost fully, a popular choice
Sliding	Slides sideways	Only half the frame opens, so it needs a wider frame
Awning	Hinged at the top, opens outward	Often too restricted unless very large
Hopper	Hinged at the bottom, opens inward	Usually not suitable for egress

Your contractor and building department can confirm which style works for your opening.

What buyers should check

If a listing advertises basement bedrooms or a basement apartment, ask:

• Do the basement bedrooms have windows large enough to climb out of?
• Were the windows enlarged with a permit?
• Is the second unit registered or legal with the municipality?
• Are the window wells clear, drained and easy to climb out of?

A home inspector can flag concerns, but only the municipality can confirm whether a unit is legal. Your real estate lawyer can help you review permit records before closing.

Frequently asked questions

Do all basement bedrooms need an egress window in Ontario?

In many cases, yes. The Ontario Building Code requires bedrooms to have a way out, and a compliant window is the most common solution. Some exceptions exist, so check with your municipality.

Can I install an egress window myself?

It’s not a typical DIY job. It involves a permit, excavation and cutting the foundation, so most homeowners hire an experienced contractor.

Does an egress window add value to a home?

It can, because it allows a basement room to be used as a bedroom and supports a legal second unit. It also improves safety, which buyers and insurers notice.

The bottom line on egress windows

An egress window is a safety feature first. It also turns basement space into legal bedrooms and helps make a second unit possible.

If you’re finishing a basement, get permits and confirm requirements with your city. If you’re buying, check every basement bedroom window and ask about permits. Planning other window work? Our guide on when to replace windows can help.