Knob & tube
Knob & Tube Removal and Rewiring, Barrie
Staged rewiring for pre-1950 downtown and Allandale homes, with insurance certificates at each stage.
Knob and tube is the original residential wiring method: two separate conductors, run through porcelain tubes where they pass through framing and supported on porcelain knobs along it, with no ground and rubber-and-cloth insulation. In Barrie it turns up in the downtown core, along Blake and Codrington, and throughout the older parts of Allandale.
The real hazard is what happened after
Installed correctly and left alone, knob and tube was a reasonable system. Two things ruined it. First, the rubber insulation embrittles and falls off after seventy years, leaving bare conductor. Second, and more dangerously, the system was designed to shed heat into open air — and thousands of Ontario attics were later filled with blown-in insulation directly over live knob-and-tube runs. That is why most insurers treat its presence as a decline rather than a surcharge.
The third problem is the one we find on almost every job: sixty years of amateur extensions. Someone tapped a modern circuit into a knob-and-tube run to add a bedroom outlet, buried the splice in a wall cavity with no box, and it has been sitting there since 1974.
How we stage a rewire
A full rewire in one shot is expensive and disruptive, and most people cannot vacate a house for three weeks. So unless the whole place is being gutted, we stage it:
- Stage one — service and panel. New 200 amp service, new panel, and everything that will eventually be a new circuit gets its breaker space allocated now.
- Stage two — attic and second floor. This is where the insulation-over-conductor hazard lives, so it goes first. Usually the largest single stage.
- Stage three — main floor. Fished from below where there is a basement, which in most Barrie homes of this age there is.
- Stage four — basement, kitchen, bathrooms, and anything requiring GFCI or AFCI protection under current code.
Each stage is permitted and inspected separately, so you get an ESA Certificate of Acceptance as each one closes. That matters for insurance: you can often move from declined to conditional after stage two rather than waiting for the whole project.
What drives the price
Access, almost entirely. A house with a full unfinished basement, an accessible attic, and plaster that is already coming down for renovation is at the low end. A finished-basement, cathedral-ceiling, original-lath-and-plaster house is at the high end, because every run is a fishing problem and every fished run risks a repair to the plaster.
| Scenario | Typical Barrie cost |
|---|---|
| Full rewire during a gut renovation | $8,000–$12,000 |
| Staged rewire, occupied 1.5-storey, good access | $12,000–$16,000 |
| Staged rewire, finished basement and plaster throughout | $16,000–$20,000+ |
| Attic and second floor only (stage two alone) | $4,500–$7,000 |
| Drywall and plaster repair | Quoted separately — we patch, we do not finish or paint |
FAQ
Knob & tube — common questions
Can I insure a house with knob and tube?
It is difficult. Most major Ontario insurers decline outright; some specialty markets will write it at a significant surcharge with a remediation deadline attached. This is the main reason people rewire, and it is why we stage the work so the certificates arrive as early as possible.
Do I have to remove all of it?
To satisfy an insurer, effectively yes — abandoned-in-place conductor must be genuinely disconnected at both ends and is usually easier to remove than to prove dead. Where a run is truly inaccessible without demolition, we document it as de-energised and disconnected, which most insurers accept.
Will you have to tear my walls apart?
Less than you expect. Most runs are fished through existing cavities from the attic or basement, with small access holes at corners and where the framing blocks. Expect a few dozen patchable holes, not open walls — but budget for a plasterer.
Can I live in the house during the work?
Yes, on a staged rewire. That is the point of staging. You lose power to one area at a time and get it back the same day.
Talk to a Barrie electrician
Describe the problem over the phone. We can usually tell you whether it needs a truck today or can wait for a scheduled visit — and roughly what it costs — before anyone books anything.