The King County Decks
Custom Deck Design and Build
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Custom Deck Design & Build in King County, WA
A custom deck is not a product off a shelf. It’s a structure designed specifically for your property, your home’s architecture, your family’s lifestyle, and the way you want to live outdoors in the Pacific Northwest. Every slope, every sightline, every material choice, every built-in feature — it all starts with listening carefully to how you actually use your outdoor space, and then designing and building something that serves that vision precisely.
King County Decks is King County’s custom deck design and build specialist. With 23+ years of residential construction experience through our parent company MJK Construction — including full custom home builds across Oregon and Washington — we bring structural depth, design capability, and finish-quality craftsmanship to every deck project we take on. From a clean ground-level platform to a three-story multi-level structure with integrated pools, hot tubs, pergolas, and lighting, we design and build it all from a single point of contact.
What Makes a Deck "Custom" — And Why It Matters
Most deck contractors offer variations of the same standard configurations — a rectangular platform, a few railing choices, a standard stair location. That works for straightforward lots with standard conditions. But King County’s terrain is rarely straightforward.
Hillside properties in Issaquah, Mercer Island, and Bellevue demand elevated structures engineered for steep grade changes. Waterfront homes in Seattle and Kirkland require designs that maximize water views while meeting setback requirements. Heavily treed properties throughout Sammamish and Woodinville need decks designed around root systems and canopy coverage. Townhomes in Seattle need rooftop platforms that account for existing roof structure and load capacity.
A truly custom deck design process addresses all of these conditions — site-specifically, structurally, and aesthetically — before a single board is cut. That’s the process King County Decks brings to every project.
Custom Deck Configurations We Build
Single-Level Ground-Level Decks: Simple, accessible decks that blend naturally with your yard and outdoor living space.
Elevated Single-Level Decks : Raised deck structures designed for hillside, split-level, and walkout basement homes.
Multi-Level Decks : Multiple connected deck levels that create separate zones for dining, lounging, and entertaining.
Wraparound Decks: Expansive decks extending around multiple sides of the home for added space and curb appeal.
Rooftop Decks : Custom rooftop outdoor living spaces built above garages, additions, or flat roof areas.
Pool & Spa Surround Decks : Durable, slip-resistant decks designed around pools, spas, and hot tub
Our Custom Deck Design & Build Process
Free On-Site Consultation
Custom Design & Detailed Estimate
Permits & Material Preparation
Foundation & Structural Framing
Decking, Railings & Features Installation
Final Inspection & Walkthrough
Why Homeowners Choose King County Decks for Custom Design & Build
With over 15 years of experience in residential construction through our founding company, MJK Construction, we bring the same level of precision and professionalism to every deck we build—now with a specialized focus on outdoor living.
From Bellevue to Seattle, Tacoma to Redmond, and across Kirkland and Mercer Island, homeowners trust King County Decks to turn ideas into functional, stunning outdoor extensions of their homes.
23+ Years of Experience
Founded by experienced builders with decades of residential construction expertise across countless successful projects.
Fully Licensed & Insured
Fully licensed, bonded, and insured throughout Washington State for complete homeowner confidence on every project.
ENERGY STAR® Certified Options
We provide ENERGY STAR® certified windows helping homeowners reduce monthly energy costs and maximize long-term savings.
Local King County Experts
Local King County specialists familiar with regional permits, building codes, and seasonal weather-related construction requirements.
Areas We Serve — Custom Deck Design & Build Across King County
Our custom deck design and build teams serve homeowners throughout King County and the greater Seattle metro area, including:
Seattle · Bellevue · Tacoma · Redmond · Kirkland · Mercer Island · Renton · Issaquah · Sammamish · Kent · Auburn · Federal Way · Burien · Shoreline · Bothell · Newcastle · Maple Valley · Woodinville
Frequently Asked Questions — Custom Deck Design & Build
Custom deck costs in King County typically range from $18,000 for a straightforward ground-level platform in pressure-treated lumber to $130,000+ for a large multi-level or wraparound composite deck with premium railings and built-in features. The primary cost drivers are deck size, decking surface material, structural complexity, site conditions, and included features. We provide accurate, itemized quotes based on your specific project — not ranges.
The construction phase of most custom deck projects takes 1–4 weeks depending on size and complexity. The total project timeline from first consultation to final inspection typically runs 6–14 weeks, with the permit review period being the most variable factor. Seattle, Bellevue, and other incorporated cities vary significantly in their permit review timelines.
In virtually all cases, yes. Any deck attached to a home, any deck over 200 square feet, and any deck over 30 inches above grade requires a building permit in King County. We handle the complete permitting process on every project that requires it — application, plan review, inspection scheduling, and final closeout.
A deck contractor typically builds from a standard set of configurations with limited design variation. A design-build firm like King County Decks develops a custom design for your specific site, handles all permitting documentation, and manages the full construction process under one roof. The result is a deck that was designed for your property rather than adapted from a template — and a single accountable relationship for the entire project.