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. Upload a backyard photo. Use any phone photo of the build site. No measurements, no CAD file.
2. Mark the deck area. Drag to outline where the deck goes. Add stairs or a railing line if you want them.
3. Choose material and design. Pick composite, PVC, cedar, or pressure-treated. Compare looks on the same photo.
4. Generate the render and share. Get a photorealistic render in seconds. Send it to the homeowner or attach it to a proposal.

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 — 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.

Ranges are 2026 North American installed averages (materials plus contractor labor). Raised two-zone builds with stairs and full railing typically land mid-range to upper; ground-level versions can dip below.

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?

Remodeling-cost studies consistently put wood and composite decks among the better exterior returns — commonly recouping half to three-quarters of cost at sale, more in outdoor-living markets. The honest version: a well-proportioned deck photographs well in listings, and 16×20 photographs like a room.

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.