Decks are usually quoted by the square foot, but a flat per-square-foot price hides where the time really goes: footings, railings and stairs. Break the deck into parts and price each one.
The short version. Count footings, framing, decking boards, railing feet and stair steps separately. Railings and stairs take far more time per foot than the deck surface, so give them their own lines.
1. Check permits and code first
Most areas require a permit for a new deck, especially one attached to the house or raised off the ground. Under the International Residential Code, which most states use as a base, a deck surface more than 30 inches above the ground needs a guard (railing). Your local building department has the final say on footings, ledger attachment, guards and stairs — check before you price.
2. Footings and framing
- Footings and posts: count from your layout. Depth depends on your local frost line and code.
- Ledger: if attached to the house, include the flashing and the lag screws or bolts the code calls for.
- Beams and joists: joists are commonly 16 inches on center. Composite decking and diagonal patterns often need closer spacing — check the decking manufacturer's chart.
- Hardware: joist hangers, post bases, structural screws and flashing tape add up. Count them.
3. Count the decking boards
Figure how many rows of boards cover the deck, then add waste.
Example (illustrative): a 12 × 16 ft deck, boards running the 16 ft length, 5½-inch-wide boards with a ⅛-inch gap.
| Step | Math | Result |
|---|---|---|
| Deck area | 12 × 16 | 192 sq ft |
| Board plus gap | 5.5 + 0.125 = 5.625 in | 0.469 ft |
| Rows across 12 ft | 12 ÷ 0.469 = 25.6, round up | 26 boards, 16 ft long |
| Plus about 10% waste | 26 × 1.10 = 28.6, round up | 29 boards |
| Joists at 16 in. on center | 16 ft = 192 in ÷ 16 = 12 spaces | 13 joists |
Add fasteners or hidden clips for the decking you're using, and fascia boards for the rim.
4. Railings and stairs
These are the slowest parts per foot, so price them on their own:
- Railings: by the linear foot, plus posts. Metal, cable and glass systems cost and install very differently from wood.
- Stairs: by the step. Each one needs stringers, treads, risers (if closed) and usually a handrail, plus a landing pad at the bottom.
5. Other costs to include
- Tearing out and hauling away an old deck
- Digging in rocky soil, or near utilities (call 811 before you dig)
- Getting materials into the backyard — long boards through a side gate take time
- Stain or sealer for wood decks, and when it can be applied
6. Figure the labor hours
Estimate each part, and count every person's time (two people for 4 hours is 8 labor hours). Typical hours for the 12 × 16 ft deck from above, with 40 feet of railing and a 4-step stair.
| Task | Typical labor hours |
|---|---|
| Layout, footings and posts | 6 |
| Ledger, beams and joists | 12 |
| Decking and fascia | 8 |
| Railing, 40 linear feet | 10 |
| Stairs, 4 steps | 6 |
| Total | 42 hours |
Labor cost = total hours × your hourly labor cost. Your hourly labor cost is the wage plus burden — payroll taxes, workers' comp and insurance. For example, a $28 wage plus 25% burden is $35 an hour. If you work alone, use the wage you pay yourself. The free labor rates by state tool shows typical wages for your trade and area.
42 hours × $35 = $1,470 in labor. Railings and stairs are 16 of the 42 hours — that's why they get their own lines.
These are typical hours for a straightforward job with an experienced crew. Specialty and custom design work adds hours — for example multi-level decks, curves, picture-frame borders, built-in benches or planters, and custom railings. Price those as their own lines, so the customer sees what the extra work costs. Your own times are the best guide: write down how long each task takes on every job, and your estimates get sharper each time.
7. Add overhead and profit
Add materials and labor, then apply your overhead and profit. The free markup and margin calculator does the math.
Tip: Give the customer separate prices for the deck, railings and stairs. They can see where the money goes, and they won't compare your all-in square-foot price with a competitor who left the railings out.
See also: Trades HQ for deck builders and Estimating Basics.