Composite decking costs 2–3x more upfront than pressure-treated wood — but in freeze-thaw and coastal climates, 20-year total cost of ownership often favors composite decisively.
The upfront cost difference between composite and pressure-treated wood decking is significant — but it's only part of the story. A 400 sq ft composite deck costs $14,000–$24,000 installed vs. $6,000–$10,000 for pressure-treated wood. However, wood requires annual sealing ($300–$600/year), periodic staining ($800–$1,500 every 3–4 years), and board replacement as sections fail.
| Metric | Pressure-Treated Wood | Composite (Trex/TimberTech) |
|---|---|---|
| Initial install (400 sq ft) | $6,000–$10,000 | $14,000–$24,000 |
| Annual sealing | $300–$600/yr | $0 |
| Staining (every 3–4 yrs) | $800–$1,500 | $0 |
| Board replacement (20 yr) | $1,500–$4,000 | $500–$1,500 |
| 20-year total cost | $16,000–$26,000 | $15,000–$26,000 |
| Lifespan | 15–20 years | 25–30 years |
Over 20 years, composite and wood end up at roughly similar total costs in moderate climates — but climate changes this calculation dramatically.
Freeze-Thaw Climates (Northeast, Midwest): Wood decking in freeze-thaw climates faces accelerated degradation. The repeated expansion and contraction cycles cause boards to cup, warp, and crack more quickly. In Minneapolis or Boston, a pressure-treated wood deck may need full board replacement in 12–15 years rather than 20. Composite is virtually unaffected by freeze-thaw cycles, making it the clear 20-year value choice in Northern markets.
Coastal Markets (Florida, Gulf Coast, Pacific Coast): Salt air and UV exposure accelerate corrosion on hardware and UV fading on wood. Composite with UV inhibitors holds its color significantly better, and stainless or coated hardware eliminates rust issues. Coastal wood decks often need partial replacement in 10–12 years.
Arid Climates (Phoenix, Las Vegas): Extreme heat causes significant thermal expansion in composite decking — hidden fastener systems are essential. Wood bleaches and cracks quickly in intense UV. Composite with proper fastening handles desert climates well; wood requires more aggressive sealing and replacement cycles.
Pacific Northwest (Seattle, Portland): Constant moisture accelerates rot in untreated wood surfaces. Composite is strongly favored by contractors and homeowners in high-rainfall climates for this reason.