Deck Building Cost Calculator
Deck Building costs $10,950 to $16,550 for a typical 320 sq ft job in 2026, against a national benchmark of $13,350. Labor runs 99.6 crew hours at $34.37 an hour. Enter a ZIP code to apply that area's measured wages for this work and its regional price level.
What makes up the price
Cost by size
National averages, before any local adjustment. Computed from the same model as the calculator above, so the two always agree.
| Deck area | Sq ft of deck | Typical | Range |
|---|---|---|---|
| 180 sq ft | 180 | $8,050 | $6,600 to $10,000 |
| 260 sq ft | 260 | $11,075 | $9,075 to $13,725 |
| 320 sq ft | 320 | $13,350 | $10,950 to $16,550 |
| 430 sq ft | 430 | $17,500 | $14,350 to $21,700 |
| 540 sq ft | 540 | $21,650 | $17,750 to $26,850 |
A deck is a structure, not a floor
This is the thing most cost guides get wrong, and it explains nearly every price on this page.
Under every square foot of decking there are joists at 16 inch centers, beams under those, posts under the beams, and a concrete footing under each post dug below the frost line. That frame is pressure-treated lumber whether the boards on top are $7 each or $17.
Two consequences follow:
The gap between wood and composite is smaller than the boards suggest. Composite boards cost two or three times what pressure-treated does, but the frame, footings, hardware and labor are identical — so the finished deck is about 40% more, not 200%.
Height costs more than any surface choice. A deck four feet up needs taller posts, bigger footings, diagonal bracing, a guard rail engineered to resist a 200 pound load in any direction, and a crew working off ladders. That is around 20% on the whole job; off a second story it is 45%.
What each part costs
For a 16x20 pressure-treated deck at ground level:
| Share | |
|---|---|
| Labor | roughly 50% |
| Frame, decking and hardware | roughly 35% |
| Permit, inspection and delivery | the rest |
By surface, the same deck:
| Decking | Typical 16x20 | Per sq ft |
|---|---|---|
| Pressure-treated | $13,350 | $42 |
| Cedar | $15,925 | $50 |
| Composite | $18,950 | $59 |
Choosing the surface
Pressure-treated
The default, and about two thirds of decks built. It is cheap, strong and available everywhere.
The cost is upkeep: it needs cleaning and sealing every two to three years, and it will check, cup and splinter if it does not get it. Let it dry for a few months before the first sealing — new treated lumber is too wet to take a finish.
Cedar
Around 20% more than treated, warmer underfoot, far less prone to splintering, and it smells like cedar. Left alone it weathers to a soft silver that many people prefer; sealed, it keeps its color.
It is softer than treated pine, so it marks more easily under furniture.
Composite
Around 40% more than treated and it never needs sealing — wash it and that is the entire maintenance program for 25 years. Modern capped composite does not fade or stain the way early generations did.
What to know before buying it:
- It gets hot. A dark composite deck in direct sun can be genuinely too hot for bare feet. Lighter colors are much better.
- It is not structural. The frame is still wood, and the frame is what eventually limits the life of the deck.
- It scratches, and the scratch cannot be sanded out the way it can in wood.
- It needs closer joist spacing than wood in some lines — 12 inch centers rather than 16 — which adds to the frame cost.
The ledger, which is what actually fails
When a deck collapses, it is almost always the ledger — the board bolted to the house that carries one whole side of the deck.
Done correctly it is through-bolted or fitted with structural screws into the house framing, flashed so water runs out rather than in, and never attached to just the siding or the rim joist veneer. Done badly it is nailed on and hidden under decking within the hour.
This is the single most important thing a deck builder does, it is invisible afterwards, and it is the detail most often skipped. Ask how the ledger is attached and flashed, and ask to see it before the decking goes down.
Freestanding decks
A deck can be built with its own posts along the house side, touching the house but not attached to it. It costs a little more in footings and removes the ledger question entirely. On an older house, or where the rim joist is suspect, it is often the right answer.
Permits and code
Decks are structural, so almost every jurisdiction requires a permit — typically $200 to $600, with a footing inspection before the concrete goes in and a framing inspection before the decking goes on.
Common requirements worth knowing:
- Guard rail above 30 inches off the ground, at 36 or 42 inches high.
- Baluster spacing such that a 4 inch sphere cannot pass.
- Stair rise and run consistent within about 3/8 inch across every step.
- Footings below the frost line, which in the north can mean four feet deep.
Unpermitted deck work is the kind that surfaces during a sale, and a deck that fails inspection after the boards are on is expensive to put right.
Does it add value
More reliably than most outdoor projects, and less than the brochures claim. Remodeling surveys consistently put deck additions among the better returning projects — typically recovering 50 to 65% of their cost at resale, with wood recovering a slightly higher percentage than composite because it costs less to begin with.
The honest framing: build a deck because you will use it. The resale return is a partial refund, not an investment.
Questions worth asking
- How is the ledger attached and flashed — or is the deck freestanding?
- How deep are the footings, and is there a footing inspection?
- What joist spacing, and does the decking require 12 inch centers?
- Is the frame pressure-treated, and are the fasteners rated for it?
- Who pulls the permit?
- What is included — stairs, railing, skirting, lighting?
Common questions
How much does it cost to build a deck?
Around $42 a square foot for pressure-treated at ground level, so about $13,350 for a 16x20 deck, with most jobs falling between $10,950 and $16,550. A 12x16 is closer to $8,500. Composite is around $59 a square foot and a second-story deck adds about 45%.
Is composite decking worth the extra cost?
Around 40% more than pressure-treated — $18,950 against $13,350 for a 16x20 — and it never needs sealing. Over 25 years that is a real saving in money and weekends. The things to weigh are that dark composite gets genuinely hot in direct sun, that scratches cannot be sanded out, and that the frame underneath is still wood and still what eventually limits the deck.
Why is composite decking only 40% more when the boards cost three times as much?
Because the boards are a minority of the job. Under them the joists, beams, posts, footings and hardware are identical pressure-treated construction, and the labor is nearly the same. The surface is roughly a third of the materials and the materials are roughly a third of the price.
Why does a raised deck cost so much more?
It is a different structure, not the same one on stilts. Taller posts, larger footings, diagonal bracing, a guard rail engineered to take a 200 pound load in any direction, stairs, and a crew working off ladders rather than off the ground. That is about 20% for a deck a few feet up and 45% off a second story.
Do I need a permit to build a deck?
Almost always, because a deck is structural. Typically $200 to $600, with a footing inspection before the concrete goes in and a framing inspection before the decking goes on. Unpermitted deck work is the kind that surfaces during a sale, and a deck that fails inspection after the boards are on is expensive to put right.
What is a ledger board and why does it matter?
The board bolted to the house that carries one whole side of the deck. When a deck collapses it is almost always the ledger. Done correctly it is through-bolted or fixed with structural screws into the house framing and flashed so water runs out rather than in; done badly it is nailed to the siding and hidden under decking within the hour. Ask how it is attached and flashed, and ask to see it before the boards go down.
How long does a deck last?
Fifteen to twenty years for pressure-treated kept sealed, twenty to thirty for cedar, and twenty-five or more for a composite surface — though in every case the frame underneath is treated lumber and is usually what sets the limit. A deck that is never cleaned or sealed can be unsafe in ten.
How long does it take to build a deck?
About 90 crew hours for a 16x20 at ground level, so roughly a week for a two-person crew, plus waiting on footing and framing inspections. Raised decks take appreciably longer because more of the work happens off ladders.
Does a deck add value to a house?
More reliably than most outdoor projects and less than the brochures claim — remodeling surveys typically put the return at 50 to 65% of cost, with wood recovering a slightly higher percentage than composite because it costs less to start with. Build it because you will use it. The resale return is a partial refund, not an investment.
Should a deck be attached to the house or freestanding?
Freestanding is worth considering on an older house or where the rim joist is suspect. It costs a little more in footings and posts and removes the ledger — the detail most likely to be done badly and the one that causes collapses — from the job entirely.
Where these numbers come from
Nothing here is copied from a contractor directory. Labor is priced from what the trades are actually paid, materials from published producer prices, and both are adjusted to your area using federal cost-of-living data.
- Finish carpentry contractors, United States: $34.37/hour, August 2026 (BLS CES CES2023835003)
- Pressure-treated frame and decking: $11.00 per sq ft (price recorded October 2026, not index-adjusted)
- Footings, hangers, flashing and fasteners: $3.50 per sq ft (price recorded October 2026, not index-adjusted)