My Deck's Balustrade Got Flagged at Inspection. What Actually Needs to Change?

It depends on which rule it failed. Under Building Code Clause F4, a deck with a fall of 1.0m or more needs a barrier at least 1000mm high with no gap wider than 100mm, and that applies whether or not your deck needed building consent in the first place. Almost every failed inspection comes down to one of two things, and they're fixed very differently.

If the barrier is a few millimetres under 1000mm. This is the single most common fail, a balustrade built to what looks like the right height but measures short once it's finished, usually because it was measured from the wrong point or the decking added extra height that wasn't accounted for. It's usually a straightforward fix, we adjust the top rail or posts to bring it to full compliant height without rebuilding the whole barrier.

If the gaps between balusters or under the bottom rail exceed 100mm. This one's stricter to fix properly, since it's a structural and safety issue, not just a measurement. Depending on the design, it can mean adding infill balusters, replacing a panel, or in some cases redoing a section entirely if the original spacing was wrong throughout. We'll tell you honestly which situation you're in before you pay for anything.

If you're earlier in the process and want the full breakdown of when consent applies versus just the balustrade rule, our deck building rules guide covers that in detail, and Building Performance's F4 guidance has the official clause if you want to check exactly what your inspector's referencing.

If you're past that stage and just need it fixed, send us a photo of the flagged section and we'll tell you the same day which of the two situations above you're dealing with, and quote it before we start.

Frequently Asked Questions

• Can I just add a taller handrail to fix a balustrade that's too low? Sometimes, if the existing structure can take it, but if the fixings or posts weren't specced for the extra height, it often needs more than a rail swap. We check the structure first.

• Does a consent-exempt deck still have to meet the balustrade height rule? Yes. The 1.5m threshold is only about whether you needed consent to build it. The 1000mm balustrade rule applies to any deck with a 1.0m fall, consented or not.