16×20 Deck Cost

Why this page exists

The two-zone standard

At 16×20 the deck stops being furniture-with-a-floor and becomes rooms: dining by the door, lounge at the rail, walk line between.

Installed ranges, real math

Pressure-treated, composite, and PVC for exactly 320 sq ft, the same numbers our cost calculator and widget publish.

The best-documented size

Our material calculator’s worked examples use this exact footprint, so every quantity here cross-checks against the estimating page.

Big decks deserve a preview

At this scale the deck defines the backyard. Render it on your own photo, material by material, before the design locks.

How it works

1. Show us your space. Upload a clear backyard photo. Tell us where the deck should go and what you want to change.
2. Check your brief. Review your photo and choices, then buy your Deck Ideas Pack for US$19. No subscription.
3. Compare and refine. Explore three concepts. Use your two remaining refinements to develop a favorite.
4. Take the next step. Download clean images and compare before and after. Share your ideas with family or a builder.

16×20 Deck Cost

The direct answer: a 16×20 (320 sq ft) deck costs about $8,000 – $12,800 installed in pressure-treated pine, $14,400 – $22,400 in composite, or $19,200 – $28,800 in PVC. This is the size where a deck earns the phrase “outdoor room” honestly (full dining and full lounging with circulation between), and where per-square-foot pricing settles into the market’s mid-band, because crews build it constantly.

Installed cost by material

What the build takes

What moves the price

• Zones set the budget rhythm. Dining zone at the door, lounge at the far rail, grill off the walk line. Getting the zone plan right on a render first prevents the expensive version of the conversation, the one that happens after framing.
• Railing and stairs at scale. A raised 16×20 carries about 52 feet of railing plus a stair run. In premium rail systems that package alone can pass $5,000. It’s the most common surprise in bids at this size.
• Material spread widens. The pressure-treated-to-composite gap on 320 sq ft is roughly $6,400–$9,600 installed. Big decks make the maintenance argument louder too: staining 320 sq ft is a real weekend, every other year, forever.
• Crew familiarity. Like the 12×16, this size gets quoted weekly by any established deck builder. Use that: bids should cluster, and the quantities table below gives you the line items to compare them on.

U.S. planning allowances in USD for a simple, single-level deck, including ordinary materials and contractor labor. These are PaperPlan editorial assumptions, not surveyed averages or a local quote. Stairs, railing and elevated or complex framing need separate quotes; see the scope and sources below.

Fastener benchmark: Trex Hideaway Universal clip coverage. Check the fastener system and joist spacing for your chosen boards.

Cost assumptions and sources

U.S. planning allowances in USD for a simple, single-level deck, including ordinary materials and contractor labor. These are PaperPlan editorial assumptions, not surveyed averages or a local quote.

• Pressure-treated: $25 – $40 / sq ft installed (USD)
• Composite: $45 – $70 / sq ft installed (USD)
• PVC: $60 – $90 / sq ft installed (USD)

Multiply deck area (width × length in feet) by the selected installed rate, then round each end of the range to the nearest $100.

Demolition, permits and engineering, taxes, stairs, railing, roofs, unusual foundations and difficult site access need separate quotes. Location, product selection and labor can put a real bid outside these ranges. Canadian projects need local CAD pricing.

The manufacturer sources below explain scope and cost drivers; they do not validate PaperPlan’s exact installed-rate bands. Supplier material estimates should not be compared directly with an installed project budget.

• Trex: deck material cost calculator: Estimates materials and explicitly excludes labor; prices vary with location, season and design.
• TimberTech: understanding deck costs: Separates decking, railing, labor and substructure, and explains the impact of site and project features.

Sources and assumptions reviewed 2026-09-09. Confirm the scope and current price with local contractors before budgeting a build.

Common questions

How many joists does a 16x20 deck need?

About 16 joists on 16-inch centers, each spanning the 16 ft depth (typically broken over a mid-beam), or 21 on 12-inch centers for diagonal or heavier decking, the same math as our deck material calculator’s worked example.

How much railing does a 16x20 deck take?

Roughly 52 linear feet against the house on its long side (both 16 ft sides plus the outer 20 ft run) minus the stair opening. Railing choice moves this line item more than any other: aluminum balusters, composite rail, and cable can differ by 3× per foot.

Does a 16x20 deck add resale value?

Resale value depends on the local market, condition, design and buyer priorities. This cost model does not estimate resale return; ask a local real estate professional about comparable homes before treating the project as an investment.

What layout works on 320 sq ft?

The classic: six-to-eight-person dining nearest the kitchen door, lounge seating at the far rail where the view is, grill on the short side out of the walk line. Render your actual furniture on your actual yard and the layout argument usually ends itself.