Deck Build Cost Calculator
| Deck | PT pine mid | Cedar mid | Composite mid |
|---|---|---|---|
| 10×12 (120 sq ft) | $2,700 | $3,900 | $5,400 |
| 12×16 (192 sq ft) | $4,300 | $6,200 | $8,600 |
| 16×20 (320 sq ft) | $7,200 | $10,400 | $14,400 |
Decks are priced by the square foot of surface, and the material choice is most of the decision: pressure-treated pine runs $15-30 per square foot installed, cedar $25-40, composite $30-60, and capped PVC $40-70. A 12x16 foot deck (192 sq ft) lands mid-band near $4,300 in PT pine and $8,600 in composite before options.
The surface is not the whole job: railings, stairs and permits typically add 20-40 percent on code-covered builds, and raising the deck off the ground (walk-out basement style) adds roughly 30 percent more structure - beams, footings and posts do the work the ground was doing for free. Composite costs double the lumber but skips the annual stain cycle; over fifteen years the maintenance gap narrows faster than most lumber salesmen admit.
One chemical note worth knowing before you buy: the arsenic-based treatment (CCA) left the residential market at the end of 2003 - modern pressure-treated lumber uses copper-based systems, which is why today's PT is safe for the garden-adjacent deck and why very old decks are a different disposal conversation.
How to use
- Sketch the footprint and get the square foot area - most residential builds run 120 to 400 sq ft.
- Pick the material band honestly: PT pine is the value, cedar the natural look, composite the low-maintenance middle, PVC the top shelf.
- Set the height - ground-level patio decks skip most of the structure cost; raised walk-outs pay 30 percent more for beams and footings.
- Compare the mid and band to two bids, then make railing runs, stair count and permit fees explicit line items rather than allowances.
Frequently asked questions
How much does it cost to build a 12x16 deck?
At 192 square feet, a ground-level PT pine deck lands mid-band around $4,300 installed (band roughly $3,000-5,600), cedar near $6,200, and composite near $8,600. Add 20-40 percent if code requires railing runs and stairs, and 30 percent more for a raised structure.
Is a composite deck worth the extra cost?
The math is maintenance vs sticker: composite doubles the build price but skips the clean-and-stain cycle that PT decks need every 2-3 years - roughly $300-500 a cycle or a sweaty weekend. On a 20-year horizon the total costs converge; what never converges is the look at year ten, where composite stays uniform and PT shows its weathering. Buy composite if you plan to keep the house; buy pine if the deck might not outlive your plans.
How much do railings and stairs add?
Railings run $20-60 per linear foot depending on material (composite and metal rails sit at the top), and a typical 12x16 deck with code-required guard sections needs 30-50 feet of rail. Stairs add $100-300 per step with landings. Together they commonly add 20-40 percent to a bare-platform quote - the line items to make explicit.
What is the cheapest way to build a deck?
Ground-level, pressure-treated, simple rectangle, no rail requirement under local code height limits: that combination lands near $15 per square foot at the low band. The expensive surprises are access (no equipment access means hand-carry labor), sloped grades needing footings, and changing the plan mid-build - permits exist precisely because moving a beam is cheaper on paper than in lumber.
Does a deck add home value?
Wood decks historically recoup most of their cost at sale - often the best exterior return in remodeling surveys - with composite close behind and gaining. The honest framing: a deck returns value the way a maintained lawn does, by not subtracting; a rotten deck subtracts twice, in appraisal and in the buyer's imagination. Build it well, keep it sealed, and it pays its way.