Updated September 2026 · Typical installed prices for Seattle, Tacoma and Everett-area homes
Most Puget Sound homeowners pay $18,000 to $45,000 for a 300–400 sq ft composite deck. A typical project runs $75 – $130 per sq ft for composite, installed.
for a 300–400 sq ft composite deck
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Adjust the size and options to see a typical installed price for a Puget Sound home.
The budget option; needs yearly care in our climate.
Beautiful and naturally rot-resistant; regular sealing.
Low maintenance, won’t rot or splinter.
Roof or pergola for year-round use.
Composite costs more up front, less over its life.
Hillside and second-story decks need more structure.
Glass, cable and metal railings add cost.
Most decks over 30 inches high need a permit.
Ranges are typical installed prices for the Seattle–Tacoma–Everett area, checked against published local pricing (sources below). They’re for planning. Your written quote is the real number.
A 300 to 400 square foot composite deck commonly costs $18,000 to $45,000. Wood decks cost less up front.
Labor rates, permit fees, hillside lots and stainless hardware requirements.
It skips the yearly sealing a wood deck needs here, so the gap narrows over time.
Our typical range, $18,000–$45,000 for a 300–400 sq ft composite deck, sits inside what local contractors and cost publishers report. Their numbers differ because each prices a different scope, finish level or home size.
Footings, framing, composite decking, railings and stairs for a 300 to 400 sq ft deck.
Permits, demolishing an old deck, covers, lighting and steep-slope foundations.
Prices checked September 30, 2026 by Clearview Home Guide.
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