Composite Decking vs. Wood Decking in Washington County
Composite decking typically runs $40 to $65 per square foot installed in Washington County, compared to $25 to $40 per square foot for pressure treated wood, but the wood needs a fresh stain or sealant every two to three years while composite mainly needs an occasional rinse. Over 20 years, wood's upkeep costs and shorter lifespan often close the price gap with composite.
What composite and wood decking cost in Washington County
Pressure treated wood decking installed in the Hillsboro area typically runs $25 to $40 per square foot, including labor, framing, and hardware. Composite decking runs higher upfront, usually $40 to $65 per square foot installed, since the boards themselves cost more than lumber even though labor time is similar.
The gap narrows over time. Wood needs a fresh coat of stain or sealant every two to three years to keep water out of the grain, plus regular cleaning to prevent mildew in our wet winters. Composite needs little beyond an occasional rinse with a hose or pressure washer on a low setting.
| Factor | Pressure-treated wood | Composite |
|---|---|---|
| Installed cost per sq ft | $25 to $40 | $40 to $65 |
| Typical lifespan | 15 to 20 years | 25 to 30+ years |
| Maintenance | Restain or seal every 2 to 3 years, regular cleaning | Occasional wash, no staining or sealing |
How the Willamette Valley climate affects each material
Washington County gets roughly 35 to 45 inches of rain a year, most of it between October and April. Wood decking left unsealed or with peeling stain absorbs that moisture, which can lead to swelling, cupping, and eventually rot at the joints and around fasteners.
Composite decking doesn't absorb water the way wood does, so it tends to hold up better through wet winters. It's also more resistant to the moss and algae growth common on shaded decks tucked under mature Douglas firs or on the north side of a house.
Other factors worth weighing before you decide
Cost and climate aren't the only considerations.
- HOA rules: many newer subdivisions in Hillsboro, Beaverton, and Aloha have HOA guidelines specifying approved deck colors or materials, so check your CC and Rs before ordering either product.
- Resale expectations: composite is often seen as a low-maintenance selling point, but some buyers still prefer the look of real wood.
- Heat underfoot: darker composite boards can get noticeably hot on sunny summer afternoons, while lighter composite or wood stays cooler barefoot.
- Repairability: a damaged wood board can be unscrewed and replaced for the cost of one board, while matching an older composite line can be harder if that color has been discontinued.
Frequently asked questions
Does composite decking fade in the Pacific Northwest sun?
Most modern cap-stock composite resists UV fading and moisture better than wood, though older or budget composite lines can fade noticeably over 10 to 15 years.
Can composite decking be installed over an existing wood frame?
Yes, most composite decking is installed over the same pressure treated joists and framing used for wood decking, only the surface boards change.
Does a wood deck need to be replaced entirely if part of it rots?
Not always. Contractors can often replace individual damaged boards, but widespread rot around ledger boards or joists usually signals a full rebuild.
Is composite worth the extra upfront cost for a newer subdivision home?
If you plan to stay 10 or more years, the lower long-term maintenance often offsets the higher initial price. For a shorter hold, the upfront savings of wood may make more sense.