The surface boards on a deck are 22% to 34% of what you pay for it, and almost every homeowner I quote thinks they're 70%. That gap is why a guy who priced composite decking at $4.80 a linear foot at the home center walks into a $24,000 bid for a 320-square-foot deck and assumes he's being robbed. He isn't. Here's the deal: deck building cost in 2026 runs $30 to $75 per square foot installed, and the framing, footings, ledger, hardware, railing, and stairs underneath that pretty surface are where the money lives. Pressure-treated lands at $30 to $45. Capped composite runs $45 to $75. PVC runs $60 to $95. I've built decks for 25 years, and the ones that fail always failed below the boards.
Decking Material Cost Per Square Foot, Installed
These are all-in installed numbers for a standard elevated deck — framing, footings, decking, and basic railing included. Materials alone are roughly 40% to 48% of each figure.
Pressure-Treated Pine: $30 to $45 Per Square Foot
Still about 55% of decks built in the U.S. 5/4x6 ground-contact PT decking runs $2.20 to $3.60 per linear foot at the yard, which is $4.80 to $7.90 per square foot of deck surface once you account for the 1/8-inch gap and 12% to 15% waste. The framing lumber under it is another $6 to $10 per square foot.
PT is cheap up front and expensive over time. Real-world service life on a PT deck surface is 12 to 18 years, and you're staining or sealing every 2 to 3 years at $1.20 to $2.50 per square foot. Over a 25-year window, a 320-square-foot PT deck costs about $11,200 to build and $4,600 to $8,000 to maintain. Framing lumber pricing drives a big share of that build number — our look at lumber at $487/MBF in 2026 covers where dimensional stock sits this season.
Cedar and Redwood: $35 to $58 Per Square Foot
Western red cedar decking runs $3.60 to $6.40 per linear foot. It's lighter, it doesn't splinter like PT, and it smells like a job worth doing. Life expectancy is 15 to 20 years with annual attention. Redwood is regionally priced — under $5.00 a linear foot in Northern California, $7.50-plus east of the Rockies once freight loads in.
Capped Composite: $45 to $75 Per Square Foot
Composite — wood flour and polyethylene with a co-extruded polymer cap — is now roughly 30% of the market and climbing about 3 points a year. Board cost runs $4.40 to $9.60 per linear foot depending on line: entry-grade uncapped or single-cap at the low end, multi-tone premium boards at the top.
The cap is the whole story. First-generation uncapped composite from the 2000s mildewed and faded badly and gave the category a reputation it's still shaking. Capped boards carry 25-to-30-year fade-and-stain warranties, and the real-world surface life is 25 to 30 years with nothing but a wash. Zero staining. That's the trade: pay 50% more up front, spend nothing after.
PVC and Aluminum: $60 to $95 Per Square Foot
Full PVC decking — no wood content at all — runs $6.80 to $12.50 per linear foot. It's the lightest option, the most heat-stable in direct sun, and completely immune to rot and insects. Life expectancy is 30 to 50 years. Aluminum decking runs $14 to $22 per linear foot and is mostly a rooftop and fire-zone product.
Ipe and Tropical Hardwood: $55 to $90 Per Square Foot
Ipe at $7.50 to $13.00 per linear foot is the best-looking deck surface money buys and the most miserable to install. It's so dense you pre-drill every fastener, which adds 40% to 60% to install labor. It lasts 40-plus years. It also weighs 69 pounds per cubic foot, so the framing has to be designed for it.
The Cost Table: Deck Size Versus Material
Here's what full builds total in 2026 for a standard 3-to-4-foot-elevated deck with a ledger, railing on three sides, and one set of stairs.
| Deck Size | Square Feet | Pressure-Treated | Cedar | Capped Composite | PVC |
|---|---|---|---|---|---|
| 10x12 | 120 | $3,600-$5,400 | $4,200-$7,000 | $5,400-$9,000 | $7,200-$11,400 |
| 12x16 | 192 | $5,800-$8,600 | $6,700-$11,100 | $8,600-$14,400 | $11,500-$18,200 |
| 16x20 | 320 | $9,600-$14,400 | $11,200-$18,600 | $14,400-$24,000 | $19,200-$30,400 |
| 20x20 | 400 | $12,000-$18,000 | $14,000-$23,200 | $18,000-$30,000 | $24,000-$38,000 |
| 20x24 | 480 | $14,400-$21,600 | $16,800-$27,800 | $21,600-$36,000 | $28,800-$45,600 |
| 24x30 | 720 | $21,600-$32,400 | $25,200-$41,800 | $32,400-$54,000 | $43,200-$68,400 |
Elevation changes these numbers hard. A deck 8 feet off the ground rather than 3 costs 18% to 30% more — taller posts, larger footings, mandatory bracing, guardrail on every side, and a longer stair run. A deck over 30 inches high legally requires a guardrail; a deck over about 8 feet often needs a stamped design in stricter jurisdictions.
What's Under the Boards: The 66% Nobody Prices
Footings and Posts: $250 to $700 Each
Every footing is a hole, a form tube, concrete, and a post base. A 12-inch-diameter footing 42 inches deep takes about 0.26 cubic yards of concrete. Hand-dug with a bagged mix, a footing costs $250 to $400 installed. Machine-augered with ready-mix, $180 to $300. Helical piles, which are the answer in expansive clay or where you can't get a machine in, run $450 to $900 each.
A 16x20 deck typically takes 9 to 12 footings. Frost depth sets the price: 12 inches in Georgia versus 48 to 60 inches in Minnesota is a $1,400 to $2,600 swing on the same deck. Size your pour with the concrete calculator so you're not making a second run for two more bags at 4 p.m.
Framing: $9 to $17 Per Square Foot
Joists at 16-inch centers (12-inch if you're running boards diagonally or using certain composites), a doubled or tripled beam, joist hangers, and structural screws. Ground-contact-rated PT is required for anything within 6 inches of soil, and it costs 12% to 20% more than above-ground PT.
Hardware is not a rounding error. A properly built 320-square-foot deck carries $700 to $1,400 in hangers, structural screws, hurricane ties, and hot-dipped or stainless connectors. Galvanized hardware in contact with modern ACQ-treated lumber corrodes — you need G185 hot-dip or stainless, and stainless costs 3x to 4x. On a coastal job it isn't optional.
The Ledger: $400 to $1,800, and the #1 Failure Point
The ledger is the board bolted to the house that carries half your deck load. According to CPSC and building-industry failure analysis, the large majority of catastrophic deck collapses are ledger failures — usually a ledger nailed instead of bolted, or one lacking flashing, so the rim joist behind it rotted quietly for a decade.
Doing it right means through-bolts or structural screws on a specified pattern, a metal flashing cap, and often lateral load connectors tying the deck frame back into the house floor system. That's $400 to $1,800 depending on siding type and access. A freestanding deck skips the ledger entirely but adds 2 to 4 footings and a beam, costing $900 to $2,400 more — on stone, stucco, or brick veneer, freestanding is usually the smarter build.
Want to check a contractor's takeoff against your own? Run your dimensions through our deck calculator and cross-check the framing package with the lumber calculator.
Railings, Stairs, and Permits
Railings: $60 to $220 Per Linear Foot
Railing is the single most underestimated line item on a deck bid. Pressure-treated wood railing runs $60 to $95 per linear foot installed. Composite railing runs $95 to $150. Aluminum runs $105 to $175. Cable rail runs $160 to $220, and glass panel runs $200 to $350.
Do the math on a 16x20 deck with railing on three sides: that's 52 linear feet. At composite pricing, $4,900 to $7,800 — 25% to 33% of the entire project, for the railing alone. Code requires 36-inch height residentially (42 inches in some jurisdictions), a 4-inch sphere rule on baluster spacing, and 200 pounds of concentrated load resistance at the top rail.
Stairs: $150 to $320 Per Step
A step means one tread across the full stair width plus its share of stringers, risers, and hardware. Four steps down from a 3-foot deck runs $600 to $1,280. A 12-step run from an 8-foot deck runs $1,800 to $3,840, plus a landing pad ($350 to $900) and a graspable handrail ($30 to $60 per linear foot). Stairs over a certain rise need an intermediate landing, which doubles the framing at that point.
Permits and Inspections: $150 to $900
Nearly every jurisdiction permits decks over 30 inches high or over 200 square feet, and many permit all attached decks regardless of size. Fees run $150 to $500 typically, $500 to $900 in high-cost metros, and inspections cover footings before pour and framing before decking goes down. Skipping the permit means an unpermitted structure on your property that appraisers flag and insurers can decline to cover after a collapse. It also means a footing inspection you can't pass later without excavating.
If you're pricing multiple outdoor projects this year, deck numbers rhyme with what fence installation costs in 2026 — both are footing-and-post work where frost depth and access drive more of the price than the visible material does.
Frequently Asked Questions
How much does a 16x20 deck cost in 2026?
320 square feet at $30 to $75 per square foot puts a 16x20 deck at $9,600 to $24,000 installed. Pressure-treated with wood railing lands at $9,600 to $14,400; capped composite with composite railing runs $14,400 to $24,000; PVC with aluminum or cable railing runs $19,200 to $30,400. Elevation above 4 feet, a long stair run, or premium railing pushes you toward the top of each band.
Is composite decking worth the extra cost over pressure-treated?
Over a 25-year hold, usually yes. A 320-square-foot PT deck costs about $11,200 to build plus $4,600 to $8,000 in stain and seal cycles every 2 to 3 years, and the surface needs replacing around year 15. Capped composite costs about $19,000 to build and roughly $600 in soap and water over the same period, with the surface still under warranty at year 25. If you're selling within 5 to 7 years, PT is the better financial call.
What is the cheapest way to build a deck?
A ground-level, freestanding pressure-treated deck under 30 inches high with no railing and no stairs. Dropping below that 30-inch threshold eliminates the guardrail requirement, which is 25% to 33% of a typical deck budget, and often eliminates the permit. A 12x16 ground-level PT platform runs $18 to $28 per square foot, or $3,500 to $5,400, against $5,800 to $8,600 for the same deck elevated.
How long does a deck last?
Pressure-treated surfaces last 12 to 18 years with regular sealing. Cedar lasts 15 to 20. Capped composite lasts 25 to 30. PVC lasts 30 to 50. Ipe lasts 40-plus. But the frame usually outlives the surface: properly detailed ground-contact PT framing with stainless or G185 hardware and good flashing lasts 25 to 35 years, which is why re-decking an existing frame runs $16 to $32 per square foot instead of full replacement pricing.
Do I need a permit to build a deck?
In most jurisdictions, yes, if the deck is attached to the house, exceeds 30 inches above grade, or exceeds 200 square feet. Fees are $150 to $900. Inspections typically hit twice — footings before the pour, framing before decking. Freestanding ground-level platforms under those thresholds are commonly exempt, but confirm with your building department, because the specific trigger varies more between towns than almost any other residential code item.
Why are deck bids so far apart?
Because bidders scope differently below the surface. The three places bids diverge: footing count and depth (9 footings versus 12 changes the price by $1,200-plus), hardware grade (G185 hot-dip versus standard galvanized is a several-hundred-dollar line that also decides whether your connectors survive treated lumber), and ledger detailing versus freestanding framing. Ask every bidder for footing count and depth, hardware spec, and railing linear footage in writing. Once those three match, the bids will be within 10% of each other.
Your Action Item for This Week
Measure two things this week. First, the height from your finished deck surface down to grade at the highest point. If that number is over 30 inches, guardrail is code-required, and you should add 25% to 33% to whatever square-foot number you had in your head. Second, count the linear feet of open edge — every side that isn't against the house. That's your railing footage, and at $60 to $220 a foot it's the line that decides whether your budget survives contact with the first bid.
Then call your building department and ask one question: what triggers a deck permit here, and what's the frost depth? Frost depth sets footing cost, and it varies from 12 inches to 60 inches across the country — a $1,400 to $2,600 swing on a 16x20. Two measurements and one phone call, and you'll be able to tell within 10% whether a $24,000 bid is honest or fishing.
