Canadian building code question

What window requirements apply to bedrooms and egress in Canada?

Bedroom windows must meet minimum size requirements for natural light and, in many conditions, provide an egress opening for emergency escape. The required opening size, sill height, and operability depend on the building classification, the bedroom's location within the building, and provincial adoption.

Bedroom window requirements address two distinct code objectives: natural light for habitable rooms and emergency egress for life safety. These are separate provisions with different size and performance requirements. A window that meets the natural light requirement may not meet the egress opening requirement, and vice versa. The safest approach is to check both provisions independently for the applicable building classification and province.

What to check first

  • Natural light requirements set a minimum unobstructed glass area relative to the floor area of the room.
  • Egress window requirements set a minimum opening size and sill height for emergency escape, typically in bedrooms below the fourth storey.
  • Provincial adoption can change the egress window trigger, minimum opening dimensions, and exceptions for sprinklered buildings.

Jurisdiction notes

National baseline

Start with the NBC provisions covering natural light for habitable rooms and egress window requirements for bedrooms, including minimum opening dimensions and sill height.

Province and edition check

Confirm whether the province amends the egress window size, sill height, or the storey threshold above which egress windows are no longer required.

Project-specific variables

Building classification, bedroom location, storey level, sprinkler status, and window well conditions for below-grade bedrooms can all affect the applicable requirements.

Work through it in this order

  1. Confirm the building classification, bedroom storey level, and whether the building is sprinklered.
  2. Review the NBC natural light provisions for the minimum glass area required for habitable rooms.
  3. Review the NBC egress window provisions for minimum opening size, sill height, and the storey threshold where the requirement applies.
  4. Check provincial adoption for modified egress window dimensions, exceptions, and any additional requirements for below-grade bedrooms.

Common questions

Does every bedroom need an egress window?

Not necessarily. The egress window requirement typically applies to bedrooms below a certain storey level and may be exempted in sprinklered buildings depending on provincial adoption.

What is the minimum egress window opening size?

The code specifies minimum dimensions for the unobstructed opening, but the exact size depends on the code edition and provincial adoption. Verify the cited provision rather than relying on a general number.

Do basement bedrooms have additional window requirements?

Yes. Below-grade bedrooms typically require window wells that meet specific size and access conditions in addition to the egress opening requirement.