How Much Does It Cost to Build a House in Seattle?

Rebuild, renovate, add on or build a DADU: what does each cost?

If you already own a house in Seattle, the choice is what to do with it: start over, rebuild the inside, add on, or put a second home in the backyard. The table lists our published starting prices at the Basic finish level and the typical time on site for each.

Source: our full home remodel, home addition and ADU pricing guides, updated October 2026. Design, engineering and permit fees are priced separately, and design and permits come before the time on site.

What does construction cost per square foot in Seattle?

We do not publish a per square foot price for a whole new house, because the lot sets too much of it. Our closest new construction figures come from additions and DADUs. Seattle design-build additions generally run $350 to $800 per square foot. A recent 1,000 sq ft DADU we contracted came to about $476 per sq ft for construction. Both figures cover construction only. Design, permit fees and utility connections are priced on top.

What does it cost to tear down and rebuild a house in Seattle?

A tear down and rebuild adds work that a remodel avoids: demolishing the old house, a new foundation, a new frame, roof, windows and siding, and new connections for water, sewer and power. The slope, the soil, the trees and the distance to the utilities change each of those lines.

In Seattle, the building permit comes from the Seattle Department of Construction and Inspections (SDCI). We look at the lot, the house and what you need from it, then price the rebuild in writing next to the renovation options. You compare real numbers for your address.

Often the house is worth keeping: a gut renovation replaces the systems and finishes and keeps the structure.

Is a gut renovation cheaper than rebuilding in Seattle?

A gut renovation starts at $500,000+ for a house of 2,000 sq ft or more, with every room taken to the studs. The Basic tier covers new electrical with the panel as required, new plumbing supply and drains, insulation and drywall throughout, a new kitchen and all baths, and floors, doors, trim and paint. It takes 9 to 14 months on site, after design and permits.

The finish level moves the number: Mid-Range starts at $650,000+ and adds a layout redesign, a heat pump or new HVAC and new windows where needed. Luxury starts at $850,000+ and Super-Luxury at $1,200,000+. Foundation repair and new square footage are not in these prices; we price them in writing when a house needs them.

Every tier, our own job prices and what each includes are in How Much Does a Full Home Remodel Cost?

When is a remodel with layout changes enough?

When the house is sound but the plan is wrong. Closed off rooms, a kitchen that seats nobody and a dark main floor are layout problems, and they are fixed by moving walls, which costs less than replacing the house. A remodel with layout changes starts at $300,000+ and takes 6 to 10 months on site. It covers opening walls with a new beam, opening the kitchen to the living areas, rebuilding two baths and new floors throughout.

The same idea works one room at a time. In Edmonds, our crew gutted a kitchen in 2021 and opened and reframed the wall to the dining room; that kitchen cost about $50,000. We check the structure at the first visit.

When is a whole home refresh enough?

A whole home refresh starts at $200,000+ for a 1,500 to 2,500 sq ft house and takes 4 to 7 months on site. Walls and plumbing stay where they are, and everything inside is new: the kitchen, two baths, floors, paint and lighting. A condo or townhome remodel starts at $125,000+.

Our Renton condo remodel is one example: one plank floor through every room, two refitted bathrooms, new lighting and updated plumbing and electrical. Doing the house in one project usually costs less than separate jobs over several years, because there is one permit, one demolition and one crew schedule. See how we plan it on Whole Home Remodeling Across the Greater Seattle Area.

How much does a DADU cost compared with a new house?

A detached DADU is a small new house of its own in the backyard. A 300 to 600 sq ft cottage starts at $325,000+ and takes 5 to 8 months on site. A 600 to 1,000 sq ft DADU with 2 bedrooms starts at $425,000+ and takes 6 to 10 months; in Bellevue that size range runs up to 1,200 sq ft.

A small unit costs more per square foot than a large one, because the kitchen, the bath and the utility connections cost about the same at any size. City fees, the King County sewer capacity charge, a new water meter or side sewer and long utility trenches are priced on top, for your lot. Design and permits usually take 4 to 9 months before construction.

Families choose a DADU when they want a second home on the lot for a parent, a grown child or guests while keeping the main house. Every ADU type is priced on Cost of an ADU or DADU in the Greater Seattle Area.

Is adding on cheaper than building a new house?

For more space, usually yes, because the house you have stays. A ground floor room addition starts at $150,000+, a primary suite at $250,000+ and a second story at $400,000+. Building out is usually cheaper per foot than building up. A second story needs the structure reinforced, a new stair and a roof rebuilt. All tiers are on Cost of a Home Addition in the Greater Seattle Area.

A single story house has the most ways to grow: Ranch House Addition Ideas and Plans compares building out, building up and finishing space you already have. Space you already have can also become a bedroom level. In a Seattle basement that a previous owner had mostly finished, we added a clothes closet, a storage closet and one plank floor through the level. It became a main bedroom level, completed in July 2024 for $120,000.

What raises the price of any of these options?

The same things push every option up, whether you rebuild, renovate or add on:

• Older home systems: galvanized pipe, knob and tube wiring and small electrical panels often need replacing once walls are open.
• Structural work: removing a load-bearing wall needs a beam, temporary shoring and engineering.
• Hidden conditions: rot, mold, asbestos or lead show up in older homes. We price repairs in writing before we fix them.
• Custom cabinetry and stone: they add cost and 8 to 12 weeks of lead time.
• Fees outside the build: design, structural engineering and permit fees are priced separately in the design phase, and appliances are not included.

How do you choose between rebuilding, renovating and a DADU?

Start with the condition of the house. If the foundation and frame are sound, renovating keeps the structure. Then the layout and the age of the systems decide between a refresh, layout changes or a gut renovation. If you need more room, an addition grows the main house and shares its kitchen and systems. If you want a separate home on the lot, a DADU gives it its own kitchen, bath and entrance. A rebuild makes sense when the structure itself is the problem.

At the walkthrough we check the panel, the plumbing and the structure, and our designer can draw the options in 3D before you decide. Each option you are weighing is priced in writing. We work across the city and the Eastside: see Home Remodeling Contractors in Seattle, WA.