A deck is mostly a structure you do not see: footings, posts, beams, joists, flashing at the house, and the ledger board that ties it to the building. The visible boards and railing are the smaller part of both cost and risk. Most deck failures start at the ledger or the footings, so that is where to ask questions.
Pressure-treated lumber is the lowest-cost option and needs regular sealing. Cedar looks better and costs more. Composite and PVC boards cost the most up front and ask the least of you afterward. In Zonda's 2025 Cost vs. Value report, a wood deck addition averaged $18,263 and a composite deck $25,096.
Most towns require a permit and an inspection for an attached deck. A pro who suggests skipping the permit is leaving the risk with you.
What it costs
| Item | Range | Source |
|---|---|---|
| Labor to build a deck | $11 to $22 per sq ft | HomeGuide 2026 |
| Pressure-treated decking boards | $2 to $7 per sq ft | Krueger Brothers 2022 |
| Cedar decking boards | $4 to $8 per sq ft | Krueger Brothers 2022 |
| Composite decking boards | $8 to $15 per sq ft | Krueger Brothers 2022 |
| Wood deck addition, national average job | $18,263 | Cost vs. Value 2025 |
| Composite deck addition, national average job | $25,096 | Cost vs. Value 2025 |
Deck pricing is the most scattered of the six services here, and the best public data is a mix of years and sources, so treat this as a map and not a quote. Board prices rise over time, and footings, railing, and stairs are priced separately in many bids.
What moves the price
- Size and height
- Square footage and distance above grade drive framing and railing cost.
- Board material
- Pressure-treated, cedar, composite, or PVC.
- Railing and stairs
- Often a large separate line item.
- Footings and site
- Frost depth, soil, slope, and access change labor.
- Permit and inspection
- Required in most places for attached decks.
Signs it is time
- Boards that are cupped, splintering, or soft
- A ledger board pulling away from the house or showing rust at the fasteners
- Wobbly railing or posts
- Rust or cracks in joist hangers and post connectors
- Standing water or heavy mildew that sealing no longer fixes
- Footings that heave or settle
Questions to ask a pro
- Is a permit included, and who pulls it?
- How deep are the footings, and what frost depth applies here?
- How is the ledger attached and flashed to the house?
- Which board, railing, and fastener brands, and what warranties come with them?
- What is included for stairs, lighting, and railing?
- How are changes priced if we find rot at the house wall?
Common questions
Wood or composite?
If you hate maintenance and plan to stay, composite wins on lifetime cost in many comparisons. If budget matters most now, pressure-treated with regular sealing is the lowest entry price.
Can I replace just the boards?
Often yes, if the framing is sound. Have someone check the joists, ledger, and footings first; new boards on rotten framing is money wasted.