Why knob and tube needs replacing
Knob and tube wiring was installed in Ontario homes until roughly the 1940s. The wire itself isn't necessarily failing, but nearly a century later the problems stack up: brittle insulation, no ground, splices buried in insulation, and decades of amateur additions. Most insurers now decline or surcharge homes with active knob and tube.
- Full knob and tube removal or de-energizing
- Aluminum wiring remediation (1960s–70s homes)
- Grounded outlets throughout, AFCI-protected
- Room-by-room schedule while you live there
- Openings planned and left patch-ready
- Completion letter for your insurer + ESA certificate
How we rewire a lived-in house
We start in the basement and attic, where access is open, and run new home-run circuits up through walls from below and above. On the main floors, we open small, planned access points — usually along baseboards and at switch heights — rather than stripping plaster. Each day ends with power restored to the rooms you need.
Old cable is disconnected and, where reachable, removed. Where it's buried behind plaster and fully de-energized, it's abandoned in place, which ESA and insurers accept.
Aluminum wiring
Homes built roughly between the mid-1960s and late 1970s may have aluminum branch wiring. It isn't automatically unsafe, but connections can loosen and overheat over time. The fix is either full replacement or pigtailing with connectors approved for aluminum-to-copper — we'll inspect and recommend the right approach.
What it costs
| Scope | Typical range |
|---|---|
| Toronto semi or row house, full rewire | $12,000 – $22,000 |
| Detached 2-storey, full rewire | $18,000 – $35,000 |
| Partial (remaining live K&T circuits only) | $3,500 – $9,000 |
| Aluminum pigtailing, whole house | $1,800 – $4,000 |
Combining a rewire with a 200 A panel upgrade saves a second set of permits and a second power-off day — worth considering together.
Knob & tube replacement by city
Toronto · Etobicoke · East York · Markham · Whitby · Oshawa · Oakville
Questions
Can I get home insurance with knob and tube in Ontario?
Many insurers will not issue or renew a policy on a home with active knob and tube, and others add a surcharge or set a deadline for replacement. After we rewire, you receive the ESA Certificate of Acceptance and a completion letter to send them.
How long does knob and tube replacement take?
A typical Toronto semi takes one to two weeks; larger detached homes two to three. You can usually stay in the house — we restore power to occupied rooms at the end of each day.
Do you have to open all the walls?
No. We work from the basement and attic wherever possible and make small, planned access holes elsewhere. Most rooms need a few openings, not demolition.
Is it okay to leave old knob and tube in the walls?
Yes, if it's fully disconnected from power. De-energized knob and tube abandoned in place is accepted by ESA and insurers; the key is that none of it is live.
