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Cladding Coverage CalculatorTimber Cladding Coverage Calculator

Estimate the linear metres and number of cladding boards for any wall, working in effective cover width for shiplap, tongue-and-groove, featheredge and board-and-batten profiles. Deducts openings and adds waste.

Net Wall AreaEffective CoverLinear + Board Count5 ProfilesPDF Report
CC

Cladding Coverage Calculator

Timber Cladding Coverage Calculator

Wall Area
mm
mm
m2

Total door + window area.

Cladding Board
mm

Exposed width after overlap. Auto-set by profile.

mm
%
OK
Cladding Coverage Results
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m2
Net Area
-
metres
Linear Required
-
boards
Boards Needed
-
courses
Board Rows
MetricValueDetail
Cladding Calculation
About Cladding Coverage Calculator
Timber cladding boards overlap or interlock, so the width they actually cover on the wall (the effective cover) is less than the board's full width. This calculator works in effective cover to give an accurate count of linear metres and boards for any wall, after deducting openings and adding a waste allowance - so you order the right amount of shiplap, tongue-and-groove or featheredge.
Where Is This Used?
External CladdingFacade WorkTimber SidingMaterial EstimationRenovation QuotesGarden Buildings
Formulas Used
Net area = (Wall width x height) - OpeningsLinear m per m2 = 1000 / Effective cover width (mm)Total linear = Net area x Linear per m2 x (1 + waste%)Boards = ceil(Total linear / Board length)Courses = ceil(Wall height / Effective cover)
Frequently Asked Questions
What is effective cover width?
It is the visible, weather-exposed width of a board once installed - after the overlap (shiplap, featheredge) or the tongue hidden in the groove (T&G) is subtracted. A 150mm shiplap board might only cover 125mm. Always estimate cladding on effective cover, never the full board width, or you will fall short.
How much waste should I allow for cladding?
10% is a sensible default for straight walls. Increase to 15% for walls with many openings, diagonal or herringbone patterns, short runs that create more offcuts, or if you want matched lengths. End cuts at openings and corners are the main source of waste.
Should cladding run horizontally or vertically?
Both are used. Horizontal (the default here) sheds water naturally and is the traditional look. Vertical cladding (board and batten, or T&G on battens) needs horizontal battens behind it for fixing and drainage, and is good for a contemporary look - but check the cover direction matches how you measure the wall.
ResourcesView the formulasFormula Library
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