Learn Alberta basement egress window sizes, building code requirements, and how to choose the right basement window dimensions for safety and compliance.
If you’re planning to renovate a basement in Alberta or add a legal bedroom, understanding basement window size, egress codes, and the right basement window dimensions is essential. Whether you’re a homeowner, landlord, or builder, safety and code compliance should be at the top of your list—especially when lives could depend on it.
This guide breaks down everything you need to know about basement egress window sizes, Alberta’s specific egress requirements, and how to select a compliant window without needing to cut concrete.
What Is an Egress Window?
The word egress means “to go out.” An egress window is a window that provides an emergency exit from a building. While typically installed in basements, egress windows are required in any room designated as a legal bedroom—particularly when that room doesn’t have direct access to a door that leads outside.
In the event of a fire or other emergency, a basement egress window can serve as a critical escape route when stairways or doors are blocked. Beyond safety, these windows also improve natural lighting and ventilation in lower-level spaces.
Why Basement Egress Windows Are So Important in Alberta
In Alberta, basement suites are a common feature in many homes, offering space for tenants, family members, or even rental income. But to legally designate a basement space as a bedroom or suite, it must meet Alberta Building Code standards—including window egress requirements.
Without a properly sized and installed egress window, your basement bedroom could be non-compliant, unsafe, and even uninsurable.
Alberta Basement Egress Window Code Requirements (2025 Update)
Under the National Building Code – 2019 Alberta Edition (NBC(AE)), specific standards must be met for a window to qualify as egress. According to Article 9.9.10.1, these include:
✅ Opening Mechanism:
- The window must open from the inside.
- It must not require tools, keys, or special knowledge.
- The window must be able to stay open without additional support.
✅ Minimum Clear Opening:
- Must provide an unobstructed open area of at least 0.35 m² (3.77 ft²).
- No dimension (height or width) can be less than 380 mm (15″).
✅ Window Wells:
If the egress window opens into a window well (which is common in basements), the following also applies:
- The well must provide at least 760 mm (2’ 6”) of clearance in front of the window.
- If the window sash swings outward, it must not block escape when fully open.
- The bottom of the window must be no more than 1 meter above the floor or ground, though this can be managed with a permanent step or bench.
Understanding Basement Window Dimensions
When planning to install or replace a basement window, it’s crucial to match both your needs and Alberta’s code.
Smallest Egress-Compliant Window Size in Alberta
To meet the minimum 0.35 m² opening requirement, you’ll need dimensions that allow sufficient clearance in both height and width. For example:
- Minimum Egress Dimensions:
- Height: 380 mm (15″)
- Width: ~925 mm (36.4″)
- Square Option:
- 592 mm x 592 mm (23.3″ x 23.3″) = exactly 0.35 m²
This represents the absolute minimum size needed to pass Alberta’s egress requirement. Smaller windows—even if they meet one dimension—will not qualify if they fall short in total area.
Common Basement Window Sizes (and Whether They Pass Egress)
| Window Size | Clear Opening (m²) | Egress-Compliant? |
|---|---|---|
| 600 mm x 600 mm | 0.36 | ✅ Yes |
| 400 mm x 900 mm | 0.36 | ✅ Yes |
| 380 mm x 880 mm | 0.33 | ❌ No – Too small |
| 500 mm x 700 mm | 0.35 | ✅ Yes |
| 300 mm x 1100 mm | 0.33 | ❌ No – One dimension under 380 mm |
If you’re unsure whether your basement window size qualifies, we can help assess it for free.
Basement Window Types That Work Well for Egress
Not all windows are ideal for egress—even if they meet size requirements. Functionality matters.
✅ Casement Windows (Best Choice)
Casement windows are hinged at the side and open outward with a crank. These are ideal for small window openings because the entire sash opens, allowing for a larger clear opening.
✅ Awning Windows (Use with Caution)
Awning windows are hinged at the top and swing out. While great for ventilation, they can obstruct escape if not sized properly. They’re typically not used for egress unless they are very large.
✅ Slider Windows
Horizontal sliders can be used for egress if the opening sash is large enough. The frame can reduce the total openable space, so these must be chosen carefully.
Basement Egress Window Wells in Alberta
When your window is below ground level, a window well is required. Alberta has strict guidelines:
Requirements:
- Minimum clearance from the window to the window well wall: 760 mm (2’6″)
- If the window opens outward, it must do so without restricting escape
- The maximum height of the window above the well floor: 1 meter (3’3”)
- If the well is deeper than 1.2 meters (4′), a ladder or steps must be built in
We can help determine if your current well setup meets these standards, or recommend compliant solutions.
What Happens If My Basement Window Doesn’t Meet Code?
Non-compliant windows could:
- Make your basement bedroom illegal
- Void your insurance coverage
- Create a major safety risk for occupants
- Block legal basement suite registration
For landlords and homeowners looking to create legal rental spaces or secondary suites, installing egress windows is not optional—it’s required by law.
Can I convert a non-egress window to egress?
Yes, but only if the existing opening meets size and accessibility requirements. Otherwise, excavation or modifications may be required—which we do not provide.
What if my window is just slightly too small?
Even minor deviations (e.g., a 0.33 m² opening instead of 0.35 m²) are non-compliant. Code enforcement officers often measure exact clearances.
Whether you’re building a basement suite, converting a guest room, or upgrading your old windows, understanding basement window egress is crucial. Alberta’s regulations are designed with safety in mind, and the right basement window size ensures peace of mind for you, your tenants, or your family.
Ready to Upgrade Your Basement Windows?
Contact Window Seal West today to book a free consultation. We’ll assess your basement window dimensions and help you find the right solution—built in Alberta, for Alberta.
