A 16×20 (320 sqft) deck costs $19,183–$30,186 installed in 2026, depending on material and state. The lower end is pressure-treated pine in an average-labor state; the upper end is premium hardwood in a high-labor metro. Most homeowners picking a mid-tier composite land at $25,284.
What a 16×20 deck fits
At 320 square feet, a 16×20 deck comfortably holds a large dining set, full lounge, a grill area, and room for a hot tub or fire table.
For perspective: a 4-person round dining table needs about 80 sqft clear space. A standard outdoor couch plus coffee table needs 50–70 sqft. A built-in grill station needs 20–30 sqft plus clearance. Add 6 feet of circulation paths on active sides.
Cost by material — 16×20 deck (US average)
Mid-height (4–6 ft) build, composite balusters, one stair run, permit, 8% contingency. Baseline uses a national average labor rate.
Pressure-Treated Pine
15–20 yrs · Stain every 2–3 yrs
$60/sqft
$19,183
Cedar / Redwood
20–25 yrs · Seal every 2–3 yrs
$67/sqft
$21,495
Composite (Trex, TimberTech)
25–30 yrs · Rinse yearly
$79/sqft
$25,284
PVC / Cellular
30+ yrs · Rinse yearly
$88/sqft
$28,178
Ipe / Cumaru Hardwood
40+ yrs · Oil annually (optional)
$94/sqft
$30,186
16×20 composite deck cost by state
Same 320 sqft composite build, state-by-state. Metro labor can shift these another ±5–15%.
A 16×20 (320 sqft) deck costs $19,183–$30,186 installed in 2026. Pressure-treated pine is the cheapest at ~$60/sqft; composite (Trex, TimberTech) runs ~$79/sqft; premium hardwood (ipe) runs up to ~$94/sqft. Labor is 40–55% of the total.
Can I build a 16×20 deck myself?+
Possibly, but a 16×20 deck at 320 sqft is on the larger side for DIY. Framing, ledger attachment, and stair construction are code-critical steps many jurisdictions require to be inspected. Expect to save 40–55% on labor if you're capable; add 10–15% to material budget for wasted cuts and mistakes.
Do I need a permit for a 16×20 deck?+
Yes in nearly all US jurisdictions. Decks over 30 inches off the ground or attached to the house require a building permit and at least a footing and final inspection. Permit costs typically run $100–$500; a 320 sqft deck lands in the middle of that range.
How long does a 16×20 deck take to build?+
3–4 weeks of active build time for a crew of 2–3 once permits are approved. Permit approval itself adds 2–6 weeks upfront. Composite and PVC installs run slightly faster than wood; multi-level or wraparound designs add another 1–2 weeks.
What shape should a 16×20 deck be?+
Rectangle is the cheapest and fastest to build. L-shape adds 10–15% cost but wraps around corners well. For footprints where 16×20 is the bounding box, check what fits inside — an L-shape or wraparound at a 16×20 envelope will have less actual deck surface than a solid 320 sqft rectangle.
Price your own 16×20 deck
Use the calculator to adjust material, shape, height, railing, and features for your state.