ウッドデッキ材計算機

Convert your deck width into inches, divide by the effective board width (actual board width + gap spacing) to get the number of board rows. Multiply rows by deck length to get total linear feet, add your waste factor (typically 10%), and divide by your chosen board length (e.g., 12 ft or 16 ft).

A standard 5/4×6 deck board has an actual milled size of 1 inch thick by 5-1/2 inches wide. A 2×6 deck board measures 1-1/2 inches thick by 5-1/2 inches wide. Always use actual dimensions when calculating row coverage and gap spacing.

For wet, green, or pressure-treated lumber right from the yard, leave an 1/8-inch gap (or butt them tight if dripping wet, as they will shrink as they dry). For kiln-dried lumber or composite decking (such as Fiberon or Trex), leave 3/16 to 1/4 inch to allow for water drainage and thermal expansion.

Standard wood decking boards (5/4x6 or 2x6) run perpendicular across joists spaced at 16 inches on-center (OC). Composite decking (Fiberon, Trex) is more flexible and typically requires 16-inch OC for perpendicular runs and 12-inch OC if boards are installed diagonally (at 45 degrees).

Plan for approximately 350 deck screws per 100 square feet of decking. Standard practice requires two fasteners at every joist intersection for 5.5-inch boards (or hidden clip systems for grooved composite boards).