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How Much Will Your Seattle Deck Cost?
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Your Estimate
$20,000 – $31,200
200–400 sqft · Composite / Trex
Ballpark estimate for Seattle-area projects. Final pricing depends on site conditions, design, and material availability.
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How Much Does a Deck Cost in Seattle?
Deck costs in Seattle typically run $15,000 to over $80,000depending on size, materials, and site complexity. The Pacific Northwest climate, Seattle’s steep lots, and permitting requirements all push costs above national averages — sometimes significantly.
Pressure-treated wood decks are the most budget-friendly, running $35–55/sqft installed. Cedar is a popular PNW choice at $55–85/sqft — naturally rot-resistant and beautiful in the rain. Composite decking (Trex, TimberTech, Fiberon) has become Seattle’s most popular choice for its low maintenance — expect $65–100/sqft. Hardwood/Ipeis the premium tier at $90–140/sqft — it’s extraordinarily durable and stunning, and can last 50+ years with minimal care.
Seattle’s hilly terrain is one of the biggest cost drivers not captured in national averages. A deck on a steep hillside lot in Wallingford, Leschi, or Capitol Hill can cost 25–50% more than the same deck on a flat Shoreline lot — deeper footings, more complex framing, and more difficult material staging all add up. Our calculator accounts for this with the site complexity multiplier.
Seattle building permitsadd $500–1,200 to most deck projects and are required for the vast majority of decks in the city. The permit process through SDCI (Seattle’s Department of Construction & Inspections) currently takes 4–8 weeks. We handle permitting for all our clients.
For a medium-sized composite deck (around 300 sqft) on a standard lot, budget $22,000–$36,000 all-in. Add a pergola, railing upgrade, and outdoor lighting, and a complete outdoor living space typically runs $38,000–$60,000.