Project cost · modeled example

12x12 Deck Cost: Pressure-Treated, Itemized (2026 Baseline)

A 144-square-foot pressure-treated deck off a back slider, about 3 feet up: footings, framing, decking, railing and one stair, itemized with crew hours.

Direct answer: Building a 12x12 pressure-treated deck about 3 feet off grade has a direct job cost of $8,677 for this deck in this example. At illustrative markups of 30% to 100%, that is a selling price of about $11,280 to $17,354. Direct job cost is labor and materials only, with no contractor overhead or profit, and is not a price: no contractor performs work at job cost. Permit and inspection fees are not included.
Clamp's Generate from description screen with the 12x12 deck described in plain words

Describe it

The estimate for the 12x12 deck in Clamp's builder: total $8,677.10, grouped into carpentry

Every line, by trade

The 12x12 deck in the Clamp app: described in plain words, then the draft at $8,677 job cost, every line grouped by trade. Sample data.

The job at a glance

One build, fully itemized, with crew hours.

BuildJob costLaborCrew hoursMaterialsIllustrative selling price
A. 12x12 pressure-treated deck$8,677$3,94348 to 69 h$3,434$11,280 to
$17,354

Dump fees and other costs ($1,300) are the same in every build and included in the job cost. Materials include allowances. Illustrative selling price is the job cost at a 30% to 100% markup; your price depends on your own overhead and profit. Labor hours are a planning range and include setup, daily cleanup and material runs; they are never a charge to the customer. Permit and inspection fees are not included; requirements vary by jurisdiction.

The build in detail

A. 12x12 pressure-treated deck: $8,677

Four pier footings are poured; a flashed ledger is bolted to the house and 2x8 joists go in at 16 inches; 5/4 pressure-treated decking goes down; a wood railing runs the three open sides and one four-riser stair drops to grade. Labor is $3,943 of the $8,677 job cost, or 45.4%. It is about 48 to 69 hours of work, including setup, daily cleanup and material runs.

Labor cost by trade

Labor only. Materials, allowances and dump fees are in the line items below. Hours are person-hours at typical production from Clamp’s labor hours catalog, as a range: a planning figure, not a schedule and not a charge to the customer.

TradeHoursLabor costLow-Overhead×1.30Established×1.50Full-Service×2.00
Carpentry41 to 61 h$3,943$5,126$5,915$7,886
Setup, cleanup and material runs3 to 12 hin the prices
All labor48 to 69 h$3,943$5,126$5,915$7,886

Every line item

Labor $3,943 + materials and allowances $3,434 + dump fees and other $1,300 = $8,677 direct job cost. Hours are person-hours at typical production, on labor rows only, and the direct-cost row adds about 15% for setup, daily cleanup and material runs; an allowance or material row names the labor line that installs it, and a subcontract row has none, because the sub’s price includes their own time. Some labor quantities include a difficulty factor, so they can exceed the measured area; each row’s derivation is in the downloadable data.

ItemQtyUnitHoursLaborMaterialLine cost
Carpentry
Deck Decking Install Labor144sf7 to 16 h$936$0$936
Deck Framing Labor144sf8 to 18 h$1,044$0$1,044
Deck Materials AllowanceLabor on: Deck Framing Labor144sf$0$1,116$1,116
Deck Pier Footing4ea$0$0$1,300
Deck Railing Install Labor44.4lf11 to 24 h$1,243$0$1,243
Deck Railing Materials AllowanceLabor on: Deck Railing Install Labor46.62lf$0$2,098$2,098
Deck Stair Build (per step)4ea5 to 12 h$720$0$720
Deck Stair Materials (per step)Labor on: Deck Stair Build (per step)4ea$0$220$220
Carpentry subtotal41 to 61 h$8,677
Carpentry subtotal41 to 61 h$8,677
DIRECT JOB COST48 to 69 h$8,677
DIRECT JOB COST48 to 69 h$8,677

Methodology & reproducibility

One reviewed snapshot for this build. The build is frozen from its own estimate run and priced by the published pricer.

Direct cost equals the sum of each row’s rounded quantity × (labor + material + other). Amounts are shown in whole dollars; every column adds to its total.

Scope selection, prose accuracy, arithmetic and provenance mapping reviewed; not independent market-rate verification.

Questions

Why is the railing so much of the cost?

A 12x12 deck has 36 feet of open edge plus stair rails, and railing is slow, fussy carpentry. On a small deck the railing can cost more than the decking, which surprises homeowners who price decks by the square foot.

What can push this job higher?

Composite decking, a taller deck that needs bracing and longer posts, a deck more than 30 inches up on more sides, poor soil that needs deeper footings, or a second stair. Each is its own line.

Is the markup on top of this?

Yes. Direct job cost is what the deck costs a contractor to build. The markup table shows what it sells for at illustrative markups of 30% to 100%.

Related

Sources & provenance

  1. 12x12 pressure-treated deck reviewed snapshot Clamp Research
Changes: Oct 12, 2026: Initial publication: reviewed snapshot frozen from a fresh estimate run, priced on the current baseline.; Oct 12, 2026: Added the app screenshot pair: the job described, then the draft by trade.