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Rail Length

Baluster Width

Max Centre Spacing

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Flat Run Balustrade Calculator: Baluster Spacing for Decks

Calculate baluster quantities and spacing for flat (horizontal) balustrade sections on decks, verandahs, and balconies. Compliant with Australian NCC requirements.

Frequently Asked Questions

What is a flat run balustrade?

A flat run is a horizontal section of balustrade (as opposed to a raked/angled stair section). Flat runs are found on decks, balconies, verandahs, and landings: anywhere the floor is level.

What is the maximum baluster spacing on a flat run?

Under Australian NCC, the maximum gap between balusters is 125mm (a 125mm sphere must not pass through). This is measured as clear space between balusters, not centre-to-centre.

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