Worked example: a 320 sq ft composite deck, 3 ft off grade
At $40/sq ft with a 1.12 height factor, the deck itself is $14,336. Sixty feet of composite-matched railing adds $3,300, one stair set $760 — total near $18,400, or $57/sq ft all-in. The identical deck in pressure-treated runs ~$9,500, but you'll spend $1,500–$2,000 per decade maintaining it and replace boards around year 15, while the composite carries a 25-year warranty.
- • Framing is always pressure-treated regardless of surface — composite only replaces the top 2 inches of the structure.
- • Hidden-fastener systems add ~$1/sq ft and are the difference between a clean surface and 1,000 visible screw heads.
- • Permits are required nearly everywhere for attached decks; footings must pass inspection before framing.
Deck vs patio at the same footprint
A ground-level paver patio runs $15–$30/sq ft — cheaper than any elevated deck and maintenance-free. Decks win when the yard slopes, when the door is more than ~2 ft off grade, or when you want the under-deck drainage/storage. If your door is at grade, price a patio before committing to a deck.
FAQ
How much does it cost to build a deck in 2026?
The national average is around $8,000. Pressure-treated runs $15–$25 per sq ft installed, composite $30–$50 — so a 300 sq ft deck lands at $6,000–$15,000 depending on material and height.
Is composite decking worth the extra cost?
Usually yes above 250 sq ft: it eliminates $1.50–$2/sq ft of staining every 2–3 years and carries 25–50 year warranties. The 10-year total cost of ownership often beats wood.
How long does it take to build a deck?
A pro crew builds a standard 300 sq ft deck in 1–2 weeks including footing inspection. Permit approval adds 2–6 weeks before work starts.
Does a deck add home value?
Wood decks recoup ~65% of cost at resale, composite ~60% — but outdoor living space consistently ranks among the most-wanted buyer features, so the saleability boost usually exceeds the raw recoup number.
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