Composite Decks in Kirkland & the Eastside
A composite deck on the Eastside costs $60 to $110 per square foot installed, depending on the board line, the height and the railing. Hans Construction builds composite decks from Trex, TimberTech and Fiberon on pressure-treated or steel framing, with the gapping, ventilation and fastening each manufacturer requires so the warranty stands.
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Why composite suits Northwest yards
Composite boards do not absorb water the way wood does, do not need staining, and do not rot. In a shaded Kirkland or Sammamish yard where a cedar deck stays damp from October to May, that difference decides whether the deck lasts eight years or twenty-five. The trade-offs are real too: composite costs more up front, gets warmer in direct sun, and shows a mildew film in deep shade that washes off but does come back. The Composite vs Cedar tool runs the numbers for your yard. Our Composite vs Cedar guide explains how each board ages in Puget Sound yards.
Board lines compared
| Line | Type | Look | Warranty (manufacturer) | Price band |
|---|---|---|---|---|
| Trex Enhance | Capped composite | Simple grain, limited colors | 25-year limited | Entry |
| Trex Select | Capped composite | Brushed grain | 35-year limited | Mid |
| Trex Transcend | Capped composite | Deep grain, wide palette | 50-year limited | Upper-mid |
| TimberTech Pro | Capped composite | Varied tones, scalloped or solid | 30-year limited | Mid |
| TimberTech Advanced PVC | Capped PVC | Realistic wood, cooler underfoot | 50-year limited | Premium |
| Fiberon Good Life / Sanctuary | Capped composite | Rustic to refined | 25 – 50-year limited | Entry to upper-mid |
Warranty terms belong to the manufacturer and depend on installation to their specification, which is why we follow it to the letter.
How we build a composite deck
- Layout and footings: post locations from the plan, concrete footings below the frost line on undisturbed soil.
- Ledger: house siding removed at the ledger line, flashing installed, ledger through-bolted or lagged per the city's detail.
- Framing: ground-contact pressure-treated lumber or steel joists at 12 inches on center for diagonal or wide boards, 16 inches for standard runs.
- Joist tape on every joist, beam and rim to stop water sitting on the framing.
- Boards with hidden clips or color-matched screws, end gaps and side gaps set to the manufacturer's temperature table.
- Fascia, railings and stairs.
- Final walkthrough and care instructions.
A 300-square-foot ground-level deck takes five to eight working days on site once materials are delivered.
Composite deck costs on the Eastside
| Deck | Installed range |
|---|---|
| 250 – 350 sq ft, ground level, entry composite, simple railing | $18,000 – $30,000 |
| 300 – 450 sq ft, under 6 ft high, mid-line boards, aluminum railing | $28,000 – $48,000 |
| 400 – 600 sq ft, premium PVC, picture-frame border, cable or glass rail | $45,000 – $85,000 |
Add 30% to 80% for second-story or hillside decks with tall posts and engineered bracing.
Design details worth paying for
- Picture-frame border: a contrasting perimeter board hides cut ends and makes the deck look finished.
- Breaker board: a board running across the field where lengths meet, instead of staggered butt joints.
- Wider boards in a shaded yard dry slower; standard widths with good airflow stay cleaner.
- Light-colored boards in full south sun stay noticeably cooler underfoot.
- Integrated stair lights and post-cap lights, wired before the boards go down.
Composite deck permits
Most Eastside cities and Seattle require a permit for a deck more than 30 inches above grade at any point, for any deck attached to the house in some jurisdictions, and for any deck carrying a roof or a hot tub. We prepare the framing plan, footing details and ledger detail the city asks for. The Deck Permit Checker tells you whether your deck needs one. Deck Permits on the Eastside Explained covers the submittal and review.
A composite deck we built
Composite deck questions
Does composite get slippery in the rain?
Capped composite has a textured surface that holds traction better than wet cedar with algae on it. Any deck gets slick under a film of moss or leaves, which is why we leave airflow and recommend a spring wash.
Will mold grow on composite?
In deep shade, a surface mildew film can form on any deck surface. On capped composite it washes off with a deck cleaner and a soft brush; it does not penetrate the board.
How hot does composite get in summer?
Dark composite in direct afternoon sun gets hot enough to notice barefoot. Lighter colors and PVC lines run cooler. In most Eastside yards, shade from trees and the house limits the problem to a few hours a day.
Can composite go over my existing deck framing?
Only if the framing is sound, spaced correctly for composite and level. Older cedar framing at 24 inches on center is too wide, and most framing under a worn-out deck has rot at the ledger.
How long does a composite deck last?
Twenty-five to fifty years for the boards, depending on the line. The framing under it is what decides the real lifespan, which is why we tape it and flash the ledger.
Do I need to seal or stain it?
No. Wash it once or twice a year. That is the main reason to choose it.
Tell us the size and the color you like. We will bring samples to the visit.