In Washington, a standard 300 sqft deck runs roughly $21,227–$30,477 depending on material. Labor runs 18% above the national average, and permits typically cost about $360. Frost-line footings add 8–12% to the build.
Cost by material — 300 sqft deck in Washington
Standard 12×25 deck, 3–5 ft off ground, composite balusters, one stair run. Includes framing, footings, railing, stairs, permit, and 8% contingency.
Pressure-Treated Pine
15–20 yrs · Stain every 2–3 yrs
$71/sqft
$21,227
Cedar / Redwood
20–25 yrs · Seal every 2–3 yrs
$79/sqft
$23,597
Composite (Trex, TimberTech)
25–30 yrs · Rinse yearly
$92/sqft
$27,504
PVC / Cellular
30+ yrs · Rinse yearly
$102/sqft
$30,477
Ipe / Cumaru Hardwood
40+ yrs · Oil annually (optional)
$108/sqft
$32,542
What drives cost in Washington
Labor (118% of national avg). Contractor rates are significantly above average here — expect to pay a premium for experienced deck crews.
Permits (~$360). Most Washington municipalities require a building permit for any deck over 30 inches. Inspections typically happen at the footing and final stages.
Frost-line footings. Washington's frost line forces footings 36–48 inches deep, adding roughly $50–80 per pier and extra concrete volume. Budget 8–12% more than warm-climate equivalents.
Materials. Pressure-treated pine is the cheapest per sqft; composite (Trex, TimberTech) is 2–3× more but almost maintenance-free. Most Washington homeowners picking a mid-tier build land on composite.
Washington deck cost — FAQ
How much does a deck cost in Washington?+
In Washington, a standard 300 sqft deck runs about $21,227 for pressure-treated pine to $32,542 for ipe hardwood. Most homeowners picking mid-tier composite (Trex, TimberTech) land near $27,504 — roughly $92 per square foot installed.
Do I need a permit for a deck in Washington?+
Most Washington municipalities require a building permit for any deck over 30 inches off the ground or attached to a house. Permit fees typically run around $360. Inspections usually happen at the footing stage and at final.
What's the cheapest deck material in Washington?+
Pressure-treated pine at about $71 per square foot installed. Cedar is the next step up at $79/sqft. For long-term cost-of-ownership (accounting for stain and maintenance), composite at $92/sqft often wins past year 12.
How much is labor for a deck in Washington?+
Washington labor runs 118% of the US average — 18% above the national baseline. Labor accounts for 40–55% of total deck cost. On a 300 sqft composite build, that's roughly $13,202 of the total.
Do I need frost-line footings in Washington?+
Frost-line footings push 36–48 inches deep in this state, adding roughly 8–12% to total cost vs warm-climate equivalents. Most Washington jurisdictions require footings below the local frost line, verified at inspection.
Does a deck add home value in Washington?+
Yes. Nationally, a new deck returns 50–70% of its cost at resale. In Washington's climate, an outdoor living space is especially valued despite the shorter usable season. Real estate appraisers typically credit deck value at 50–65% of installed cost; buyers tend to value it even higher when a property is actively listed.
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