SEATTLE, WA – Dreaming of a backyard upgrade this year? Whether you’re picturing a peaceful family barbeque patio or a custom three-story deck with a pool and jacuzzi, understanding the true cost of building a deck in King County is the first step to making it a reality.
In this 2025 pricing guide, we break down what homeowners in Seattle, Bellevue, Kirkland, Tacoma, Redmond, and Mercer Island can expect to spend—and what factors impact those costs most.
What’s the Average Cost to Build a Deck in 2025?
In King County, average deck pricing ranges between $35 to $85 per square foot, depending on materials, elevation, layout complexity, and finish details.
Here’s a rough estimate of 2025 pricing:
- Basic wood deck (pressure-treated lumber): $18,000–$28,000 for 400 sq. ft.
- Mid-range composite deck: $25,000–$40,000
- Luxury hardwood or custom composite deck with features like pergolas, stairs, and detailed railing: $50,000+
- Multi-level, custom decks with built-in lighting, pool surrounds, and high-end finishes: $75,000–$150,000+
These figures include labor, materials, design, and permit handling.
What Impacts Deck Pricing the Most?
- Material Choice
- Wood remains the most affordable upfront. Cedar and pressure-treated lumber are popular across Tacoma and Redmond for their natural charm.
- Composite and PVC decking, widely used in Bellevue and Mercer Island, command higher prices but lower maintenance over time.
- Size & Elevation
Larger decks or those built on slopes with retaining walls or structural footings increase both material and labor costs. - Custom Features
Add-ons such as pergolas, custom stairs, unique railing, or built-in seating and lighting will raise the final total. Multi-tiered decks are especially popular in Kirkland’s hillside homes and cost more due to engineering and framing complexity. - Permits and Site Access
Some cities, like Seattle, have stricter permitting requirements and design review processes. Narrow access or sloped terrain can also increase construction time and cost.
How King County Decks Keeps Costs Clear and Honest
At King County Decks, we believe no homeowner should be left guessing. That’s why we offer:
- Transparent, upfront quoting with detailed breakdowns—no surprises
- Access to affordable materials as well as luxury upgrades based on your preferences
- A dedicated team capable of handling everything from simple patios to architect-designed, multi-level custom decks with stairs, pergolas, and hot tub framing
We’ve served homeowners from Redmond to Tacoma with precision and care, offering both deck repairs and full-scale new builds. Whether your vision is modest or majestic, we’ll guide you through every step of the process.
Long-Term Value: Maintenance vs. Longevity
Don’t forget to factor in long-term costs. Wood decks often need sealing or staining every 2–3 years. Composite decks, though pricier at installation, require less upkeep and tend to last 25–40 years without major repairs.
We always help our clients weigh these factors based on lifestyle, budget, and how they plan to use their space.
Ready to Build? Let’s Talk.
Building a deck is an investment—in your home and in your quality of life. Whether you live in Bellevue, Seattle, or anywhere in King County, the team at King County Decks is here to deliver expert craftsmanship with honest pricing and personalized service.
From functional upgrades to jaw-dropping backyard showpieces, we’re ready to turn your vision into reality.
Contact us today to schedule your free consultation.
