Composite deck cost in Seattle, WA
Local estimate from BLS wage data and BEA price levels. Reviewed Nov 4, 2026.
- Typical range (300 sq ft)
- $14,100 – $28,300
- Per sq ft
- $47 – $94
- before permit
- Versus US midpoint
- +17%
- US $18,100
- Rank of 300 metros
- #14
- 1 = most expensive
A composite deck in Seattle, WA usually costs $14,100 to $28,300 for 300 sq ft. That works out to about $47 to $94 per sq ft before permits. Compared with the national midpoint that is $3,150 more. Carpenters earn a median of $36.74 an hour in the Seattle area, 26% above the US median of $29.12.
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Estimated cost for 300 sq ft in Seattle, WA, standard level
$18,400 to $24,100
About $61 to $80 per sq ft before permits. Labor is about 64% of the bill.
| Part | Low | High |
|---|---|---|
| Materials | $6,500 | $8,500 |
| Labor | $11,800 | $15,500 |
| Permits and fees | $90 | $130 |
| Total | $18,400 | $24,100 |
Cost breakdown for 300 sq ft in Seattle, WA
| Part of the job | Low | Midpoint | High | Share |
|---|---|---|---|---|
| Materials | $5,000 | $7,500 | $10,000 | 35% |
| Labor | $9,100 | $13,600 | $18,200 | 64% |
| Permits and fees | $55 | $110 | $170 | 1% |
| Total | $14,100 | $21,200 | $28,300 | 100% |
What is behind the Seattle number
The wage side of the estimate leans on carpenters, who do 80% of the hours on a typical job. Their local median is $36.74 an hour. Add the other trades involved and the blended wage index for Seattle is 1.26 (US = 1.00), which puts labor at 64% of the total.
Materials are scaled with BEA's regional price parity for goods. Seattle is at 104.0 against 100 for the US, so a materials line of $7,200 nationally becomes $7,500 here (midpoint, 300 sq ft). Permits follow the all-items index of 111.1: $55 to $170.
Specs and site conditions that change a Seattle bid
Labor
Labor for composite is $24-$48 per sq ft, higher than wood because the boards need extra parts and more careful assembly.
Drainage
Ground-level decks over poorly draining yards may need $1,000-$4,000 of drainage work first.
Engineering
Large or complex decks may need a structural engineer at $100-$220 an hour to get a permit.
What local crews earn in Seattle
The labor line is built from BLS wage data, one trade at a time. This job draws on 2 trades. We compare each trade's local median with the US median, weight the ratios by how much of the job each trade does, and apply the blend to the national labor cost. For Seattle the blend is 1.26.
Carpenters (47-2031), 80% of the weighting: a median of $36.74 an hour, 26% above the US median of $29.12. The middle half of them earn between $30.64 and $47.93 an hour. About 14,970 work in the metro. That is 71.8 per 10,000 jobs, compared with 43.1 nationally, which suggests plenty of local crews to bid.
For construction laborers (47-2061, weighted 20%) the local median is $28.72 an hour, which is 27% above the national $22.66. The middle half of them earn between $23.67 and $37.03 an hour. BLS counts 13,040 of them working in the area, 62.5 for every 10,000 jobs (US: 70.5), so the local bench is about average.
A quick sensitivity check: moving the lead trade (carpenters) from the median to the 75th percentile wage adds about $3,300 to the midpoint estimate; the 25th percentile takes off about $1,800. That is a swing of roughly 8.5% to 15.6% of the total, which is useful for judging whether a bid reflects wages or something else, such as scope or margin.
Seattle-Tacoma-Bellevue has 2,086,210 jobs in total (BLS, May 2025), ranking 13th by size among the 300 metros on this site.
| Trade | Weight | 25th pct | Median | 75th pct | US median | Ratio | Level used |
|---|---|---|---|---|---|---|---|
| Carpenters (47-2031) | 80% | $30.64 | $36.74 | $47.93 | $29.12 | 1.26 | metro |
| Construction laborers (47-2061) | 20% | $23.67 | $28.72 | $37.03 | $22.66 | 1.27 | metro |
| Blended | 100% | 1.26 | |||||
Is Seattle cheap or dear? The local comparison
Same job, same size (300 sq ft), priced for the nearest metros. Seattle is the priciest of the group. Yakima is the cheapest at $18,900.
| Area | Range | Midpoint | vs. here |
|---|---|---|---|
| Seattle, WAthis page | $14,100 – $28,300 | $21,200 | |
| Bremerton, WA40 miles | $12,900 – $25,900 | $19,400 | −8% |
| Olympia, WA60 miles | $12,700 – $25,500 | $19,100 | −10% |
| Yakima, WA90 miles | $12,600 – $25,200 | $18,900 | −11% |
| Bellingham, WA95 miles | $13,800 – $27,700 | $20,800 | −2% |
| Portland, OR135 miles | $13,800 – $27,600 | $20,700 | −3% |
| Washington (statewide) | $13,900 – $27,800 | $20,800 | −2% |
| United States | $12,100 – $24,200 | $18,100 | −15% |
Out of the 300 metros we cover, Seattle ranks #14 for the cost of this job (#1 is the most expensive). Statewide, Seattle is 2% above the Washington figure.
Elsewhere in Washington
| Metro | Size | Range | Midpoint | vs. here |
|---|---|---|---|---|
| Spokane, WA | 255,820 jobs | $12,500 – $25,100 | $18,800 | −11% |
| Olympia, WA | 130,300 jobs | $12,700 – $25,500 | $19,100 | −10% |
| Kennewick, WA | 129,490 jobs | $12,900 – $25,800 | $19,300 | −9% |
| Yakima, WA | 97,010 jobs | $12,600 – $25,200 | $18,900 | −11% |
| Bremerton, WA | 93,740 jobs | $12,900 – $25,900 | $19,400 | −8% |
| Bellingham, WA | 91,390 jobs | $13,800 – $27,700 | $20,800 | −2% |
Metros of a similar size
Big cities and small ones price differently, so here is Seattle against the 4 metros with the closest total employment.
| Metro | Size | Range | Midpoint | vs. here |
|---|---|---|---|---|
| San Francisco, CA | 2,373,920 jobs | $16,000 – $32,000 | $24,000 | +13% |
| Minneapolis, MN | 1,951,650 jobs | $13,900 – $27,900 | $20,900 | −1% |
| Phoenix, AZ | 2,375,760 jobs | $11,800 – $23,600 | $17,700 | −17% |
| Detroit, MI | 1,904,530 jobs | $12,800 – $25,700 | $19,200 | −9% |
Seattle weather and the composite deck calendar
Climate numbers on this page come from NOAA's 1991-2020 U.S. Climate Normals at the nearest suitable station, Seattle Sand Pt Wsfo (5 miles from the city center). They are 30-year averages, so any one year can run hotter, colder or wetter.
Weather is not a serious constraint for exterior installation in Seattle: no month in the averages is cold enough (an average daytime high under 45°F) or hot enough (an average daytime high of 90°F or more) to rule it out, so the workable window is all year.
Seattle gets about 38 inches of precipitation in a normal year, including roughly 4 inches of snow. The wettest months are January, November and December (5.8 inches in November). The station averages about 2 days a year at 90°F or above.
We do not adjust the estimate by month, because we have no reliable published data on seasonal pricing. It is still worth asking contractors whether an off-peak start date changes their bid.
| Month | Avg high °F | Avg low °F | Precip (in) | For this job |
|---|---|---|---|---|
| Jan | 47 | 37 | 5.1 | Workable |
| Feb | 50 | 37 | 3.5 | Workable |
| Mar | 54 | 39 | 3.9 | Workable |
| Apr | 59 | 43 | 3.0 | Workable |
| May | 65 | 48 | 2.2 | Workable |
| Jun | 70 | 53 | 1.6 | Workable |
| Jul | 77 | 57 | 0.8 | Workable |
| Aug | 77 | 57 | 1.0 | Workable |
| Sep | 71 | 53 | 1.7 | Workable |
| Oct | 61 | 47 | 3.6 | Workable |
| Nov | 52 | 41 | 5.8 | Workable |
| Dec | 47 | 37 | 5.5 | Workable |
Add-ons priced for Seattle
Add-ons start from national price ranges and are scaled by 1.15 for Seattle, which is the average of the area's wage index (1.26) and goods price index (1.04). The estimator above can add them to your total.
| Add-on | Local range |
|---|---|
| Add a deck railing (approx. 0.3 ft per sq ft) | $2,050 – $6,200 |
Pick a size, pick a tier: composite deck pricing in Seattle
The cited range is split into basic, standard and premium bands, then scaled to Seattle. Bands overlap, because plenty of standard jobs cost as much as a light premium one. Sizes run from 10x12 (120 sq ft) to 20x20 (400 sq ft).
Basic
$14,100 to $19,800
Entry-level composite boards, low deck, simple shape
Standard
$18,400 to $24,100
Mid-grade capped boards with railing and stairs
Premium
$22,700 to $28,300
Premium capped or PVC boards, multi-level, hidden fasteners
| Size | Basic | Standard | Premium |
|---|---|---|---|
| 10x12 (120 sq ft) | $5,700 – $8,000 | $7,400 – $9,700 | $9,150 – $11,400 |
| 12x12 (144 sq ft) | $6,800 – $9,550 | $8,900 – $11,600 | $10,900 – $13,700 |
| 16x20 (320 sq ft) | $15,100 – $21,100 | $19,600 – $25,700 | $24,200 – $30,200 |
| 20x20 (400 sq ft) | $18,800 – $26,400 | $24,500 – $32,100 | $30,200 – $37,700 |
Related projects, priced for Seattle
Jobs that often go together with composite deck are priced below at their usual sizes, using the same Seattle wage and price inputs. Compared with national midpoints, paver patio comes out highest (+23%) and wood deck lowest (+14%); the gap comes from the trades each job uses.
| Project | Size | Range | vs. US |
|---|---|---|---|
| Wood deck | 300 sq ft | $8,600 – $17,200 | +14% |
| Concrete patio | 300 sq ft | $1,450 – $4,950 | +22% |
| Paver patio | 300 sq ft | $3,700 – $6,750 | +23% |
| Gutters | 160 linear ft | $1,600 – $4,950 | +19% |
Get 3 local quotes
Tell us about the job and we will try to connect you with up to three local contractors for written quotes. It is free and you are under no obligation to hire. Your estimate of $18,400 to $24,100 for Seattle, WA is attached.
Detailed composite deck report for Seattle, WA, $9
Multi-page report for Seattle, WA: low, typical and high cost, a line-item breakdown of materials and labor by trade, permit notes, the best months to schedule, a quote comparison sheet, red flags, questions for contractors, checklists and every source. Save your estimate above, preview page 1 free, and unlock the full report for $9 one-time, or get every report with CostLocal Pro.
Composite deck in Seattle: your questions
+How much does it cost to build a composite deck in Seattle?
For 300 sq ft, expect $14,100 to $28,300 in the Seattle area. A standard-spec job lands at $18,400 to $24,100. Small jobs usually cost more per sq ft and large ones less.
+What is the price per sq ft for composite deck in Seattle?
About $47 to $94 per sq ft for materials and labor, plus $55 to $170 for the permit if one is needed. The US range is $40 to $80.
+Is composite deck cheaper in Seattle or Bremerton?
Bremerton is 40 miles away. The midpoint for 300 sq ft there is $19,400, which is 8% less than Seattle ($21,200). Wage and materials indexes both feed that gap.
+How much of the bill is labor in Seattle?
About 64% at the midpoint, or $13,600 out of $21,200. Materials are 35% and permits 1%. Nationally, labor is 60%.
+What would 16x20 (320 sq ft) cost in Seattle?
$15,100 to $30,200. Pick a different size in the estimator above to get your own number.
+Does composite deck need a permit in Seattle?
Often, but rules are set by your city or county building office, so call before you hire. Budget $55 to $170 for fees in the Seattle area (our national range of $50 to $150 scaled by the local price level).
+Is Seattle expensive for composite deck compared with the rest of Washington?
Seattle is 2% above the Washington statewide estimate ($20,800 at the midpoint). We cover 7 metros in Washington; see the state page to compare them.
+What do carpenters earn in Seattle?
The BLS median is $36.74 an hour in the Seattle area, compared with $29.12 nationally. The 25th to 75th percentile range is $30.64 to $47.93.
+What do basic and premium composite deck work cost in Seattle?
For 300 sq ft, basic work runs $14,100 to $19,800 and premium work $22,700 to $28,300. Basic means: entry-level composite boards, low deck, simple shape. Premium means: premium capped or PVC boards, multi-level, hidden fasteners.
+Is there a bad season to build a composite deck in Seattle?
Not from a temperature point of view. NOAA's 1991-2020 normals show no month with a freezing-level overnight low or a 90°F-plus average high, so timing is mostly about contractor availability and rain.
+What does "add a deck railing" add in Seattle?
$2,050 to $6,200 for 300 sq ft, from a national range scaled by the local wage and goods indexes.
Composite deck near Seattle
Where these numbers come from
Base prices are national ranges from the sources below. We scale labor by local BLS wages, materials by BEA goods prices and permits by the BEA all-items price level. Full method on the methodology page.
- HomeGuide: How Much Does Composite Decking Cost? (2026) (accessed November 4, 2026)
- HomeGuide: 2026 Building Permit Costs | Fees & Cost Calculator (accessed November 4, 2026)
- BLS Occupational Employment and Wage Statistics, May 2025
- BEA Regional Price Parities, 2024
- NOAA NCEI U.S. Climate Normals, 1991-2020