How boards are counted
Deck boards run one direction — usually along the long side and parallel to the house — so the number you need comes from the width: divide it by the board width plus its drainage gap, and round up to a whole board. The classic pressure-treated "six-inch" board actually measures 5½ inches, and gaps of ¼ inch are typical for wood (composites often want the manufacturer's own figure), which is why a nominal 12-foot width takes 26 boards rather than 24.
Screws and what the price covers
The screw estimate runs about 350 fasteners per 100 square feet, matching two screws per joist crossing on 16-inch centers. Board cost multiplies your per-board price by the count, assuming each board is cut from a length matching the deck — boards are sold in fixed lengths like 8, 12, and 16 feet, so real shopping lists jump to the next available length and generate offcuts. The frame beneath, hardware, and railing are separate line items entirely.
Frequently Asked Questions
What board size is standard?
Five and a half inches wide is the face of a nominal 1×6 or 5/4×6 board, the most common decking in North America. Composites and PVC come in similar widths, but check the label — a tenth of an inch per board shifts the count on wide decks.
Why leave gaps between boards?
Gaps let rain drain and boards shed swelling without buckling. Wood shrinks after installation so tight-laid pressure treated often gaps itself, but composites never shrink — their spacing is permanent from day one.
Does the estimate include the frame and railing?
No. Joists, beams, posts, hardware, railing, and stairs typically add 50–100% to the decking bill, and labor on a pro build usually rivals the material total.