How Much Does a Deck Cost in Northern California?
What decks actually cost per square foot in wine country in 2026 — by material, by height, and including the ledger, footing, and fire-code details that separate a deck that lasts 30 years from one that fails in eight.
Last updated August 13, 2026. Figures reflect real project pricing across Sonoma, Napa, Marin and Solano counties and are reviewed each season.
Key Takeaways
- Installed deck costs run $45–$110 per square foot in Northern California — roughly $14,000–$35,000 for a typical 320 sq ft deck.
- Composite decking costs 40–70% more upfront than redwood but eliminates annual refinishing, usually breaking even around year eight.
- Height is the biggest hidden multiplier. A deck more than 30 inches above grade requires guardrails, deeper footings, and often engineering — adding 25–50%.
- Decks over 200 sq ft or more than 30 inches high require a permit in virtually every Northern California jurisdiction.
- In WUI fire zones, decking within 10 feet of the house must be ignition-resistant or noncombustible, which rules out standard wood in many wine country locations.
What This Guide Covers
What does a deck cost per square foot?
| Decking material | Cost per sq ft installed | 320 sq ft deck | Maintenance |
|---|---|---|---|
| Pressure-treated pine | $45–$60 | $14,400–$19,200 | Seal every 1–2 yrs |
| Construction redwood | $55–$78 | $17,600–$25,000 | Seal every 1–2 yrs |
| Clear heart redwood | $75–$105 | $24,000–$33,600 | Seal annually for color |
| Composite (Trex, TimberTech) | $65–$95 | $20,800–$30,400 | Wash only |
| PVC / capped polymer | $80–$110 | $25,600–$35,200 | Wash only |
| Tropical hardwood (ipe) | $90–$130 | $28,800–$41,600 | Oil annually |
These are installed costs including framing, footings, fasteners, and standard railings on a deck at moderate height. They assume reasonable access and no unusual structural conditions.
The framing matters more than the decking. Homeowners shop surface boards because that is what they see, but the substructure determines how long the deck lasts. Pressure-treated framing, properly flashed ledger connections, joist tape on every joist top, and hot-dipped galvanized or stainless hardware are what separate a 30-year deck from a callback.
Is composite decking worth it over redwood?
Composite costs roughly 40–70% more upfront. Over a 25-year horizon, it is usually the cheaper choice.
| 25-year cost | Redwood | Composite |
|---|---|---|
| Initial install (320 sq ft) | $21,000 | $26,000 |
| Refinishing (12 cycles @ $1,400) | $16,800 | $0 |
| Board replacement | $3,500 | $0 |
| Washing | $0 | $1,500 |
| 25-year total | $41,300 | $27,500 |
When redwood still wins
- You genuinely want the look and smell of real wood, and you enjoy maintaining it
- Heavily shaded decks, where composite's heat retention is a non-issue and wood dries well
- Historic or period homes in Napa, Sonoma, or Petaluma where composite reads wrong against original architecture
- Tight budgets where the upfront delta is the deciding constraint
When composite is the clear answer
- Full-sun exposures — a redwood deck in unshaded wine country sun greys and checks fast
- Pool surrounds, where chemicals and constant wet accelerate wood degradation
- Anyone who does not want a recurring weekend project every other spring
- WUI zones, where many composite products carry the required flame-spread ratings
How does deck height change the cost?
This is the factor most homeowners underestimate. Cost does not scale with area alone — it scales with elevation.
| Deck height | Cost multiplier | What changes |
|---|---|---|
| Ground level (under 30") | Baseline | No guardrail required, shallow footings, simple framing |
| 30"–6 ft | 1.25–1.5× | Guardrails required, deeper footings, taller posts with bracing |
| 6–12 ft | 1.5–2.2× | Engineered lateral bracing, larger footings, often structural stamp |
| Over 12 ft / hillside | 2–3.5× | Full engineering, drilled piers, moment connections, difficult access |
Hillside decks are common across Sonoma, Napa, and Marin, and they are structurally serious work. A deck cantilevered over a slope is carrying live load, wind uplift, and seismic lateral load simultaneously, and it is connected to your house at the ledger — historically the single most common point of catastrophic deck failure.
SB 721 and SB 326
If you own a multifamily building with three or more units, California law requires periodic inspection of exterior elevated elements — decks, balconies, stairs, and walkways — by a licensed professional. SB 721 covers apartments, SB 326 covers condominium associations. These inspections have uncovered widespread dry rot in North Bay buildings, and remediation is not optional once documented.
Do you need a permit, and what do fire codes require?
In almost every Northern California jurisdiction, a permit is required if the deck is more than 30 inches above grade, larger than 200 square feet, or attached to the house. In practice, most decks worth building need one. Permit and plan review typically runs $600–$3,500, plus engineering if elevated.
WUI decking requirements
If your property is in a Wildland-Urban Interface zone — which covers a great deal of Sonoma, Napa, and Marin County — California Building Code Chapter 7A applies to decks within 10 feet of the structure. Acceptable options include:
- Noncombustible decking such as concrete, steel framing, or aluminum systems
- Exterior fire-retardant-treated wood
- Composite or plastic decking that has passed the required flame-spread and ignition testing
- Heavy-timber dimensioned decking meeting the code's minimum section requirements
Equally important is what goes underneath. The area beneath an elevated deck must be kept clear of combustible storage and vegetation, and enclosing it with ignition-resistant material is generally the safer detail in a fire zone.
Ledger flashing is where decks fail. The connection between deck and house has to shed water and carry load. Improper flashing rots the rim joist behind the siding invisibly for years, and the failure mode is sudden. Any bid that does not specify ledger flashing detail and hardware is a bid to walk away from.
What do railings, stairs, and features add?
| Feature | Typical added cost |
|---|---|
| Wood railing (per linear ft) | $65–$110 |
| Composite railing (per linear ft) | $95–$160 |
| Cable railing (per linear ft) | $150–$280 |
| Glass panel railing (per linear ft) | $220–$420 |
| Stairs (per step, incl. railing) | $350–$700 |
| Built-in bench seating | $1,400–$4,000 |
| Low-voltage deck lighting | $1,800–$5,500 |
| Pergola over deck | $7,000–$26,000 |
| Under-deck drainage system | $16–$32 per sq ft |
Cable and glass railings are popular on view properties for the obvious reason — on a deck overlooking vineyards, a solid wood railing is the thing standing between you and the reason you built the deck. They cost two to four times more per foot, which on a 40-foot run is a real decision, not a detail.
Frequently Asked Questions
How much does a 20x20 deck cost in Northern California?
A 400 square foot deck costs approximately $18,000 to $44,000 installed in Northern California in 2026, depending on material and height. Pressure-treated at ground level sits near the bottom of that range; an elevated composite deck with cable railing sits near the top. Most homeowners in Sonoma and Napa County land between $26,000 and $34,000.
Is Trex cheaper than wood decking?
Trex and other composite decking cost more upfront than redwood or pressure-treated wood, typically 40 to 70 percent more installed. Over a 25-year period composite is usually cheaper overall because it eliminates the roughly $1,400 refinishing cycle every two years. The break-even point generally falls around year eight.
Do I need a permit to build a deck in California?
You need a building permit in most California jurisdictions if the deck is more than 30 inches above grade, exceeds 200 square feet, or attaches to the house. Freestanding ground-level decks under those thresholds are often exempt, but requirements vary by city and county, and attached decks essentially always require one.
How long does a redwood deck last in Northern California?
A properly built and maintained redwood deck lasts 20 to 30 years in Northern California, though the surface boards may need replacement around year 15 to 20 in full-sun exposures. Longevity depends far more on the substructure and ledger flashing than on the decking material, and neglecting the refinishing cycle can cut lifespan by half.
Can I build a wood deck in a fire zone?
In a Wildland-Urban Interface zone, decking within 10 feet of the structure must be noncombustible, fire-retardant-treated, or a composite product that has passed required flame-spread testing under California Building Code Chapter 7A. Standard untreated redwood or pine decking generally does not comply in that zone, though it may be permitted farther from the building.
Related Guides
Ready to build the deck?
Phil will look at your grade, your exposure, and your view, then tell you honestly what material makes sense and what it will cost. Written line-item estimate, no charge.
Get Your Free Estimate →