How wide are interior doors supposed to be in Ontario houses?

Ontario's Building Code sets minimum door sizes for houses in Table 9.5.5.1. The required entrance door must be at least 810 mm wide. Most other rooms require at least 760 mm. A bathroom, water-closet room or shower room requires at least 610 mm.

Those are the door sizes the opening must accommodate, not clear-opening measurements.

What this means for an accessibility project

If you are widening a doorway to make it more usable, the Code minimum is a floor, not a target. What suits the person using the space is a question for them and whoever advises them. What you are asking a contractor to do is widen the rough opening and install a new, wider door.

A few things affect the price and the scope of that work. Published 2025-26 prices for widening a doorway in a non-load-bearing wall run about $500 to $2,500 per door. A doorway in a load-bearing wall costs more. The number of doors, the wall construction, and whether patching and repainting are included all show up in the quote.

On the permit side, the City of Ottawa's list includes "enlarging or relocating a window or door" as work that requires a building permit. The permit fee for alterations is $12.75 per $1,000 of construction value, with a minimum of $117 (City of Ottawa fee schedule, January 1, 2026). If the wall is load-bearing, that is also a structural alteration, which is on the permit list as well. The owner and the builder are equally responsible under the Building Code Act for making sure a permit is obtained when one is required.

A fair quote for this work should spell out the door size being installed, whether the wall is load-bearing, who pulls the permit, and what patching and finishing are included on both sides of the wall.

Ask the contractor to confirm in writing what the quote includes for patching, priming and painting after the frame goes in, so that cost does not appear as a surprise on the final invoice.