How much does it cost to build a deck?

A 320 square foot pressure-treated deck costs $8,000 to $16,000 installed. Composite runs $12,800 to $25,600 for the same size. Here is where every dollar goes.

Tallyard EditorialUpdated April 20, 2026Reviewed against HomeGuide, Angi, and NADRA contractor cost surveys

The real number, not the range

Most deck cost articles give you a range so wide it is useless: "$15 to $80 per square foot." That 5× spread exists because they lump a ground-level platform made of pressure-treated pine with a second-story composite deck that has cable railing and a spiral staircase. Those are not the same project. Here is how to find your actual number.

Start with the three things that determine 90 percent of the final price: deck size (square footage), material choice (pressure-treated, cedar, composite, or hardwood), and height above ground (ground-level needs short posts and no stairs; elevated needs tall posts, a full staircase, and sometimes an engineer-stamped plan). Everything else is a line-item detail.

Fig. 1. Pressure-treated is the budget baseline. Composite roughly doubles the surface cost but the frame underneath (always pressure-treated lumber regardless of surface material) stays the same price.

How we calculated these numbers▾

Cost data aggregated from HomeGuide 2025-2026 contractor surveys, Angi project cost database, and NADRA (North American Deck and Railing Association) member pricing reports. Regional multipliers from RS Means residential cost data. All prices are fully installed including materials, labor, permits, and standard railing. Prices do not include demolition of existing structures.

Where the money actually goes

Fig. 2. The decking surface you walk on is about 30% of the total cost. The other 70% goes to the invisible structure, hardware, and labor. This is why composite decks are not 2× the price of wood decks — only the surface layer changes; the frame is the same.

The frame lumber (joists, beams, ledger board) is always pressure-treated regardless of your decking surface material. A composite deck has the same frame as a wood deck. The surface boards, fasteners, and railing change. The frame does not. This is why composite costs 1.6 to 2 times more than wood overall, not 2 to 3 times more: only the surface layer is more expensive.

Cost by deck size

Fig. 3. Cost scales roughly linearly with area. A 320 ft² deck is not quite double the cost of a 192 ft² deck because mobilization, permits, and minimum stair costs are fixed.

The most popular residential deck size is 12 × 16 or 16 × 20. Smaller than 10 × 10 and the per-square-foot cost rises because fixed costs (permit, mobilization, minimum stair) are spread over less area. Larger than 20 × 24 and the per-square-foot cost drops slightly because framing becomes more efficient with longer spans. Use the deck calculator to get an exact material list for your dimensions.

DIY vs professional: where the savings actually are

	DIY	Professional
Decking surface (320 ft²)	$1,400–3,000	$1,400–3,000
Frame lumber	$800–1,200	Included
Posts + concrete footings	$300–500	Included
Fasteners + joist hangers	$200–350	Included
Stairs + railing	$400–900	Included
Permit	$100–500	$100–500
Labor	$0 (3–5 weekends)	$3,000–8,000
Total (16×20 PT)	$3,200–6,450	$8,000–16,000

DIY saves 50-60% but requires framing knowledge. The ledger board connection (where the deck attaches to the house) is the most safety-critical joint and the one most DIYers get wrong.

The ledger board is not optional

The ledger board connection is responsible for more deck collapses than any other single failure point. It must be lag-bolted (not nailed) into the rim joist of the house, with self-adhesive flashing behind it to prevent water infiltration. If you DIY everything else, consider hiring a contractor to install just the ledger. It takes 2 hours of professional time and prevents the catastrophic failure mode.

Regional pricing: the same deck costs 40% more in Seattle than in Atlanta

Fig. 4. Labor rates are the primary driver of regional variation. Material costs vary less than 10% across regions, but labor varies 40% or more.

Example project · Denver, CO

A homeowner got three bids for a 14 × 20 composite deck, 4 feet above grade with stairs and cable railing. Bid A: $18,500. Bid B: $22,000. Bid C: $16,200. The spread was $5,800 between highest and lowest. Bid C was from a one-man crew who subcontracted the railing. Bid B included architect-stamped plans (required in this jurisdiction for decks over 30 inches). Bid A was the sweet spot: licensed, insured, pulled the permit, and included a 2-year warranty on workmanship. Always get at least three bids and compare what is included, not just the bottom line.

Based on typical project dimensions and 2026 material pricing.

The costs most estimates leave out

Fig. 5. Permits, staining, demolition, grading, and electrical are real costs that appear on the final invoice but rarely in online cost estimates.

If you are replacing an existing deck, demolition and disposal adds $500 to $1,500 depending on size and how the old deck was built. Decks screwed together come apart in a day. Decks nailed together with ring-shank nails take twice as long because every board fights you. If your yard slopes toward the house, grading the area under and around the deck to direct water away adds $300 to $1,000 but prevents the foundation moisture problems that eventually cost far more.

Financing and return on investment

A deck addition recoups 60 to 75 percent of its cost at resale according to Remodeling Magazine's Cost vs Value report. A $12,000 deck adds roughly $7,200 to $9,000 in home value. That makes it one of the better-returning exterior projects (behind only garage doors and manufactured stone veneer). It does not fully pay for itself, but it comes closer than a kitchen or bathroom remodel typically does.

For exact material quantities, use the deck calculator. For a complete material list with quote comparison, the deck project planner chains decking, frame, footings, and stairs into one tool. For material selection help, read the composite vs pressure-treated vs cedar buying guide.