Can I add insulation if I still have knob and tube?

No, you should never add insulation around 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 operate in free air, allowing heat to dissipate naturally. When you surround these old wires with insulation, you trap heat that can cause the wire insulation to deteriorate and potentially ignite. The cloth and rubber insulation on knob and tube wiring is already brittle after 80-100 years, and adding thermal stress makes failure much more likely.

Insurance companies in Ontario are increasingly refusing coverage for homes with knob and tube wiring, especially when it's been covered with insulation. Even if your current insurer hasn't dropped you yet, they likely will when you renew or make any claims. Many insurers now require complete removal before providing coverage.

The Ontario Electrical Safety Code doesn't explicitly prohibit insulating around knob and tube, but ESA inspectors and insurance companies strongly discourage it due to fire risk. More importantly, if you're adding insulation as part of a renovation, you'll likely need to bring the electrical up to current code anyway, which means replacing the knob and tube.

Your safest and most cost-effective approach is to have the knob and tube wiring replaced before adding insulation. In Ottawa, knob and tube removal typically costs $400-800 per circuit, depending on accessibility. While this seems expensive upfront, it's much cheaper than dealing with a house fire or being unable to get insurance.

For a typical Ottawa home, complete knob and tube removal might cost $8,000-15,000, but you'll gain proper insulation capability, insurance coverage, and peace of mind. Many homeowners find that the energy savings from proper insulation help offset the electrical upgrade costs over time.

If you're planning to add insulation, get a free assessment from a licensed electrician first. We can identify which circuits need replacement and help you prioritize the work. Don't risk your family's safety by cutting corners on this critical upgrade.