Is it safe to add insulation over knob and tube wiring?

No, it is absolutely not safe to add insulation over knob and tube wiring. This creates a serious fire hazard that could put your family at risk and void your home insurance.

Knob and tube wiring was designed to dissipate heat through air circulation around the conductors. When you cover it with insulation, you trap that heat, causing the old cloth and rubber insulation around the wires to deteriorate even faster. This overheating can lead to arcing, sparking, and house fires. The wiring literally cannot cool itself properly when buried under insulation.

Insurance companies in Ontario are increasingly refusing coverage for homes with knob and tube wiring, especially when it's been covered with insulation. Many insurers now require complete removal before they'll provide a policy. Even if your current insurer hasn't dropped you yet, they likely will at renewal time if they discover insulated knob and tube during a claim investigation.

The Ontario Electrical Safety Code doesn't explicitly prohibit insulating over knob and tube, but it does require all electrical installations to be safe. ESA inspectors and insurance adjusters consider insulated knob and tube an unsafe condition. Most municipalities in the Ottawa area are also cracking down on this during home sales and renovations.

What you should do instead: Have the knob and tube wiring completely removed and replaced with modern Romex cable before adding any insulation. In Ottawa, knob and tube removal typically costs $400-800 per circuit, depending on accessibility. For a typical 1,500 square foot home, expect to budget $8,000-15,000 for complete rewiring.

Signs your knob and tube needs immediate attention: flickering lights, frequent blown fuses, outlets that don't work reliably, or any burning smells. If you're experiencing any of these symptoms, don't add insulation - call a licensed electrician immediately.

For a proper assessment of your knob and tube wiring and a quote for safe removal, contact Electrical Ottawa. We'll help you create a plan to upgrade your electrical system safely and maintain your insurance coverage.