Same-size door swap in a New Edinburgh heritage home, call the City of Ottawa?

The heritage status of your property changes the answer here.

For most Ottawa homes, the City's list of projects not requiring a building permit includes "Replacing doors or windows (provided they are in the same size opening)". That exemption would cover a same-size interior door swap in an ordinary house.

The exception matters for your situation. The City states that designated heritage buildings and buildings within a heritage conservation district overlay are not subject to those exemptions. So the first thing to confirm is exactly how your property is designated. There are two possibilities:

• If your home is in a heritage conservation district, the district permit under the Ontario Heritage Act (s.42(1)) covers any part of the property other than the interior of a building, so an interior door is outside that permit; the City's building-permit exemption still does not apply, so confirm with the City.
• If your home is individually designated under Part IV of the Ontario Heritage Act, the designation by-law lists the heritage attributes the City is protecting. Some designation by-laws name interior features, including original doors, frames or trim. Any alteration likely to affect those attributes needs City approval under section 33 of the Act. You would need to read your specific by-law, or ask City heritage staff to walk you through it.

Either way, the building-permit exemption for a same-size door swap does not apply to your property, and the City is the only body that can tell you what approvals are actually needed before the work starts.

On the carpentry side, a same-size interior door replacement does not involve structural framing. The carpenter replaces the door within the existing rough opening, adjusts or replaces the frame if needed, and re-fits the casing. If the existing frame or casing is a protected heritage attribute, the carpenter should know that before anything is removed.

Start with City heritage staff rather than the building permit desk, because the heritage question determines which approvals come first and whether the door or its surround is a protected feature.