Shoreline Knob and Tube replaces knob-and-tube wiring, and the early cable that followed it, in homes across Shoreline, WA. The city’s older houses fall into two groups: a small number built before 1940, where porcelain knobs and tubes may still carry live circuits, and a far larger group from the 1940s and 1950s wired with cloth-braided cable that usually has no ground wire. Every job we take on starts by working out which of those systems is really behind the walls.
From there the work is replacing the circuits that need it with grounded cable, routing that cable through attics, crawlspaces and a few planned openings in plaster, and buying the electrical permit from Washington L&I so an inspector sees the new wiring before anything is closed up. We also help buyers and sellers when a home inspection report flags old wiring partway through a sale.
Builders began phasing knob and tube out in the 1930s, so in Shoreline it turns up mainly in the roughly 1,100 homes from before 1940 and in some from the following decade. Its two separate conductors run on ceramic knobs along framing and through porcelain tubes bored into joists, with no ground. We trace which runs are still energized and what outlets, lights or later additions they feed, then replace the live circuits with new grounded cable. Dead wire we can reach safely in the attic or crawlspace can come out during the same job rather than being left for the next inspector to puzzle over.
Cloth-covered and ungrounded wiring in 1940s and 1950s homes
Shoreline grew fastest in the early 1950s, and the decade left nearly 5,800 homes that still stand. Wiring from that period is usually sheathed cable under a cotton-braid jacket, and until the early 1960s most of it had no grounding conductor, which is why two-prong outlets are so common here. Some circuits can be made safer with GFCI protection, which the electrical code allows on ungrounded outlets; kitchens, bathrooms, laundry areas and anything powering computers often make a stronger case for new grounded circuits. We decide circuit by circuit instead of assuming the whole house needs one answer.
Rewiring behind plaster walls
Plaster was the usual wall finish in houses built up to the 1930s and 1940s, and fishing cable through it takes more care than drywall. We reach as many rooms as we can from the attic above and the crawlspace or basement below, cutting small openings only where a wire has no other way through, such as at a top plate or behind a switch. The quote states who opens each wall, who patches it and whether a plasterer is needed, and openings stay uncovered until the L&I inspector has seen the new wiring.
Old wiring flagged during a home sale
A home inspector’s report is visual, so a line about knob and tube or old wiring often raises more questions than it answers. We can test which circuits are live, write a replacement scope that buyer and seller can negotiate from, and check the electrical permits on record for the address in L&I’s online lookup, which covers permits bought since January 2020. Work done before then, or without a permit, will not appear there.
Panel and circuit capacity after rewiring
New branch wiring sometimes exposes a limit in the equipment feeding it: a screw-in fuse panel, a small main breaker, or too few spaces for the extra circuits a kitchen or bathroom now needs. Where insulation is added around knob and tube that stays, Washington’s rule requires those circuits to be on breakers or Type S fuses sized for the wire. We look at the panel and service during the survey and raise any limit we find, without assuming every rewire needs a panel upgrade.
From the first questions to a defined scope
How a Shoreline rewiring project works
01
Wiring survey
We start at the panel and in the attic, crawlspace or basement, identifying knob and tube, braided cable and later wiring. The survey notes which runs are live, where old and new wiring are spliced together, and how easily each wall can be reached.
02
Written scope
The findings become a plain document: circuits to be replaced, dead runs worth pulling out, the walls likely to need an opening, who closes those openings, and what the permit will cover. It doubles as the paper a buyer, seller or insurer may ask to read.
03
Permit, inspection and closing up
L&I issues the permit ahead of the first cut. New cable goes in, the state inspector looks at it while walls and ceilings are still open, and only after that visit do patches, trim and insulation go back.
How old is the wiring in a Shoreline home?
Census estimates for 2020 to 2024 count about 25,300 homes in Shoreline. Roughly one in nine was built before 1950, and nearly a quarter more went up during the 1950s, when this stretch north of Seattle was among the region’s fastest-growing areas, long before Shoreline incorporated in 1995. The census tracts with the highest share of pre-1950 homes sit around Richmond Beach, Briarcrest, Parkwood and North City.
As a rough guide, houses from before about 1940 are the likeliest to have had knob and tube, houses from the 1940s to the early 1960s usually have braided cable without a ground, and later homes have plastic-sheathed grounded cable. Additions, partial rewires and remodels blur those lines, so the year a house was built suggests what is in the walls but cannot confirm it.
Electrical permits in Shoreline go through L&I
Shoreline has no electrical permit office of its own. For addresses in the city, Washington’s Department of Labor & Industries (L&I) sells the electrical permit and sends the inspector, the same arrangement that applies in Lake Forest Park and Edmonds. The permit is the responsibility of whoever does the electrical work and must be in place before starting, and the inspection is requested while the wiring is still exposed.
Work is inspected under the electrical code edition in force when the permit is issued, and Washington moves to a newer edition at the end of 2026. Past permits for an address can be searched in L&I’s public lookup, which holds records for permits purchased from 2020 on.
Local project planning
Areas served around Shoreline
From Richmond Beach to North City, Shoreline Knob and Tube covers homes across Shoreline, WA, and next door in Lake Forest Park and Edmonds. Owners in Mountlake Terrace, Kenmore and Woodway can ask as well, and we confirm coverage for each address; bear in mind that Mountlake Terrace runs its own electrical permit program instead of L&I.
Frequently asked questions
Does a 1950s Shoreline house have knob and tube?
Usually not, though it is possible. Knob and tube was being phased out of new construction from the 1930s, so a house built in the 1950s more often has braided sheathed cable with no ground wire. An older structure that was enlarged in the 1950s can still hide knob and tube in its original rooms. Only an electrician looking at the wiring itself can tell you which you have.
Can insulation be added over knob and tube in Washington?
Yes, but Washington attaches conditions. WAC 296-46B-394 lets loose or rolled insulation surround existing knob and tube only after a licensed electrical contractor has examined it and given L&I a written statement that it is sound. The material has to be Class I for flame spread, foam is ruled out entirely, and breakers or Type S fuses matched to the old wire must protect each of those circuits. Any repair or extension gets inspected. Replacing the active knob and tube before insulating takes those circuits out of the rule.
Are two-prong outlets a reason to rewire?
Not on their own. A two-prong outlet means that circuit has no equipment ground, which is typical of both knob and tube and early sheathed cable. The electrical code lets an ungrounded outlet be replaced with a GFCI outlet, or with a three-prong outlet protected by a GFCI, as long as it is labeled “No Equipment Ground”. That protects people from shock but gives surge protectors and electronics no ground. Whether a circuit gets GFCI protection or new cable depends on its condition and what it powers.
Will my insurer accept the house after a rewire?
We can’t answer for an insurer, because each company sets its own rules on older wiring. Ask yours in writing what it needs to see, such as an electrician’s evaluation or proof that the old circuits were replaced. For work permitted through L&I, the permit and inspection result can be looked up by address on L&I’s website.
Your next step
Request a quote
Is the house from the 1920s, the 1950s or somewhere between? Has anyone seen porcelain knobs in the attic, fabric-jacketed cable at the panel, or two-slot outlets upstairs? Is a closing date approaching? Answers to those, plus the street address for the permit jurisdiction, give us a head start. We'll get back to you soon with an estimate or any questions we have. Estimates are free and there's no obligation.
