Deck Building Cost in Seattle (2026)
Deck Building in Seattle runs about 18% above the national average. A typical 320 sq ft project starts around $5,660–$9,440 for pressure-treated wood. Estimate your exact Seattle project below.
Deck Building Cost Calculator
Adjust the details for an installed-cost range tailored to you.
Length × width of the deck surface. A 16×20 deck is 320 sq ft.
Ballpark estimate for planning — not a quote.
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Deck Building cost in Seattle by material
Installed cost for a typical 320 sq ft project in Seattle.
| Material | Per sq ft | Typical Seattle project |
|---|---|---|
| Pressure-treated wood | $17.7–$29.5 | $5,660 – $9,440 |
| Cedar / redwood | $29.5–$47.2 | $9,440 – $15,100 |
| Composite (Trex-style) | $35.4–$70.8 | $11,330 – $22,660 |
What affects your Seattle cost
- Decking material and railing style
- Height off the ground and stairs
- Footings, framing and permits
- Built-ins (benches, pergola, lighting)
- Local labor rates
Seattle deck building — FAQ
How much does deck building cost in Seattle?
In Seattle, a typical 320 sq ft deck building project runs about $5,660–$9,440 for pressure-treated wood, installed. That's about 18% above the national average — metro labor and permit costs in Seattle tend to run higher than the Washington state average. Use the calculator above for your exact size and material.
How much does deck building cost per sq ft in Seattle?
In Seattle, installed deck runs about $17.7–$70.8 per sq ft depending on material (pressure-treated wood $17.7–$29.5, cedar / redwood $29.5–$47.2, composite (trex-style) $35.4–$70.8). That's about 18% above the national average.
How much does it cost to build a deck in 2026?
A typical 320 sq ft deck runs about $5,000–$8,000 in pressure-treated wood, or $10,000–$19,000 in composite, installed. Size, height, railings and material drive the price — use the calculator for a localized estimate.
Is composite decking worth it?
Composite costs roughly 1.5–2× wood up front but eliminates staining/sealing and lasts 25–30+ years, so total cost of ownership is often lower. It's the popular choice for homeowners who don't want annual maintenance.
Deck Building cost across Washington
Seattle runs about 18% above the national average. See the full Washington breakdown and statewide averages.
← Deck Building cost in Washington