How many cladding boards do I need?

Divide the wall length by the effective board width (board width minus the overlap, typically 25mm). For a 6m wall with 150mm boards and 25mm overlap, you need about 48 boards.

What spacing should I use for cladding battens?

Battens should be fixed vertically at 600mm centres (maximum) to provide adequate support. Use treated 25x50mm or 38x50mm battens. Always include horizontal battens at the top and bottom of the wall.

Do I need a membrane behind cladding?

Yes, a breathable membrane should be fitted behind the battens to protect the wall from wind-driven rain while allowing moisture vapour to escape. This is a Building Regulations requirement.

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Wall Cladding Calculator — Boards, Battens & Fixings

Calculate wall cladding boards, battens and fixings for external walls. Supports different board widths with opening deductions.

Wall Height

Standard storey height is 2.4m

Wall Length

Average length per wall

Board Width

150mm is most common for cladding

Openings to Deduct

Doors and windows

How We Calculate This

This calculator determines the number of cladding boards by dividing the wall length by the effective board width (accounting for overlap), then calculates battens and fixings.

The formula

Boards = Wall length ÷ (Board width - Overlap)
Battens = (Wall length ÷ Spacing) + 1 + 2 horizontal

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.