clearing up the confusion about egress windows: basement in-law suites edition

There’s a lot of misunderstanding surrounding the requirements for egress windows in basement in-law suites. I’m here to shed some light on this and provide clarity based on the Ontario Building Code 2012 (OBC). Note that these citations apply specifically to Ontario, while the National Building Code (NBC), used in all provinces except British Columbia, Ontario and Quebec, may have different requirements.

Let’s break it down.

1. Bedroom Egress Window Requirement

Every floor that has a bedroom needs at least one window large enough to qualify as a Bedroom Egress Window unless there is a door leading directly outside on the same level. For the basement whether you have a legal in-law suite or just a bedroom, this rule applies. The window doesn’t need to be in the bedroom itself, but it must be somewhere on the floor.

Bedroom Egress for In-law Suites

2. Shared Entry: Secondary Egress Requirements

If the basement unit shares its entry with another unit, a secondary means of egress is required for each unit.

Additional Egress Requirements for Units with Shared Entrance

• For newly built homes (less than 5 years old): The secondary egress must meet one of the options outlined in the code, such as an additional exit to an exterior door, a public corridor, a fire escape, or a stairway that complies with specific height and clearance regulations.

Acceptable Exit Facilities

• For homes older than 5 years: The OBC allows for compliance alternatives (Part 11). In this case, a large window may serve as a secondary means of egress, but only if the building contains no more than two units. If the building has more than two units or the structure is newer, an exit that meets clause 9.9.7.2 of the OBC must be provided.

Alternative Exit Facilities for Homes That Are Older Than 5 Years

Key Takeaways:

• If your basement unit is in a walk-out basement, the exit door is sufficient, and no additional egress is required.

• If the basement unit has a dedicated entry that the other unit does not share, one Bedroom Egress Window (OBC 9.9.10) is necessary somewhere in the basement.

• If you have a shared entry between two units, a secondary egress must be provided. In buildings over five years old with no more than two units, a large window may serve this purpose under Part 11 (Clause C136). For all other cases, an exit door meeting OBC 9.9.7.2 is required.