How this calculator works
Boards cover wall width with gaps only between adjacent boards. One batten covers each internal joint; perimeter pieces are counted as trim. The purchase estimate keeps full-height board and batten lengths even where openings reduce net area, because opening positions and offcut reuse are unknown. Furring length equals wall width times the entered number of rows.
Formula
Boards = ceil((wall width + gap) / (board width + gap)); battens = boards - 1; wall width = boards x board width + (boards - 1) x gap; net area = width x height - openings.
Worked example
Ten boards 100 mm wide with nine 10 mm gaps span 1.09 m. At 2 m height they require 20 m of boards, 18 m of battens and 3.27 m of furring for three rows.
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Frequently asked questions
Why do openings not reduce the board count?
A small window still interrupts full-height boards. Without opening positions and a cutting plan, subtracting opening area from a stock count can leave you short.
How wide should a batten be?
It must cover the board gap plus the overlap required by the chosen cladding system. This tool only checks that it is wider than the gap.
Are the board sizes nominal?
Enter actual face widths. Surfaced lumber is smaller than its nominal trade dimensions; consult the supplier or CWC size table.