June, 2017
Inspection News and Views from the American Society of Home Inspectors

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Reporting on Painted Knob-and-Tube Wiring
I read with interest the article “Knob-and-Tube Wiring: A Revisit” by Alan Carson in the February issue of the Reporter, and it prompted me to share some of the issues that I’ve experienced when reporting on knob-and-tube wiring, particularly wiring that has been painted or placed with insulation. I’ve often found this painted knob-and-tube wiring in basements, in places where the joists and floor sheathing are exposed.

Here are some photos I’ve taken during recent inspections (at three different homes), along with my notes about how I reported on the issues:


Photo 1: In my written report for this home inspection, I described the condition and potential hazards of this situation in which wire is being insulated.

First, I explained to the client that knob-and-tube wiring should not be buried in plaster. Plaster acts as an insulator and because insulation does not allow for free movement of air, there is an increased risk that the wire will overheat. This creates a potential safety or fire hazard.

Second, I pointed out the charred sheathing above the light fixture, noting that I don’t know how or when that happened, or if the cause of the fire was ever fixed prior to my inspection. I explained that there would be an increased chance that the wiring could heat up in a location like this one, in which there is resistance (that is, a lamp and fixture) or a splice, especially when wiring has been painted or, in this case, painted over with plaster or a topping compound.

I recommended that my client hire a licensed electrician to examine this situation and make all the necessary repairs to ensure the safety of the wiring.


Photo2: It seems that the homeowners who decided to spray paint these basement joists were hoping to “brighten up” the basement. In the process, they painted over the wiring. The cloth insulation hardens from the paint, making it brittle and prone to cracking, which creates exposed, bare wire—a potential safety hazard.

Photo 3. Vertical view 
of a spliced wire.

Photo 3: This vertical view of knob-and-tube wiring shows a splice. Painted, spliced, bare wire weakens the contact, creating the potential to heat up and also creating a short, which again creates a potential safety hazard. Incidentally, part of the ceiling was not visible because it was covered with gypsum board and this was noted in the report.

Summary: One important thing I’ve learned while reporting on painted knob-and-tube wiring is this: As a home inspector, I must be confident in my own reporting and willing to defend my descriptions of findings. I mention this because two electricians have challenged my reporting of potential hazards related to knob-and-tube wiring, citing that there is nowhere in the National Electric Code that states that knob-and-tube wiring cannot be painted or that painted wiring presents a hazard. Incidentally, both electricians were contracted by the seller. Attempts also were made to pit me against another inspector (and that person’s findings) when the home was purchased by the seller.

When these challenges come up, we remind ourselves that we are performing a visual examination of the condition of the property based on our Standard of Practice, combined with our experience and base of knowledge.

Brian Giallombardo
ASHI Certified Home Inspector
Highland Heights, OH
email heartlandquality@roadrunner.com