Custom deck building in Seattle. Trex, TimberTech composite and natural wood decks. Expert design and construction with a 10-year workmanship warranty.
A well-built deck extends your living space outdoors and adds real value to your home. In the Pacific Northwest, where we enjoy months of mild, beautiful weather from late spring through early fall, a quality deck becomes one of the most-used spaces in your home: morning coffee, weekend barbecues, evening gatherings, or simply a quiet spot to enjoy the view.
K Single Corp designs and builds custom decks across King, Snohomish, and Pierce County. Since 2007, we’ve built hundreds of decks for homeowners throughout the Puget Sound region, from compact urban decks in West Seattle to expansive multi-level structures overlooking the water in Edmonds and Mukilteo.
If there’s one region where composite decking makes the most sense, it’s the Pacific Northwest. Our climate is tough on outdoor wood: 8+ months of rain, persistent moisture, limited winter sun, and mild temperatures that promote mold and mildew growth. Natural wood decks in Western Washington require constant maintenance, and many homeowners eventually get tired of the annual stain-and-seal routine.
Composite decking eliminates that cycle. Premium composites from Trex and TimberTech are engineered to resist moisture absorption, mold growth, fading, staining, and insect damage. They don’t splinter, crack, warp, or rot, even after years of PNW weather.
Trex. We install the full Trex product line, including Trex Transcend (premium), Trex Select (mid-range), and Trex Enhance (value). Trex Transcend offers the most realistic wood-grain appearance, the deepest color palette, and the best performance warranties. All Trex products are made from 95% recycled materials.
TimberTech. TimberTech’s Azek line (capped polymer) and Advanced PVC products are the pinnacle of composite decking. Azek decking is moisture-proof to the core, so it will not absorb water even if the cap is scratched. TimberTech also offers the PRO Legacy and Reserve lines in capped composite for a range of budgets.
For homeowners who prefer the warmth and authenticity of real wood, we build decks using premium cedar and pressure-treated lumber. Cedar is a Pacific Northwest native that offers natural beauty, natural resistance to insects, and a warm, rich tone that many homeowners love. Pressure-treated lumber provides a more affordable option with chemical protection against rot and insects.
The honest truth about wood decks in the PNW: they require regular maintenance. Cedar decks need staining or sealing every 1-2 years to maintain their appearance and resist moisture. Pressure-treated decks need similar maintenance after the initial drying period. If you’re willing to commit to the upkeep, a natural wood deck is a beautiful thing. If you’d rather spend weekends enjoying your deck instead of maintaining it, composite is the way to go.
Every deck project starts with a conversation about how you want to use the space. From there, we follow a systematic process:
Design Consultation. We meet at your home to discuss your vision, measure the space, evaluate site conditions (grade, access, soil), and talk through material options. We’ll help you think through layout, traffic flow, stair placement, and features like built-in benches, planters, or pergolas.
Plans & Permits. We prepare structural plans that meet code requirements, submit permit applications, and handle all communication with the building department. Deck permits in King County, Snohomish County, and Pierce County require structural calculations for footings, beams, joists, and ledger connections, and we take care of all of it.
Site Preparation. We excavate for footings and pour concrete piers to support the deck structure. Proper footings are critical. They must extend below the frost line and be sized for the loads they carry. In the Puget Sound area, we typically pour footings 18-24 inches deep depending on the jurisdiction.
Framing. We build the structural framework using pressure-treated lumber for all ground-contact and structural members. The ledger board (where the deck attaches to the house) is installed with proper flashing and waterproof membrane. This detail is critical for preventing water intrusion into your home’s wall structure.
Decking & Railing. We install the decking boards with proper gapping for expansion and drainage, followed by railings, stairs, and any custom features. For composite decking, we use hidden fastener systems that give a clean, screw-free surface.
Final Inspection & Walkthrough. We schedule the required building inspection, walk you through the completed deck, and activate your 10-year workmanship warranty.
Beyond the basic deck platform, we build custom features that make your outdoor space truly yours:
Every deck we build is engineered for our climate. That means corrosion-resistant hardware, proper moisture management, adequate ventilation under the deck, and construction techniques that account for the realities of building outdoors in Western Washington. We back every project with our 10-year workmanship warranty, in addition to the manufacturer’s material warranty on the decking products.
We build decks throughout King County, Snohomish County, and Pierce County, including Seattle, Bellevue, Kirkland, Renton, Burien, Federal Way, Tacoma, Everett, and all surrounding communities.
Call K Single Corp at (206) 659-4349 for a free deck consultation and estimate.
Every deck we build meets or exceeds current building codes for structural requirements, railing height, and fastener spacing. We use pressure-treated framing with stainless steel hardware that won't corrode in PNW conditions.
Choose from premium composite decking (Trex, TimberTech) for minimal maintenance or natural wood (cedar, pressure-treated) for a classic look. We'll help you pick the right material for your budget and lifestyle.
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Free estimates with no obligation. We respond within one business day.
Real work on real homes across the Puget Sound.
Maple Valley
300 sq ft composite deck, covered pergola structure with polycarbonate roofing, built-in counter and grill space, composite railing, electrical for lighting and outlets.
Issaquah
Engineered footings on slope, pressure-treated frame, TimberTech composite decking in Mahogany, cable railing system, built-in bench, LED post cap lights, code-compliant guardrails.
From first call to final walkthrough. Here's how we work.
We inspect your roof, discuss your needs, and provide a detailed, no-obligation estimate, typically within 48 hours.
You receive a clear, itemized quote with material options, timeline, and warranty details. No hidden costs.
Our experienced crew handles your project with care: quality materials, clean worksite, and daily progress updates.
We walk the completed project with you, ensure everything meets our standards, and activate your 10-year workmanship warranty.
We offer payment plans to fit your budget. Ask about financing options during your free estimate.
Composite decking (Trex, TimberTech) is made from a blend of recycled wood fibers and plastic polymers. It resists rot, insects, and moisture damage without staining, sealing, or painting, making it ideal for the wet PNW climate. Natural wood decking (cedar, pressure-treated lumber) costs less upfront but requires annual maintenance to prevent rot and weathering. Composite has a higher initial cost but a much lower lifetime cost when you factor in years of staining and repairs.
Deck costs vary significantly based on size, material, height, and complexity. A basic 300 sq ft pressure-treated wood deck typically runs $8,000-$15,000. The same deck in Trex or TimberTech composite ranges from $15,000-$30,000. Multi-level decks, elevated decks requiring significant structural framing, built-in seating, and covered structures add to the cost. We provide detailed, itemized estimates during your free consultation.
In most cases, yes. Decks over 30 inches above grade, attached to the house, or over 200 square feet typically require a building permit in King, Snohomish, and Pierce County jurisdictions. Specific requirements vary by city. Seattle, Bellevue, Kirkland, and other municipalities each have their own thresholds and processes. We handle all permit applications, structural plans, and inspections for every deck we build.
A standard single-level deck (200-400 sq ft) typically takes 1-2 weeks from start to finish, including footing excavation, framing, decking installation, railing, and stairs. Larger or multi-level decks with pergolas, built-in features, or complex layouts may take 2-4 weeks. We provide a detailed timeline during the planning phase and keep you updated throughout construction.
Building decks in Western Washington requires specific techniques to manage moisture. We use proper joist spacing for drainage, install composite or stainless steel hardware that won't corrode, slope the deck surface slightly away from the house for water runoff, and ensure proper ventilation beneath the deck. For ledger board connections (where the deck attaches to the house), we use flashing and waterproof membranes to prevent moisture intrusion into the wall structure.
We primarily install Trex and TimberTech, both premium composite brands with excellent warranties and track records. Trex Transcend and TimberTech Azek are top-tier product lines with superior fade, stain, and scratch resistance. Both offer realistic wood-grain textures and a wide range of colors. The best choice depends on your color preferences, budget, and desired aesthetic. We can show you samples during your consultation.
Premium composite decking from Trex and TimberTech carries 25-year to limited lifetime structural warranties and 25-year fade and stain warranties. In practice, composite decking lasts 30-50+ years with minimal maintenance, requiring just periodic cleaning with soap and water. Compare that to natural wood, which typically needs refinishing every 1-2 years and may need board replacement within 10-15 years in the PNW climate.
Get a free, detailed estimate for your decks project. We respond within one business day.