Deck Building Cost in Kennewick, WA (2026)
Updated October 2026 · Kennewick, WA · index 1.13
How much does it cost to build a deck in Kennewick? For a 300 sq ft deck with pressure-treated wood, homeowners in Kennewick, WA pay about $12,700 on average, and most quotes land between $8,800 and $16,600 — $29 to $55 per sq ft. The price covers plans and the permit, footings, a framed and flashed structure, the deck boards, railing, one set of stairs, fascia and cleanup.
The deck building price in Kennewick runs 13% above the U.S. average: construction labor in the Kennewick area runs 22% above the national mean, materials sit at the national level. The same job averages $11,300 nationally and about $13,100 at the Washington statewide index.
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Deck building price in Kennewick by decking material
What a 300 sq ft deck costs in Kennewick with each decking material, installed:
| Option | Average · range |
|---|---|
| Pressure-treated woodtreated pine or fir boards, stained and sealed$42 per sq ft | $12,700$8,800 – $16,600 |
| Capped compositehidden fasteners and a picture-frame border$51 per sq ft | $15,300$10,800 – $19,700 |
The least expensive option in Kennewick is pressure-treated wood, at about $12,700; capped composite averages $15,300, 1.2 times as much.
Cost to build a deck in Kennewick by size
With pressure-treated wood, priced for Kennewick, WA:
| Size | Average · range |
|---|---|
| A 200 sq ft deck$46 per sq ft | $9,150$6,250 – $12,000 |
| A 300 sq ft deck$42 per sq ft | $12,700$8,800 – $16,600 |
| A 400 sq ft deck$41 per sq ft | $16,300$11,300 – $21,200 |
Some costs stay the same whatever the size — plans, permit and layout, one set of stairs (4 steps), final inspection and cleanup — so a bigger job costs less per unit: $41 per sq ft for a 400 sq ft deck against $46 for a 200 sq ft deck.
What a deck building in Kennewick includes
Line by line, the $12,700 average for a 300 sq ft deck breaks down like this: 47% labor, 53% materials and equipment.
| Line | Low – high |
|---|---|
| Plans, permit and layout | $420 – $1,250 |
| Ground prep, fabric and gravel | $250 – $620 |
| Footings below the frost line | $470 – $940 |
| Flashed ledger on the house | $280 – $550 |
| 6x6 posts | $310 – $620 |
| Beams | $280 – $550 |
| Joist framing with hangers | $1,600 – $2,750 |
| Deck boards | $1,500 – $2,250 |
| One set of stairs (4 steps) | $580 – $1,150 |
| Railing | $2,150 – $3,700 |
| Fascia and skirting | $410 – $970 |
| Final inspection and cleanup | $170 – $420 |
| Stain and seal, two coats | $370 – $870 |
Each line is the price book's U.S. rate for that step, scaled by 0.74 to the installed price published sources give for the whole job (see how these prices are built), times Kennewick's index of 1.13; permit fees are not scaled.
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What affects deck building prices in Kennewick
Labor and materials in Kennewick
Construction wages in the Kennewick area run 22% above the U.S. mean (BLS, May 2025), and materials in its ZIP codes price right at the national average. Together they give Kennewick a construction cost index of 1.13.
Where Kennewick sits in Washington
Kennewick is the 23rd most expensive of the 32 Washington cities in our index, against a statewide index of 1.16. Seattle is the dearest at 1.25; Yakima is the least expensive at 1.04.
Against the rest of the country
Of the 306 U.S. cities in JobFlex's index, Kennewick ranks 65th from the most expensive. The job that averages $12,700 here averages $11,300 at the national rate.
Frost depth in Washington
Deck footings go below the frost line, or they heave by the second spring. The typical code frost depth in Washington is about 18 in.. Your building department sets the exact figure.
The deck code in Washington
Decks here are built to the 2021 Washington State Residential Code, WAC 51-51 (2021 IRC with Washington amendments). Guards are required at 36 in. where the deck is more than 30 in. up, and stair risers can be up to 7.75 in. Washington does not adopt the IRC's deck beam tables R507.5(1)–(4): deck beams are sized from Washington's own Table R507.5 (60 psf live or 70 psf ground snow, WAC 51-51-0507) — confirm the beam sizes here against it.
What decks are built of in Washington
Most used on decks in Oregon and Washington: capped composite, then cedar, then treated hem-fir or fir 2x6.
Sales tax in Washington
Washington's base state sales tax is 6.5%, and cities and counties can add their own. How it applies to a home-improvement contract varies, so ask whether a quote includes it. Prices on this page are before tax.
What a Kennewick contractor will ask before quoting
- Reuse the frame or rebuild?
- Height, railing style and stairs
- Board brand and color
Deck building cost in other Washington cities
A 300 sq ft deck with pressure-treated wood averages $12,700 in Kennewick; $12,700 in Tri-Cities, $12,700 in Richland, $11,700 in Yakima.
| City | Average · range |
|---|---|
| Tri-Cities, WAsame as Kennewick | $12,700$8,800 – $16,600 |
| Richland, WAsame as Kennewick | $12,700$8,800 – $16,600 |
| Yakima, WA8% less | $11,700$8,100 – $15,300 |
| Pasco, WA1% less | $12,600$8,700 – $16,500 |
| Bellingham, WA3% more | $13,100$9,050 – $17,100 |
| Wenatchee, WA1% less | $12,600$8,700 – $16,500 |
| Vancouver, WA2% less | $12,500$8,650 – $16,300 |
| Spokane, WA6% less | $11,900$8,250 – $15,600 |
deck building price in Kennewick: questions
How much does it cost to build a deck in Kennewick, WA?
About $12,700 for a 300 sq ft deck with pressure-treated wood, and most Kennewick quotes fall between $8,800 and $16,600. That is 13% above the U.S. average, where the same job averages $11,300.
What is the deck price per square foot in Kennewick?
$29 to $55 per sq ft, about $42 on average with pressure-treated wood. Smaller jobs cost more per unit, because the fixed costs are spread over less.
How much is a 400 sq ft deck in Kennewick?
$11,300 to $21,200, about $16,300 on average, with pressure-treated wood — $41 per sq ft.
Do you need a permit for deck building in Kennewick?
Yes — a new deck needs a permit nearly everywhere, Kennewick included. In Washington, decks follow the 2021 Washington State Residential Code, WAC 51-51 (2021 IRC with Washington amendments). The prices on this page carry $420–$1,250 for plans, permit and layout.
Does the price include sales tax in Washington?
No. The prices here are before tax; Washington's base state rate is 6.5%, plus any local rate.
What decking do people choose in Washington?
Most used on decks in Oregon and Washington: capped composite, then cedar, then treated hem-fir or fir 2x6.
Other home projects in Kennewick
Deck building cost in Washington
How these prices are built
Every price on this page comes from JobFlex's contractor price book: what a homeowner pays a licensed contractor for each step of the job, as a U.S. national average per unit, with the contractor's overhead and profit included and sales tax left out. The deck building is priced step by step, then multiplied by Kennewick's construction cost index of 1.13.
Where the price book's steps for an option add up to more than 20% over the installed price a published source gives for the whole job, every step but a permit fee is scaled down to the middle of that range: pressure-treated wood × 0.74 (HomeGuide 2026: $25–$50 per sq ft); capped composite × 0.80 (Ergeon 2026: $30–$60 per sq ft).
The index weighs local construction wages (BLS Occupational Employment and Wage Statistics, May 2025) at 60% and the area's material prices (Craftsman ZIP-area factors) at 40%. Published indices for Kennewick, each on its own base: Craftsman 1.01. Treat any city figure as about ±5%; a contractor's quote for your house is the number to plan with.
Contractors in Kennewick build quotes like these with JobFlex's Deck Studio.
- HomeGuide 2026: pressure-treated deck $25-$50/sqft installed, labor $15-$30/sqft
- Ergeon 2026: composite deck $30-$60/sqft installed
- HomeGuide 2026: composite railing $25-$60/lf, aluminum $50-$200/lf installed