Skip to content
HobbyHQ
Search

Shed building

Cladding quantity estimator

Turns wall dimensions into a board count, working from the cover width after overlap rather than the width on the price list — which is the difference that leaves people 20% short.

The question this answers: “How many boards do I actually order to clad this, and why did the last lot come up short?”

All four walls added together.

The exposed face after overlap, not the nominal width. A 125mm feather-edge board typically covers around 100mm.

Your choice rather than this tool’s. Ten is the usual starting point.

Optional. Leave at zero to skip costing.

Result

Boards to order
87
78.6 to cover the area, rounded up after a 10% allowance.
Area to clad
28.3 m²
30.8 m² of wall less 2.5 m² of openings.
Linear metres
313.2 m
What a yard pricing by the metre will quote against.
Material cost
—
Enter a board price to cost the order.

Worth knowing about this answer

  • An ordering estimate, not a specification. It says nothing about whether the structure is adequate, what fixings to use, or whether the building is permitted — those are on the page, and a wall that is cheap to clad can still be one you are not allowed to build.
  • Cover width is the exposed face after overlap, not the width printed on the price list. Ordering against nominal width is the standard way to finish a wall short, which is why this tool asks for the harder number.
Show the working
  1. Gross wall area14 m perimeter × 2.2 m high30.8 m²
  2. Less openings30.8 − 2.528.3 m²
  3. Area one board covers3.6 m × 100 mm cover0.36 m²
  4. Boards before waste28.3 ÷ 0.3678.61
  5. Plus waste, rounded up78.61 × 1.187 boards

Boards to order: 87. Area to clad: 28.3 m². Linear metres: 313.2 m. Material cost: —

How it works

Wall area is the perimeter multiplied by the height, less the area of openings. Each board covers its length multiplied by its cover width — the exposed face after overlap, converted from millimetres to metres. Dividing the net area by the area one board covers gives a board count, which is then increased by the waste allowance you chose and rounded up to a whole board.

What it assumes

  • Rectangular walls of uniform height. A gable end is entered as its own area rather than by perimeter and height.
  • Cover width is constant, which holds for shiplap and for feather edge set to a marked gauge and not for boards lapped by eye.
  • The waste allowance is the reader’s judgement and is an input for exactly that reason.

Where it stops being reliable

  • An ordering estimate and nothing else. It makes no claim about whether the structure is adequate, what fixings to use, what battens or membrane are needed, or whether the building is permitted — the last of those is on the shed building page, where the permitted development limits are quoted at their exact figures.
  • Cutting waste around many openings exceeds a flat percentage. A wall that is mostly window generates far more offcut than a plain one, and the tool warns rather than modelling it.
  • Nothing about the roof, which is a different covering, a different unit and a different calculation.

Runs entirely in your browser — nothing you type is sent anywhere. Last reviewed 2026-08-17. More on Shed building.