Deck Board Calculator
Calculate decking boards needed by deck size. Spacing and waste included. Free calculator.
Board Width and Spacing
Standard deck boards are 5.5 inches wide (nominal 1x6). Leave a 1/8-inch gap between boards for drainage and expansion — wet wood swells, and boards installed tight in summer will buckle. Composite decking needs larger gaps (3/16 to 1/4 inch) because it expands more with heat. Use a 16d nail as a spacer for wood, or the manufacturer-specific spacer clips for composites. Run boards perpendicular to joists, which should be 16 inches on center for residential decks (12 inches for composites and diagonal layouts).
Pressure-Treated vs Composite
Pressure-treated pine costs $2-4 per linear foot but needs staining every 2-3 years and may warp or crack. Over 20 years: $4,000-8,000 including maintenance. Composite (Trex, TimberTech) costs $5-10 per linear foot but needs zero staining and resists rot, insects, and warping. Over 20 years: $5,000-9,000 total — surprisingly close to treated wood when you factor in stain, labor, and replacement boards. The crossover point is around year 7 — after that, composite is cheaper cumulatively.
The most overlooked deck expense: hidden fasteners. Face-screwing is the cheapest method ($0.02/screw) but leaves visible screw heads that collect dirt and moisture. Hidden clip systems ($0.25-0.50/board-foot) create a clean surface with no visible fasteners — worth every penny on a composite deck where aesthetics matter.
