Markham's oldest pockets, including the heritage homes around Main Street Markham and Unionville, can still hide knob-and-tube wiring behind their walls. This ungrounded, early-1900s system was never designed for modern loads, and replacing it protects your home and often resolves issues with insurance and renovations.
Knob & Tube Wiring in Markham: local know-how
Knob-and-tube wiring runs ungrounded conductors through ceramic knobs and tubes, with no ground for today's three-prong appliances and electronics. In century homes near Markham Village and Unionville, decades of added loads, brittle insulation, and buried splices inside insulation create real fire risk. We assess the extent, then replace knob-and-tube with modern grounded NMD cable, install a proper panel and grounded outlets, and document the work. Many insurers in Ontario restrict or decline coverage on active knob-and-tube, and lenders may flag it, so a documented replacement frequently restores insurability. Rewiring is notifiable work, so we file the ESA permit and coordinate inspection throughout.
What's included
- Assessment of existing knob-and-tube and how much remains active
- Phased or whole-home rewiring to modern grounded wiring
- Updated outlets, switches and grounding
- Documentation insurers typically require
- Coordination of ESA permit and inspection
- Drywall-conscious approach to limit patching
Serving every part of Markham
We cover Unionville, Markham Village, Cornell, Cathedraltown and Berczy — and the rest of Markham. Call (289) 799-3802 for same-day and emergency availability.