Balustrade calculator
Check the Queensland rules, count balusters and see a rough cost.
Any gap under 125 mm passes.
Your balustrade
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How does the balustrade calculator work?
Tell it where the balustrade goes, how far the drop is, and how long it runs. It checks the Queensland rules, counts the balusters for the gap you want, and works out a rough cost from What's The Damage's Gold Coast price per metre.
For balusters, it fits as many as it takes to keep every gap at or under the one you type in, then shows the real gap. Count one straight run between posts or walls at a time.
What are the balustrade rules in Queensland?
Queensland uses the National Construction Code 2022 until 1 May 2027. Part 11.3 sets these rules for houses:
| Rule | What the code says |
|---|---|
| When you need one | A drop of 1 m or more |
| Height on a deck, balcony or verandah | At least 1 m |
| Height on stairs | At least 865 mm above the treads |
| Gaps | No 125 mm ball fits through |
| Gap to the edge of the deck | No more than 40 mm |
| Drop of more than 4 m | Nothing to climb on from 150 to 760 mm up |
| Wire balustrades | Wire tensioned to Tables 11.3.6a to c |
NCC 2022 Housing Provisions, clauses 11.3.3 to 11.3.6, checked 27 October 2026.
Our balustrade height guide explains each rule in plain words.
How many balusters do I need?
Take one baluster plus one gap, and see how many fit in the run. Then check the gaps left over are under 125 mm.
For a 3 m run with 42 mm balusters and gaps of up to 100 mm, that is 21 balusters. The 22 gaps come out at about 96 mm each, so a 125 mm ball will not fit through.
What does a balustrade cost on the Gold Coast?
About $145 to $440 per metre, with $275 typical, according to What's The Damage (October 2026). Timber slats sit at the low end, from $145 a metre. Stainless wire sits in the middle to upper band and aluminium in the middle. Frameless glass is often quoted above $440 a metre.
How high does a balustrade need to be in Queensland?
At least 1 m above the floor on a deck, balcony or verandah, and at least 865 mm above the front edge of the treads on stairs. That is NCC 2022 clause 11.3.4.
What is the biggest gap allowed between balusters?
Any gap that stops a 125 mm ball. The same rule covers the gap under the bottom rail and between wires.
Does a low deck need a balustrade?
Only where the drop is 1 m or more, measured from the deck down to the ground or surface below. A deck that steps down to a sloping yard often needs one on its high side.
Planning a balustrade?
- Decks and patios on the Gold CoastNew timber and composite decks, pool decks and patios, plus repairs to the deck you have.
- Balustrade Height Rules in QLD (2026 Guide)Height, gap and climbing rules for Queensland decks and stairs.
- Timber Stairs Cost Gold Coast (2026 Prices)Stair and balustrade prices for 2026, step sizes and repair costs.
- Deck Cost per m2 on the Gold Coast (2026 Prices)Prices per square metre for pine, hardwood and composite decks.
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