Ask three contractors what a deck costs and you'll get three different numbers — and all of them might be right. Deck pricing swings widely based on size, materials, site conditions, and where you live. Instead of quoting you a single misleading number, let's break down where the money actually goes so you can build an estimate you trust.
The big picture
For a typical attached deck in the 200–400 square foot range, most projects land somewhere between $25 and $65 per square foot installed. The spread is driven mostly by two decisions: your decking material and who does the work.
A 12x16 (192 sq ft) pressure-treated deck built by a contractor might run $5,000–$9,000. The same footprint in composite with metal railings can reach $12,000–$18,000. Build it yourself and you can roughly cut those numbers in half — your cost becomes materials, tools, and time.
Materials: where the money goes
Framing. Pressure-treated lumber makes up the skeleton regardless of what you walk on. Posts (4x4 or 6x6), beams, joists (typically 2x8s at 16" on center), and hardware. For a mid-size deck, expect $1,200–$2,500 in framing lumber, hangers, and fasteners.
Decking surface. This is your biggest style-and-budget decision:
- Pressure-treated boards are the budget option — but they need staining every couple of years.
- Cedar costs more and looks better, with moderate upkeep.
- Composite costs the most upfront but demands almost no maintenance for decades.
Railings. Frequently underestimated. Code requires railings on decks above a certain height (commonly 30"), and railing can cost as much per linear foot as the decking costs per square foot. A composite railing kit can run $100+ per 6-foot section.
Footings and concrete. Bagged concrete is cheap; the labor of digging below frost line is not. Sites with slopes or poor access add real cost here.
Labor: the other half
Contractor labor typically accounts for 40–60% of the total price. A crew is pricing not just hours but expertise: proper ledger attachment (the #1 cause of deck failures), correct footing depth, flashing details, and code compliance.
When you review a contractor's estimate, look for labor broken out by task — demo, footings, framing, decking, railings — rather than a single lump sum. Task-level pricing tells you the contractor actually thought through your project, and it makes comparing bids meaningful.
The line items everyone forgets
These are the items that turn a $9,000 project into an $11,000 project:
- Permits — commonly $100–$500 depending on jurisdiction. Almost always required for attached decks.
- Demolition and disposal — tearing off an old deck plus a dumpster can add $500–$1,500.
- Delivery fees for lumber and materials.
- Site issues — sloped yards, buried utilities, inaccessible backyards.
- Waste factor — plan on ordering 10% extra material for cuts and mistakes.
Building your own estimate
Whether you're a contractor quoting a client or a homeowner sanity-checking bids, the process is the same: list the labor tasks with hours and rates, list the materials with quantities and current prices, add the forgotten line items above, and apply a contingency margin (10% is standard) for the surprises every project has.
That's exactly the workflow JobPencil is built around — labor by task, materials from a price catalog, a miscellaneous section for permits and dumpsters, and margins applied transparently. Build your deck estimate free, no account required, and download it as a PDF when you're done.
Prices in this article are national ballpark figures for planning purposes. Your local market may differ — always verify current material prices and get multiple quotes for contracted work.