Deck Build Cost Calculator

At national-average pricing, a ground-level 280 sq ft deck with 42 ft of railing, 5 steps, and a permit runs about $10,000 in pressure-treated pine (roughly $8,000–$13,500) and about $13,600 in composite ($10,900–$18,300). Angi's 2026 data puts typical deck builds at $4,340–$12,652 nationally; our 280 sq ft default lands near the top of that band because it includes railings, stairs, and the permit fee that bare-platform quotes leave out.

In most jurisdictions, yes — permits are required whenever the deck attaches to the house, stands more than 30 in. above grade, or carries a roof/structure. Expect to submit a simple site plan with the application: deck footprint, setbacks from the property lines, and the ledger attachment detail. Fees typically run $100–$500 (we model $250 typical). Skipping the permit can force teardown, block a future home sale, and void contractor insurance, so treat it as mandatory unless your building department says otherwise.

On a 280 sq ft deck, composite adds roughly $3,500 up front (about $13,600 vs $10,000 installed). You get it back slowly: composite boards last 25–30 years with soap-and-water cleaning, while PT decking needs staining every 2–3 years ($300–$600 a visit) and board replacement by year 15–20. If you'll stay in the home 10+ years, most owners find the math works; run our deck material compare tool for the 25-year total-cost view.

Railing runs about $50–$90 per linear foot installed (posts, rails, balusters, labor), and each stair step adds roughly $65–$110 — Angi's floor for basic wood stairs is $25–$50 per step, with finished composite or capped stairs well above that. A ground-level deck under 30 in. usually needs neither, which is why low decks cost half as much per square foot.

Plan on one footing per 4–6 ft of beam span — a 14×20 deck on two beams typically takes 8. Frost depth governs how deep each pier goes (4 ft in Chicago, none in Florida), and undisturbed soil or engineered helical piers cost more than a poured tube. Our model prices a dug-and-poured concrete footing at about $150–$250 each installed.

A simple ground-level PT deck goes up in 1–3 days once materials arrive. Raised or elevated composite decks with railings and stairs typically take 4–7 working days. The hidden calendar item is the footing cure: most departments inspect footings before the pour, and the concrete should cure — commonly several days, longer in cold weather — before it carries framing loads, so plan a pause between dig day and frame day on top of the week or two the permit itself takes.

Deck framing is structural carpentry: beams, joists, ledger flashing, and stairs all have load-path requirements inspectors check. Decks.com pegs deck labor at $8–$22 per sq ft on its own, which is why a build that looks like $10 of lumber is $25–$55 per sq ft installed. Complex heights, hidden fasteners, and hardwoods (which need predrilling) push labor up further.