16 × 20 deck cost & materials
Short answer
A 16 × 20 ft deck is 320 square feet. In composite it costs about $9,600–$19,200 installed and needs roughly 49 deck boards and 16 joists.
Area
320 sq ft
Composite cost
$9,600–$19,200
Deck boards
49
Joists
16
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Frequently asked questions
How many deck boards for a 16 × 20 deck?
About 49 16-ft boards (5½" wide) for 320 sq ft, including 10% waste. Longer boards mean fewer pieces but more offcuts.
How much does a 16 × 20 deck cost?
A composite 16 × 20 deck costs about $9,600–$19,200 installed. Pressure-treated wood is cheaper; PVC costs more.
How many joists for a 16 × 20 deck?
About 16 joists at 16" on center, plus 8 footings. Enter your exact size and spacing in the calculator.