How much does it cost to finish a basement in Seattle, WA?
Finishing a basement in Seattle, WA typically runs $30–$75 per square foot — most full basements land between $25,000 and $65,000. Adding a bathroom is the biggest extra, followed by egress windows, which building code requires for any basement bedroom. Moisture comes first: finishing over a damp basement is money buried twice.
What you can check yourself
- Fix water before finishes: watch the basement through a rainy season, or fix grading and gutters first — framing over seepage guarantees a redo.
- Ask whether the quote includes permits and an egress window if any room could be a bedroom — unpermitted basement 'bedrooms' hurt resale.
- Price the bathroom separately and honestly; it's often 25% of the whole budget.
Typical cost
Typical in Seattle, WA: basic finish $30–$50/sq ft; with a bathroom and better finishes $50–$75/sq ft. Egress window installation $3,000–$5,500 each.
When to call a pro
A licensed contractor with permits — a basement bedroom without egress is a code and safety issue, and unpermitted finished space usually has to be disclosed (or discounted) when you sell.
General Contractor pros in Seattle, WA
- ALTA CONSTRUCTION INCORPORATED · 300 PINE ST, SEATTLE, WA · 9512792762
- A2 BUILDS LLC · 526 1ST AVE S # 213, SEATTLE, WA · 2069208215
- 1029 SOUTH JACKSON STREET APTS INVESTORS LLC · 1029 S JACKSON ST, SEATTLE, WA · 2067286543
- ACMS NORTHWEST · 450 ALASKAN WAY S # 223, SEATTLE, WA · 5034905673
- 3 4 5 BUILDERS LLC · 516 29TH AVE, SEATTLE, WA · 2064236089
- ABBOTT CONSTRUCTION LLC · 3408 1ST AVE S # 101, SEATTLE, WA · 2064678500
- ACME CONSTRUCTION SUPPLY CO INC · 4747 1ST AVE S, SEATTLE, WA · 5038729805
- ACTION INDUSTRIES · 2417 10TH AVE E, SEATTLE, WA · 2063108463
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Data by Servik — verified local pros from official license records and public sources. Cost figures are typical ranges, not quotes; a pro's written estimate is the real number.