Decking for a 16×20 Deck
A 16×20 deck is 320 sq ft — about 49 pressure-treated boards (5.5"×16') plus 4 box of deck screws. Adjust board size below for composite or wider boards.
Deck boards
49 boards
Deck area
320 sq ft
Decking boards
49 boards5.5"-wide × 16' PT, incl. 10% waste
Deck screws
4 boxes~1,120 screws (≈3.5/sq ft)
Decking cost (est.)
$1,120~$3.50/sq ft pressure-treated
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How this is calculated
Mulch volume = bed area × depth. We convert cubic feet to cubic yards for bulk delivery and to 2-cu-ft bags for the bagged option, so you can compare cost both ways.