National baseline
The NBC specifies minimum unobstructed opening dimensions for egress windows in sleeping rooms and establishes window well requirements for below-grade conditions.
Canadian building code question
What are the building code requirements for window wells and egress windows in basements in Canada?
Basement bedrooms and habitable rooms typically require at least one egress window that meets minimum unobstructed opening dimensions. When the egress window is below grade, a window well must provide sufficient area and depth for emergency escape, and the well must include a permanent ladder or steps if the depth exceeds specified thresholds.
Basement egress window requirements are among the most frequently cited items during residential inspections. The rules cover minimum window opening size, window well dimensions, ladder requirements for deep wells, and how provincial adoption affects the specific thresholds. Getting these wrong can delay occupancy.
What to check first
- Every basement bedroom requires at least one egress window or door meeting minimum unobstructed opening dimensions specified in the code.
- Window wells must provide enough area for a person to escape and must include a permanent ladder or steps when the sill-to-grade depth exceeds code thresholds.
- Provincial adoption can change specific dimension thresholds. Confirm the adopted edition before relying on one set of numbers.
Jurisdiction notes
Provincial variation
Some provinces have adopted different minimum dimensions or additional requirements for window wells. Check the provincial code before finalizing window and well sizes.
Municipal enforcement
Inspectors frequently focus on egress window and window well compliance. Ensure measurements match the adopted code at inspection, not just at design.
Work through it in this order
- Confirm which basement rooms require egress windows under the adopted code.
- Verify minimum unobstructed opening dimensions for the egress window.
- Size the window well to meet minimum area and clearance requirements.
- Determine whether the well depth requires a permanent ladder or steps.
Common questions
What is the minimum size for a basement egress window?
The NBC specifies minimum unobstructed opening dimensions. The exact numbers depend on the adopted provincial edition. Do not assume one set of dimensions applies everywhere.
When is a ladder required in a window well?
Typically when the distance from the window sill to finished grade exceeds a specified depth threshold. The exact depth varies by provincial adoption.
Can a basement bathroom window count as the egress window?
Egress windows are required for sleeping rooms, not bathrooms. A bathroom window does not satisfy the egress requirement for an adjacent bedroom.