How long does it take to rewire a 1920s semi-detached in High Park including the ESA inspection?

A full rewire of a 1920s High Park semi-detached typically takes 5–10 working days for the electrical work itself, plus another 3–14 days for the ESA inspection to be scheduled and completed — so plan for 2–4 weeks from start to certificate of inspection.

The wide range comes down to a few key variables specific to older Toronto semis: how much of the original knob-and-tube wiring is still active, whether the home has had decades of amateur additions spliced onto the K&T (extremely common in High Park and Annex-area homes), the condition of the plaster and lath walls, and whether the service entrance and meter base need upgrading at the same time.

What the Work Actually Involves

A 1920s semi in High Park is almost certainly running on knob-and-tube wiring — two-conductor ungrounded circuits with cloth insulation that has been deteriorating for 80–100 years. The rewire involves pulling all of that out and replacing it with modern NMD90 copper wiring, a new 200A panel (replacing the original fuse box), grounded outlets throughout, GFCI protection in bathrooms, kitchen, garage, and outdoors, and AFCI breakers on all bedroom circuits as required by the Ontario Electrical Safety Code.

The biggest time variable in a High Park semi is wall access. Electricians typically work through existing openings — outlet boxes, switch boxes, light fixture locations, attic access, and basement ceiling — to fish new NMD90 wire through walls without opening every surface. In a home with original plaster and lath, this fishing process is painstaking. If the walls are already open due to a renovation (which is the ideal time to rewire), the job moves significantly faster. A 1,200–1,500 sq ft semi with good attic and basement access might be done in 5–6 days. A tighter job with finished plaster throughout and limited access points can stretch to 8–10 days.

The ESA Permit and Inspection Timeline

Your electrician applies for the ESA permit before starting work — this is non-negotiable in Ontario. The permit fee for a full rewire typically runs $200–$400 based on the number of circuits and devices. Once the work is complete, the electrician notifies the ESA for inspection. In Toronto, ESA inspectors are generally booking 3–7 business days out during slower periods, but during the spring and fall renovation rush (April–June and September–November), waits can stretch to 10–14 days. If the inspector finds deficiencies — a missed GFCI location, an improperly supported cable run, a labelling issue on the panel — the electrician corrects them and schedules a re-inspection, adding another 3–7 days to the timeline.

Keep the certificate of inspection permanently in your home records. It is your proof that the work was done to code, and it matters enormously at resale and for insurance purposes.

GTA-Specific Considerations for High Park Semis

High Park and the surrounding streets (Roncesvalles, Parkdale, Bloor West Village) have some of the densest concentrations of pre-war housing stock in the GTA. A few things to plan for specifically:

Insurance pressure is real. Many Ontario insurers now require knob-and-tube removal as a condition of coverage or renewal. If your insurer has flagged this, get the rewire done before your renewal date — don't let coverage lapse.

Service entrance condition. Most 1920s semis still have the original overhead service entrance and 60A or 100A meter base. A full rewire almost always makes sense to pair with a service upgrade to 200A, which requires Toronto Hydro to disconnect and reconnect the overhead service. That coordination adds 1–3 days to the overall timeline and costs an additional $800–$1,500 for the Toronto Hydro work order, on top of the electrician's service entrance work.

Shared walls. In a semi-detached, some circuits may run through the shared party wall. A good electrician will map this carefully before pulling wire — you don't want to disturb your neighbour's wiring on the other side.

Budget. For a 1,200–1,500 sq ft High Park semi, expect $12,000–$20,000 for a complete rewire including panel upgrade. If the service entrance also needs replacement, add $2,000–$3,500. Get at least two quotes and confirm each electrician is licensed (verify at esasafe.com) and carries WSIB coverage.

Toronto Electrical Repair can match you with licensed electricians experienced in pre-war Toronto rewires — find local professionals through the Toronto Construction Network directory at torontoconstructionnetwork.com/directory?trade=electrical.