Can you buy a house with knob-and-tube wiring in King County?

Where knob-and-tube still turns up in King County

Knob-and-tube was the standard way to wire a house from the late 1800s into roughly the 1930s. Two separate conductors run through the framing on small porcelain knobs and pass through joists inside porcelain tubes. There is no ground wire. The cloth and rubber insulation was designed to shed heat into open air.

In Seattle it’s most likely in the early houses of Wallingford, Queen Anne, Capitol Hill, Ballard, Ravenna, Beacon Hill, Columbia City, Mount Baker and the older blocks of West Seattle. Outside the city, look for it in the oldest houses near the historic downtowns of Renton, Kent and Issaquah.

Most of these houses have been partly rewired over the decades. A new panel went in, the kitchen got new circuits during a remodel, and the upstairs bedrooms stayed on the original wiring. “Updated electrical” in a listing can mean any of that.

How inspectors find it, and what they can’t see

A good inspector looks in the attic and the basement or crawlspace, where runs are often exposed. They’ll open the panel, look for cloth-covered conductors feeding into it, and test outlets. Two-prong outlets and ungrounded three-prong outlets are clues, though not proof.

Then the limits.

An inspector can’t open walls. They often can’t tell whether a visible run is live or long abandoned. Blown-in attic insulation can hide wiring completely, and a splice where old wire meets new may be tucked inside a wall cavity. So when a report says something like “recommend evaluation by a licensed electrician,” treat it as the start of the process and book that electrician right away.

Insulation deserves its own mention. Knob-and-tube relies on open air to stay cool, so insulation packed around live runs is something electricians and insurers take seriously. If the attic has been insulated over live runs, that’s a finding your electrician and your insurer will both care about.

Insurance and lending: questions to settle before you’re committed

Unless your purchase agreement has a separate insurance contingency, the inspection period is effectively your deadline for this answer, so call your insurance agent the same day the report arrives and ask directly:

• Will you write a policy on this house with active knob-and-tube wiring?
• Do you need a licensed electrician’s evaluation or letter first?
• Will you require it to be replaced, and by when?
• Does it change the premium or any coverage?
• Can the policy be bound in time for closing?

Carriers differ on this. Some decline. Others write the policy with conditions, or care more about what the electrician’s letter says than about the wiring’s age. If one company says no, ask your agent to try others before you decide anything.

Lending mostly follows insurance. Your lender needs proof of a homeowners policy to fund the loan, so the insurance answer is effectively the lending answer. Government-backed loans also ask the appraiser to note visible safety hazards, and exposed or damaged wiring can come up in that report. Ask your lender how they handle it before the inspection period ends.

Partial or full rewiring, and the electrical permit

The electrician’s evaluation should tell you which circuits are live, what condition the insulation is in, where the splices are, whether any runs sit under insulation, and whether the existing service can handle what you plan to add. A heat pump or a car charger can change the picture.

From there, the choices tend to fall into two groups.

A full rewire replaces every remaining knob-and-tube circuit and disconnects the old wiring. In houses with original lath and plaster, electricians usually fish new cable through the walls from the attic and basement and cut small openings where they have to, which then need patching and paint. It’s the cleanest outcome for insurance and resale, and it’s the most disruptive.

A partial rewire replaces the runs in the worst shape and any buried in insulation, then leaves the rest in service for now. It costs less and keeps more plaster intact. Some insurers accept it with an electrician’s letter. Others don’t.

Either way, the work needs an electrical permit. In Seattle, SDCI issues electrical permits and inspections. In much of the rest of the county, that’s the Washington State Department of Labor & Industries, though some cities run their own program, and your electrician will know which applies. Written estimates vary widely with the size of the house and how hard the walls are to get into, so get more than one if time allows.

Negotiating the fix inside your inspection period

Once you have the electrician’s scope and your insurer’s answer, you have real information to negotiate with. The options are the usual ones, each with its own catch:

• Ask the seller to do the work before closing. Write in who performs it (a licensed electrician), that it’s permitted, and that the final inspection is signed off before closing. You don’t choose the electrician or the scope beyond what you negotiate.
• Ask for a credit or a price reduction. You control the work, but it happens after you move in, and your lender may cap the credit a seller can give. Your insurer may also want it done by a set date.
• Accept the house as it is and plan the work yourself, once you know insurance is in place.
• Walk away within the contingency, if the answers aren’t ones you can live with.

How this fits with review periods, pre-inspections and offers without an inspection contingency is covered on the buying page. If you’re weighing a pre-inspection on an early 1900s house in a competitive situation, have an electrician walk it with the inspector.

Houses old enough for knob-and-tube are often old enough to raise a second question too: whether the house is bolted to its foundation. It’s worth asking both in the same week. And if old wiring has you rethinking the whole idea of an older house, a new townhome brings its own paperwork, which I explain in unit lot versus condominium townhomes.

Living with it for now: what an electrician may tell you

Electricians don’t all give the same advice. Some will say runs in good condition, lightly loaded and out of the insulation can stay in service for a while. Others recommend replacing all of it. Neither view is automatically wrong, and your insurer’s position often settles it.

If some of the old wiring stays, a few habits matter:

• Don’t add blown-in insulation or spray foam over any run until an electrician confirms it’s been disconnected. That comes up often in older Seattle houses when owners take on energy upgrades.
• Ask about GFCI protection for two-prong outlets, which an electrician can add without running a ground wire.
• Keep space heaters and other heavy loads off the old circuits.
• Keep the electrician’s letter, the permit and the final inspection with your house records. Your insurer and your eventual buyer will both ask.