Remodeling an Older Seattle Home: What's Actually Behind the Walls

Seattle's single-family housing skews older than almost any West Coast city of its size. Those homes have wonderful bones and a specific set of things waiting behind the walls.

Knob-and-tube wiring

Common in homes built before roughly 1950. It isn't automatically dangerous when undisturbed and correctly used, but it has no ground, it's often been modified badly over the decades, and many insurers won't write a policy on it. If walls are open, replacing it is far cheaper then than later.

Plaster and lath, not drywall

Plaster is heavier, harder and more brittle than drywall. It's also better at sound and fire. Patching plaster well is a skill; matching texture is another. Contractors accustomed only to drywall often make a mess of it.

Floors that aren't level

Century-old houses settle. Floors slope, corners aren't square, and door openings aren't plumb. This matters enormously for tile and cabinetry — a level cabinet run in an unlevel room needs scribing and shimming, and large-format tile needs the floor floated flat first.

Undersized electrical service

Older homes commonly have 60 or 100 amp service. A modern kitchen with an induction range, dishwasher, microwave and lighting can exceed it. Panel upgrades are common and worth planning for in the budget rather than discovering mid-project.

Galvanized supply and cast iron waste

Galvanized pipe corrodes internally and restricts flow. Cast iron waste lines eventually fail. If the walls are open for a bathroom remodel, replacing these is dramatically cheaper than doing it as an emergency later.

Original woodwork is worth protecting

Old-growth fir trim and built-ins cannot be replicated with modern lumber. Protect it during construction. Where new trim is needed, matching the original profile — rather than substituting stock — is the difference between a remodel that looks right and one that looks patched.

Budget a real contingency

For a pre-1940 home, a meaningful contingency isn't pessimism, it's planning. Something will be found. A contractor who tells you otherwise hasn't opened enough old walls.

In the Puget Sound specifically

Much of the housing stock across Renton, Seattle, Kent, Tacoma and the Eastside predates 1980, and a large share of Seattle proper predates 1940. That age is what makes these homes worth renovating and also what makes the process less predictable than a new build.

Common questions