Calculated estimate20
boards
Shiplap stock boards to buy
Horizontal courses per wall18 courses
Visible final-course width2.5 in
Stock pieces per course1 piece
Pieces before allowance18 boards
Total course-run footage216 linear ft
Wall face area96 sq ft
Purchased stock footage240 linear ft
The board count conservatively assumes each course receives whole stock pieces and does not credit offcut reuse. Calculate unequal walls separately and follow product instructions for gaps, fastening, joints, and acclimation.