A pressure-treated wood deck costs $18–$42 per square foot installed, about $7,800 for a 12×20 with a stair set. Composite runs $25–$55/sq ft ($11,400 for 300 sq ft). Composite costs more up front but usually wins over 20 years once sealing is counted.

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Deck Cost per Square Foot by Material (Ground-Level, Installed)

MaterialLow / sq ftTypical / sq ftHigh / sq ft300 sq ft Deck
Pressure-treated pine$18$30$42$5,400 – $12,600
Cedar or redwood$25$40$55$7,500 – $16,500
Composite$25$38$55$7,500 – $16,500
PVC / polymer$32$48$65$9,600 – $19,500
Hardwood (ipe)$40$55$75$12,000 – $22,500

National 2025-26 installed ranges including framing, footings, standard railing, and labor for a ground-level deck. Raised decks add about 10% and second-story decks about 55% (deeper footings, taller structure, full perimeter guardrail).

Composite vs Wood: 20-Year Cost of Ownership

Pressure-Treated WoodComposite
Upfront, 300 sq ft installed~$9,000~$11,400
Yearly upkeep$250 – $600 (clean & seal every 2–3 yrs)$50 – $150 (soap & rinse)
Typical lifespan15 – 20 years25 – 30 years
Est. 20-year total~$17,500~$13,400
Resale recoup~75% – 85%~50% – 65%
Fade & splinterWeathers gray without sealingHolds color, no splinters

20-year totals use typical mid-range installs plus midpoint upkeep ($425/yr wood, $100/yr composite); recoup figures follow Remodeling magazine's Cost vs. Value Report trends. Composite's edge grows if you'd otherwise pay someone to seal the wood.

How the Deck Cost Calculator Works

Deck pricing runs by the square foot, installed, with height and railing as the big modifiers. This calculator prices the five common decking materials at ground level and scales for height, stairs, and railing upgrades.

The formula

Total = length × width × material rate ($30/sq ft pressure-treated, $38 composite, and so on, each with low and high bounds) × height factor (1.00 ground, 1.10 raised, 1.55 second story) + stairs ($400–$900 per set wood, $600–$1,300 composite or PVC) + railing upgrade per linear foot of guarded edge. Railing length assumes an attached deck railed on three sides: length + 2 × width.

How to use it

Enter the deck's finished dimensions. Pick ground level for walk-out platforms under 2 ft, raised for the common 3 to 6 ft backyard deck, and second story for balcony-height builds. Standard builder's rail is already in the base price; only add a railing upgrade if you want cable, glass, or metal balusters, which are priced per foot of edge.

A worked example

A 12×20 (240 sq ft) ground-level pressure-treated deck with one stair set and standard railing: $18–$42 per sq ft plus $400–$900 for stairs, or $4,720 to $10,980, with about $7,800 typical. That's the median American backyard deck.

Now the premium version: a 20×15 (300 sq ft) second-story composite deck with a stair set and cable railing. 300 × $25–$55 × 1.55 = $11,625 to $25,575, plus $600–$1,300 for composite stairs and cable rail at $55/LF across the 50 ft guarded edge ($2,750 typical). Total: about $21,320 typical, ranging $14,975 to $29,625. Height and railing did most of that, not the square footage.

Numbers are national planning ranges; lumber and composite pricing move with the commodity market, so collect three bids.

Frequently Asked Questions

How much does a 12x12 deck cost?

A 12x12 (144 sq ft) pressure-treated wood deck at ground level runs about $2,600 to $6,000 installed, with $4,300 typical. The same footprint in composite runs $3,600 to $7,900. Raised or second-story builds, extra stairs, and upgraded railings add from there.

Is a composite deck cheaper than wood?

Up front, no: composite runs $25–$55 per sq ft installed versus $18–$42 for pressure-treated pine. Over 20 years, usually yes. On a 300 sq ft deck, wood costs about $9,000 up front plus $250–$600 a year in cleaning and sealing, while composite costs about $11,400 up front plus $50–$150 a year to maintain. That's roughly $17,500 for wood versus $13,400 for composite over two decades.

How much does a second-story deck cost?

About 55% more than a ground-level deck in the same material, or roughly $45 per sq ft for pressure-treated wood (versus $30 at grade). The premium pays for deeper footings, taller posts or steel framing, a ledger attachment with proper flashing, engineering, and guardrails on all open sides.

What is the most expensive part of building a deck?

The framing and substructure: posts, footings, beams, and joists typically run a third of the total. This is also why raised and second-story decks cost so much more: the geometry of support grows while the visible decking surface stays the same.

Do decks add value to a home?

Wood decks are one of the better-value exterior projects: Remodeling's Cost vs. Value Report shows a wood deck addition recouping roughly 75% to 85% of cost. Composite decks recoup less, closer to 50% to 65%, since buyers pay for the deck, not the brand of board.

How long does a composite deck last?

Composite decking lasts 25 to 30 years with basic care, versus 15 to 20 years for pressure-treated pine that's cleaned and sealed every 2 to 3 years, 20 to 30 for cedar, and 40-plus for hardwoods like ipe. Warranties on composite often run 25 to 30 years against fading and staining.

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