Get Your Free Deck Cost Estimate
Answer four questions and get a King County–accurate price range in seconds. Permits included. No email required.
Deck Cost Estimator
King County 2025 pricing · Permits included · Takes 60 seconds
Your Estimated Range
Budget Estimate
$20,300
Basic finish, standard hardware
Typical Estimate
$24,500
Mid-grade materials, full warranty
Premium Estimate
$30,700
Top materials, 25–30 yr warranty
Estimates include King County permits ($300–$650), demo of existing deck where applicable, and standard project cleanup. Final price varies by lot conditions, HOA requirements, and material availability. Most projects land within 10% of the Typical Estimate.
Seattle Deck Cost by Material (2026)
Seattle pricing runs 15–25% above national averages due to higher labor rates, hillside lot complexity, and permit requirements. All figures below are installed cost in King County.
| Material | Cost per Sq Ft | 400 Sq Ft Project | Maintenance | Warranty |
|---|---|---|---|---|
| Cedar | $35–$55 | $14,000–$22,000 | Stain every 2–3 yrs | 15–20 yr lifespan |
| Composite | $50–$75 | $20,000–$30,000 | Clean twice yearly | 25-yr fade & stain |
| PVC | $60–$85 | $24,000–$34,000 | Rinse & done | Lifetime structural |
| Membrane | $80–$120 | $32,000–$48,000 | Inspect drains annually | Rooftop / over-structure |
All estimates include demo of existing deck, King County permits ($300–$650), and standard cleanup. Final price varies by lot grade, HOA requirements, and material availability.
Why Seattle Costs More
King County labor runs $65–$100/hr. Hillside lots, permit complexity, and material freight add 15–25% above national averages.
Deck Adds Home Value
A quality composite deck on a King County home typically returns 60–80% of cost at resale and accelerates sale timing in a competitive market.
Ways to Save
Book in fall or winter for better availability. Choose composite over PVC when view isn't a priority. Ground-level decks save 15–35% vs. hillside builds.
How Much Does a Deck Cost in Seattle?
In King County, expect to pay $19,000–$55,000+ for a professionally installed deck. Seattle deck costs run 15–25% above national averages. A 300 sq ft composite deck that costs $16,000 nationally typically runs $19,000–$22,000 here.
Why Seattle Costs More
- ▸Permit fees: King County building permits run $300–$650, required for all decks over 200 sq ft or 18” above grade
- ▸Labor rates: Seattle union-adjacent wages put skilled labor at $65–$100/hr vs. $45–$70/hr nationally
- ▸Material freight: West Coast port surcharges on composite decking add 6–12% over Midwest pricing
- ▸Hillside lots: Engineered foundations for view decks on steep terrain add $8,000–$18,000 to any project
Quick Cost Benchmarks
- ▸Entry-level cedar (200 sq ft): $14,000–$22,000
- ▸Mid composite (300 sq ft): $28,000–$42,000
- ▸Premium PVC (400 sq ft): $50,000–$70,000
- ▸Deck resurfacing only: $7,000–$16,000 if frame is sound
All figures include King County permit fees and standard site cleanup. Hillside engineering, custom railings, and demo of existing structure are itemized separately — see below.
Seattle Deck Cost by Material (Detailed)
All prices are installed cost for a 300–400 sq ft deck in King County, including permit. Ranges reflect grade selection, square footage, and project complexity.
Entry-level composite deck — clean, functional, $18,000–$28,000 installed range for 300–400 sq ft in King County.
| Material | Entry | Mid-Range | Premium |
|---|---|---|---|
| Pressure-Treated Pine | $12–$18K | $18–$28K | n/a |
| Western Red Cedar | $18–$28K | $25–$38K | $35–$50K |
| Mid Composite (Trex Select / TimberTech Terrain) | $22–$32K | $28–$42K | n/a |
| Premium Composite (Trex Transcend / TimberTech Vintage) | $32–$50K | $45–$65K | $60–$85K |
| PVC (AZEK / TimberTech Pro) | $38–$55K | $50–$70K | $65–$90K |
| Membrane (Vinyl) | $8–$15K | $15–$25K | $22–$35K |
Prices reflect 300–400 sq ft installed in King County including permit and standard cleanup. Hillside engineering, railings, and demo are not included — see add-ons section below.
Deck Cost by Square Footage — Seattle
Larger decks have a lower per-square-foot cost due to fixed costs (permit, mobilization, ledger attachment) spreading across more surface area. The 300 sq ft size is the most common in King County.
Premium multi-level build with cable railing — $45,000–$80,000 range, Trex Transcend or TimberTech Legacy boards.
| Size | Cedar | Mid Composite | Premium Composite |
|---|---|---|---|
| 200 sq ft | $14,000–$22,000 | $18,000–$26,000 | $26,000–$38,000 |
| 300 sq ft most common | $22,000–$35,000 | $28,000–$42,000 | $38,000–$55,000 |
| 400 sq ft | $28,000–$45,000 | $36,000–$55,000 | $48,000–$70,000 |
| 500+ sq ft | $35,000–$60,000 | $45,000–$70,000 | $60,000–$90,000+ |
Installed cost in King County including permit. Does not include hillside engineering, railings beyond basic aluminum, or existing deck demo.
Cost by Deck Configuration
The structural requirements of your lot matter as much as the material you choose. Here's how configuration affects total cost in the Seattle market.
Elevated hillside build — engineered post system adds $5,000–$18,000 to any deck on a slope.
Ground-Level Deck (under 18” above grade)
No structural engineering required in most King County jurisdictions. Simplest permit path.
Typical range: $18,000–$35,000
Elevated Deck (18–42” above grade)
Standard framing with footings. Most common configuration for Seattle-area homes with grade change from back door to yard.
Typical range: $22,000–$42,000
Hillside / View Deck (posts over 6 ft, engineered)
Common in Sammamish, Issaquah, Mercer Island, and Bellevue Hill neighborhoods. Requires stamped engineering drawings and extended post systems.
Add $8,000–$18,000 for engineering + extended posts
Rooftop / Membrane Deck
Vinyl membrane system over a living space or garage. Requires waterproofing layer, drain installation, and flashing. Common in urban Seattle and Bellevue.
Typical range: $15,000–$35,000 for 300–400 sq ft
Wraparound Deck
Corner framing complexity, multiple ledger connections, and longer railing runs add significant labor. Popular on craftsman homes in Kirkland and Bothell.
Add 40–60% over a standard rectangular deck of the same area
Deck Replacement (existing structure sound)
If the existing frame passes structural inspection — no rot at ledger, post bases, or beams — you can resurface over it and save significantly.
Save $8,000–$15,000 vs. full rebuild when frame passes inspection
What Drives Deck Cost Up
These additions are optional but frequently requested in Seattle. We price each as a separate line item so you can see exactly what you're choosing.
Built-In Benches
$800–$2,500Per bench section, includes fascia and framing integration
Attached Pergola
$8,000–$25,000Freestanding runs higher; custom cedar or aluminum options
Cable Railing (vs aluminum)
+$35–$55 per linear footStainless cable tensioned through steel or wood posts
Glass Railing
+$80–$120 per linear footFrameless tempered glass; popular for view decks
LED Step Lighting
$1,200–$3,500Low-voltage system wired to existing panel
Outdoor Kitchen Rough-In
$2,500–$6,000Gas, electrical, and water stubs only — does not include appliances
Demo of Existing Deck
$2,500–$6,000Size, material, and haul-away distance drive cost
Engineered Drawings (steep lots)
$1,200–$2,500Required for Norway Hill, Sammamish Plateau, and Mercer Island
Hidden Costs Homeowners Miss
We itemize every cost on your estimate. Here are the items that surprise homeowners who received a low-ball quote that didn't include them.
King County Building Permit
Always included as a line item in our estimates. Some contractors quote a low base price and add this at permit pull — ask before you sign.
Disposal & Haul-Away
Demo material from an existing deck must be hauled to a licensed transfer station. Varies by size of deck removed and haul distance.
Structural Hardware
Hidden fasteners (Cortex, Camo), post bases, joist hangers, ledger bolts, and beam connectors. This is real material cost — not included in $/sq ft board estimates.
Design Time
We design at the estimate stage at no charge. Some firms bill $500–$2,000 for CAD drawings before you've agreed to anything. Ask before you invite them out.
HOA Architectural Review
Submitting to your HOA ARC is typically free. Some associations require a professional drawing package — we include HOA-ready drawings as part of our permit set.
Should You Resurface or Rebuild?
This is the most common question we get from homeowners in Renton, Kent, and Federal Way with aging decks. The answer depends on frame condition — not how the deck looks on the surface.
Resurfacing Makes Sense When...
- ✓ Frame is under 15 years old
- ✓ No rot at ledger, post bases, or beam ends
- ✓ Deck passes structural inspection (we do this at estimate)
- ✓ Joists are pressure-treated and dry
- ✓ You want to upgrade from cedar to composite without a full rebuild
Cost: $7,000–$16,000
Full Rebuild Is Necessary When...
- ✗ Ledger shows rot, separation, or improper flashing
- ✗ Post bases have ground contact rot (common in PNW)
- ✗ Beams are sagging or checking
- ✗ Deck is over 20 years old and built with older PT standards
- ✗ You want to expand the footprint or change the configuration
Cost: $20,000–$55,000
Our Free Structural Inspection
Every estimate includes a complimentary structural walkthrough. We check ledger attachment, post base condition, beam and joist integrity, and code compliance. You'll know within 30 minutes of our visit whether a resurface or rebuild is the right call — and we'll show you exactly why.
Financing Your Deck Project
A quality deck is a long-term investment. Most homeowners fund it one of three ways — here's how they compare.
Our Lending Partners
6.9–12.9%
APR · 36–120 month terms
- ✓ Apply in minutes at estimate
- ✓ No equity required
- ✓ Decisions same day
HELOC
Prime +1–2%
Variable rate · 2–4 week setup
- ✓ Typically lowest rate option
- ✓ Interest may be tax-deductible
- ~ Requires home equity
Personal Loan
8–15%
APR · Fixed rate · Fast approval
- ✓ Approval in 1–3 days
- ✓ No equity required
- ~ Higher rate than HELOC
When Does Financing Make Sense?
Consider a $35,000 premium composite deck financed through our lending partner at 8.9% APR over 84 months — that's about $563/month. Compare that to a cedar deck at the same size: lower upfront cost, but add $400–$600 every 2 years for staining and sealing, plus the eventual full replacement cost in 15–20 years. Over a 25-year horizon, the composite financed option often costs less in total dollars — and eliminates maintenance weekends.
Deck Cost FAQ — Seattle
Do Seattle deck permits add a lot to the cost?expand_more
King County permits run $300–$650 for most residential decks. We pull the permit and include it as a line item on every estimate — it's never a surprise. The structural inspection that comes with the permit also protects you: a permitted deck is far easier to sell with later.
Is composite really worth the extra cost over cedar in the Pacific Northwest?expand_more
In most cases, yes. The PNW's wet winters and shaded lots accelerate cedar degradation. A quality cedar deck needs staining every 2 years and eventually boards replaced. Capped composite has a 25-year fade and stain warranty and resists the mold and moisture that shortens cedar's lifespan here. The break-even point is typically 8–12 years.
Can I get an accurate price over the phone?expand_more
We can give you a realistic ballpark, but the final price depends on lot grade, existing structure condition, and your material selection. Our free on-site estimate usually takes 45 minutes and gives you a firm quoted range — accurate enough to plan your budget.
How far in advance should I book a deck project in Seattle?expand_more
Spring and summer slots (April–August) book out 6–12 weeks ahead. For the most competitive pricing and fastest scheduling, we recommend booking in the fall or winter for a spring install. We honor quotes for 90 days.
Does my deck need a permit in King County?expand_more
Most do. A permit is required for any deck that is attached to the house, more than 200 sq ft, or elevated more than 18 inches above grade. Freestanding ground-level decks under 200 sq ft often qualify for a simple over-the-counter permit. We handle all permit filings as part of every project.
