Methodology
Formula & assumptions
Plank courses
ceiling width ÷ installed face width, rounded up
Uses actual installed coverage per course.
Base linear stock
courses × ceiling run length
One linear run for each course.
Planning target
base linear stock × (1 + allowance)
Keeps cuts and layout reserve visible.
Whole planks / cartons
target ÷ stock length, then package rounding
Rounds first to planks and then to cartons.