Short answer
Before closing on a Seattle fixer-upper, get a contractor's walkthrough alongside the inspection and price the six items that actually move the budget: foundation and drainage, the sewer line, electrical service, plumbing supply, roof, and asbestos or lead. Together they can add $50,000 to $250,000 that no cosmetic estimate will show you.
---
Why cosmetic estimates mislead on old Seattle houses
Walk through a tired 1926 bungalow in Ballard and it's easy to price the visible work: kitchen, two baths, floors, paint. Call it $200,000 and you have a number.
Then you close, open a wall, and find knob-and-tube. And a sewer line with root intrusion. And no insulation. And the crawlspace is damp because there's no perimeter drain and the grade slopes toward the house.
None of those were visible on the walkthrough. All of them are common in a housing stock where a large share of the inventory in the older neighborhoods predates 1960.
The six items to price before you close
1. Foundation and drainage — $5,000 to $80,000+
What to look for: horizontal or stair-step cracks in the foundation wall, doors that won't close square, a floor that slopes noticeably, efflorescence or staining on basement walls, standing water in the crawlspace, grade sloping toward the house.
What it costs: regrading and downspout extensions, $2,000–$8,000. A perimeter drain, $10,000–$25,000. Foundation replacement or underpinning, $40,000–$150,000+.
Seattle-specific: a lot of the city sits on glacial till and sloped ground, and many pre-1950 foundations are unreinforced concrete. Seismic retrofit — bolting the house to the foundation, adding shear — is a $5,000–$25,000 item that's worth doing during a remodel.
2. The sewer line — $6,000 to $30,000
Get a **sewer scope**. It costs a couple hundred dollars and it is the single highest-value inspection on an older Seattle house.
Pre-1950 side sewers are often clay tile or Orangeburg (a bituminized fiber pipe used mid-century that fails by deforming). Root intrusion is extremely common in neighborhoods with mature street trees — most of the older ones.
Spot repair, $6,000–$12,000. Full replacement, $12,000–$30,000, more if it runs under a driveway, a mature tree, or the street.
3. Electrical service and wiring — $3,000 to $30,000
Look at the panel. A 100-amp service is common in mid-century Seattle homes and is inadequate for a modern kitchen plus a heat pump plus an EV charger. Look in the basement and attic for knob-and-tube: individual cloth-covered conductors on ceramic knobs and tubes.
Panel upgrade to 200 amp, $3,000–$8,000. Service upgrade involving Seattle City Light, more. Whole-house rewire, $15,000–$30,000+ — and it means opening walls.
Also relevant: some insurers won't write a policy on a house with active knob-and-tube, and some lenders care. Ask your agent before you're under contract.
4. Plumbing supply — $8,000 to $25,000
Galvanized steel supply was standard in Seattle into the 1950s. It corrodes from the inside; low water pressure at the fixtures is the classic sign, along with rusty water after the house has sat.
Whole-house repipe in PEX or copper, $8,000–$25,000 depending on size and access.
5. Roof — $12,000 to $45,000
Ask the age. Composition shingle in this climate typically gives 20–30 years, and moss shortens it. Look for cupping, granule loss in the gutters, and any sag in the ridge line.
Re-roof, $12,000–$25,000 typical; more with multiple layers to tear off, a complex roof, or cedar.
6. Asbestos and lead — $2,000 to $40,000
Asbestos may be present in sheet flooring and its mastic, joint compound, pipe and duct insulation, and some siding in homes into the late 1970s. Lead paint is likely in anything pre-1978.
Testing, a few hundred dollars. Abatement is a licensed, contained scope: a small flooring abatement might be $2,000–$6,000; a whole-house scope with pipe insulation and multiple flooring layers can reach $20,000–$40,000.
This is not optional to know about. It affects both cost and schedule, and it has to be handled before demolition.
The six items, at a glance
