1. Building season & climate in Washington
Western Washington, including the Puget Sound area, has a mild, wet climate that supports a long building season with few hard freezes; eastern Washington's more continental climate has a shorter, more clearly defined season.
2. Footing depth in Washington
Frost depth requirements are generally shallow to moderate west of the Cascades and deeper east of them — this is another state where a single statewide number would be misleading. Confirm locally.
For the general reasoning behind frost-depth footing requirements, see the footing depth by frost line guide.
3. Common material choices in Washington
Regional pattern
4. Typical cost for a 12×16 deck in Washington
A 12×16 deck is 192 sq ft. Applying the broad national installed-price ranges from our cost guide gives a starting range before Washington-specific factors:
Cedar/redwood: 192 × $35–$55 = $6,720–$10,560
Composite: 192 × $40–$65 = $7,680–$12,480
What moves a Washington quote up or down from these national ranges:
- Required footing depth (section 2): deeper footings mean more concrete, digging, and labor per post.
- Building season (section 1): contractors often price higher in the busy months and may have openings, or schedule gaps, off-season.
- Deck height: a raised deck adds stairs, longer posts, and more railing.
- DIY vs. contractor: doing it yourself removes labor, which is a large share of the installed price.
Ranges, not a quote
5. Build your Washington deck estimate
General installed-price ranges by material are in the deck cost per square foot guide, with a full worked example in the 12×16 deck cost guide. For your own dimensions, start with the deck board calculator and work through joists, footings, fasteners, and railing.
Once you have your local footing depth from the building department, enter it in the footing concrete calculator to get bags of concrete per footing. The Project Summary then puts boards, joists, fasteners, concrete, and railing on one sheet you can export for the lumber yard.