What Is the Minimum Ceiling Height in Ontario?

A habitable room is a space used for living, sleeping, eating, or cooking. Under OBC Part 9, the minimum ceiling height in habitable rooms is typically 2,300 mm measured from the finished floor to the finished ceiling. This applies to new construction and most substantial renovations.

Basement rooms used as living space must meet the same minimum height unless specific suite provisions apply. Low existing basements are a frequent barrier to legal secondary suites — measure after accounting for finished floor buildup and ceiling finishes.

Bathrooms, laundry rooms, and closets may have reduced minimum heights in some configurations. These spaces are not primary living areas but still must allow safe use and door swing clearance.

Existing houses undergoing renovation may have different triggers than new construction. Adding a secondary suite or changing the use of a space often requires current code minimums even if the original construction predates them — verify with your building department rather than assuming grandfathering.

New construction must meet current Part 9 dimensions throughout. Sloped ceilings in attics and rooms with cathedral ceilings must meet minimum height at the centre and within prescribed distances from walls.

Beams, ducts, bulkheads, and structural members may encroach below the minimum ceiling height within limits. OBC Section 9.5.2. sets headroom requirements in exits and under obstructions — encroachments cannot reduce height below allowed thresholds in walking paths or over required floor area percentages.

A habitable room is defined by its use, not just its label. Calling a 2,100 mm basement space a 'storage room' while using it as a bedroom does not exempt it from ceiling height and egress rules.