Knob and tube wiring: what it does to a Seattle purchase

6 min read · 6 sections

Every electrician's page will tell you knob and tube is a fire risk. That is true, and it is not what ends most transactions. What ends them is insurance: if a carrier will not write a policy on the house, your lender will not fund the loan, and the deal stops regardless of how anyone feels about the wiring.

The order the problem actually arrives in#

Knob and tube is early-twentieth-century wiring, and Seattle has a lot of housing stock old enough to still have some. Craftsman bungalows across Ballard, Wallingford, Greenwood and the Central District were wired this way when they were built.

When it turns up in an inspection, the conversation people expect is about safety and rewiring cost. The conversation that actually decides the outcome runs in a different order: your insurance carrier decides whether it will cover the home, your lender decides based on whether you can get insurance, and only then does anyone talk about what rewiring costs.

That order matters because it changes who you call first. Most buyers call an electrician for a quote. Call your insurance agent first — their answer determines whether the quote is even relevant.

The partial-rewire trap#

Very few older Seattle homes are still fully knob and tube. Most were partially updated at some point — a previous owner rewired the kitchen, added a panel, ran new circuits to the bedrooms — and left some original wiring in the walls or the attic.

Sellers describe this as "it's been updated." Insurers ask a narrower question: is any knob and tube still active. Those are not the same question, and the gap between them is where deals fall over.

So "partially rewired" is not an answer you can act on. What you need is which circuits are live, which are abandoned in place, and whether an electrician will put that in writing.

What to check before you write#

In this order. The first two are free and can be done before you spend anything on inspections.

1. Call your insurance agent with the addressBefore the electrician, before the inspection. Ask directly whether they will write a policy on a home with active knob and tube, and what they would need to change that answer. Some carriers decline outright, some surcharge, some require a licensed electrician's certification.
2. Ask your lender what they needFinancing usually follows insurance, but not always in the way you expect. Ask whether they require the wiring remediated before closing, or whether proof of insurance is enough. Get the answer before you negotiate, because it sets the boundary on what you can ask the seller for.
3. Read the listing and the disclosure for hedged language"Updated electrical" and "some knob and tube remains" describe the same house. Washington's Form 17 asks the seller about known conditions — read what is stated and note what is carefully not stated.
4. Get an electrician to scope it, not just price itA quote tells you a number. A scope tells you which circuits are still active, what is abandoned, and whether the work can be done without opening walls. The second one is what you negotiate from.
5. Ask whether the attic insulation is a factorKnob and tube was designed to shed heat into open air. Where later insulation has been laid over it, that is a specific hazard an inspector should call out, and it is common in homes that were retrofitted for efficiency without anyone checking the wiring first.
6. Treat published cost ranges with suspicionEstimates vary enormously — published figures run from around $5,000 for a small partial job to well past $20,000 for a full rewire, and Seattle homeowners report numbers at the high end. Access, house size, plaster versus drywall and how much remains all move it. Get two real quotes on the actual house rather than planning around a national average.

VERIFY BEFORE PUBLISHING — Insurance appetite, lender requirements and rewiring costs all move, and they differ between carriers as much as between houses. This page names the checks, not the current numbers. Confirm anything specific with your own carrier, lender and electrician.

How it gets negotiated#

Once you know the scope and whether you can insure the house, this becomes an ordinary negotiation with three usual outcomes.

The seller remediates before closing. Cleanest for you, slowest, and it depends on them having the time and the motivation. Worth asking for when the home has been sitting.

The seller credits you at closing. Common, and it suits a buyer who would rather choose their own electrician. Watch that the credit is sized against a real quote rather than a guess, and check your lender permits a credit that large.

You take it off the price and handle it yourself. Often the simplest, and the right answer when you were planning to open walls anyway.

What does not work is agreeing to a number before anyone has scoped the work. That is how a $6,000 credit meets a $20,000 job.

Is it worth walking away from?#

Usually not, on its own. Knob and tube is a known, quantifiable, fixable condition, and it is priced into a great many perfectly good Seattle houses. Buyers who rule out every home with original wiring rule out a large share of the older stock in the neighbourhoods they most want.

It is worth walking away when you cannot get a straight answer. If nobody will tell you which circuits are live, or an insurer will not commit, or the seller resists letting an electrician scope it, the problem is no longer the wiring — it is that you are being asked to price an unknown.

That distinction is the whole thing. A known cost is a negotiation. An unknown cost is a risk you are being handed for free.

Common questions#