Computed from 1,966 recent building-permit filings in Seattle, WA — what people actually declared, not survey guesses.
✓ Verified from 1,966 recent building-permit filings in Seattle, WA
Every filing behind this range declared a residential renovation cost between $1,000 and $2,000,000 — outliers and commercial-scale projects are excluded. We only publish a range once at least 30 qualifying filings exist for a city/project combination; this one has 1,966.
Data refreshed September 2026
The short answer: a typical deck / decking build in Seattle costs around $30,000, with half of all projects landing between $12,000 and $100,000. If a quote falls well outside that range, it isn't automatically wrong — but it deserves an explanation you can understand.
Seattle's older housing stock (many homes pre-date modern energy codes) means insulation, moisture control and code-required upgrades surface often once a permit triggers inspection.
High year-round rainfall makes exterior work — roofing, decks, additions — weather-dependent, and correct flashing/moisture detailing matters more here than in drier climates.
The middle half of the published sample spans $12,000 to $100,000. That is a 293% spread around the median, so the details of your scope matter more than the label on the project.
Deck work can cover footings, framing, decking, stairs, railings, and finishes for the permitted footprint and height.
Difficult excavation, retaining walls, landscaping, drainage, lighting, and replacement of damaged existing structure may be outside the base scope.
This guide is based on 1,966 qualifying permit filings, not completed projects. Permit values reflect what applicants declared and can differ from the final paid cost.
Every figure on this page is computed from declared valuations on building permits filed with Seattle Department of Construction and Inspections (SDCI), published via the Seattle Open Data Portal. We report the 25th percentile, median and 75th percentile of 1,966 recent residential filings — never a single-point "average". Declared values are what applicants file, not final invoices, so treat the range as planning guidance rather than a quote. Full methodology →
The source dataset is maintained by Seattle Department of Construction and Inspections (SDCI). The published sample is the subset classified as residential, matched to this project type, and carrying a declared valuation from $1,000 to $2,000,000. The count above is the number of qualifying filings used for this city and project, not the number of homes or completed invoices.
Open the Seattle Open Data Portal datasetBased on 1,966 recent building-permit filings with Seattle Department of Construction and Inspections (SDCI), the median declared cost is $30,000. Half of all projects fall between $12,000 and $100,000.
No. Permit valuations are what applicants declare to Seattle Department of Construction and Inspections (SDCI) when filing, not final invoices — and Seattle Department of Construction and Inspections (SDCI) doesn't independently verify the declared value. Treat the range as planning guidance and a sanity-check against the quotes you receive, not a price to hold a contractor to.
Seattle's older housing stock (many homes pre-date modern energy codes) means insulation, moisture control and code-required upgrades surface often once a permit triggers inspection. That local variation is on top of the usual differences in size and specification, which is why we publish the 25th percentile, median and 75th percentile instead of a single misleading "average" — you can see where a quote sits in the real distribution.
Planning something else, or somewhere else? Request a city or project — requests decide what we ingest next.