Rewiring a house in Ottawa: how much of it, which walls open, and in what order

Whole house, one floor or a set of circuits

A rewire comes in three sizes. A whole-house rewire replaces every branch circuit from the panel out. A partial rewire takes one floor, one wing or the circuits that feed the problems, such as the kitchen or laundry. A renovation rewire replaces the wiring in rooms that are already open for a kitchen or a basement.

HomeStars calls updating part of the wiring less invasive and less costly than a full rewire. If a renovation is planned within a few years, say so: circuits run while the studs are bare take less labour.

What is in Ottawa walls, by build year

ESA dates knob-and-tube to the early 1900s through the 1940s, and aluminum branch wiring to houses built from the mid-1960s to the late 1970s. One Ottawa firm’s page describes a third kind between them: cloth- and paper-sheathed cable from the 1940s to the 1960s with no ground wire.

Wikipedia describes many Glebe homes as built in the early decades of the 20th century, and Hintonburg south of Wellington is almost entirely residential, in brick-veneer wood-frame houses from the 1910s and 1920s. Wikipedia notes that some Glebe houses were subdivided into apartments or rooming houses mid-century; say if yours was, and how many panels it has.

Plaster, drywall and the patching question

HomeStars adds $2,000–$5,000 when drywall has to be cut and patched, and lists lath and plaster and possible asbestos among the usual problems in older houses.

Plaster patching can fall to a separate trade. HomeStars’ Ottawa figures show plastering jobs at $750–$6,000, averaging $2,610, as of February 2022. Ask whether the electrician’s price ends at rough openings or includes closing them, and who paints.

Health Canada says asbestos carries no significant risk while undisturbed, and advises a professional test before renovating. Vermiculite insulation may contain it too.

Notification, rough-in, final

In Ontario, anyone you hire for electrical work must be a Licensed Electrical Contractor with a 7-digit ECRA/ESA number, and a general contractor has to bring one in. The contractor files the ESA notification before work starts. ESA lists a rough-in inspection, once branch circuits and outlet boxes are in and before insulation, vapour barrier or drywall covers them, and a final one. If the panel or service changes too, the utility disconnects power and ESA inspects before it is restored; see panel upgrades.

The City of Ottawa needs a building permit when walls are added or removed. Its permit exemptions do not apply to designated heritage buildings or houses in a Heritage District Overlay.

How the weeks usually run

1. Assessment visit at the panel and the boxes.
2. Written quote, then the ESA notification. If the service changes, Hydro Ottawa wants its request three to four weeks ahead.
3. Rough-in. One Ottawa firm says smaller homes or partial rewires take a few days, larger ones longer.
4. Rough-in inspection, then walls close and patching starts.
5. Final inspection and the Certificate of Acceptance.

What moves the price and what the quote should list

HomeStars puts a whole-home rewire at $8,000–$20,000 or more, and about $5–$17 per square foot. Size, floors, wall type and access set most of it. Materials on a full rewire add $500–$3,000 or more, and work around knob-and-tube or aluminum adds $50–$150 an hour.

Ontario’s guide for renovation businesses says a contract should list start and completion dates, sub-trades and who pays them, a deposit of 10% or less, and who cleans up. For a rewire, add the circuits covered, panel work, patching and the ESA fee. Work over $50 needs a written agreement, and the bill can exceed an estimate by 10% at most without a signed change.

Who you are dealing with

Ottawa Electric Desk passes your request to one independent local electrical contracting company. That company calls you back, assesses the house, prices the rewire and does the work.