When you’re planning alterations or extensions to an existing building in Victoria, one regulation you can’t afford to overlook is Regulation 233. With nearly two decades in the building and construction industry — including time spent as both an architectural drafter and a registered building surveyor — I’ve seen how this regulation can impact projects large and small. It’s an area where the right advice early on can save time, money, and frustration down the track.
When Does Regulation 233 Apply?
Regulation 233 applies to building work involving alterations or extensions to existing structures. Its purpose is to ensure that when significant changes are made to a building, the work — and in some cases the entire building — meets the current Building Regulations and National Construction Code (NCC). This protects not only the structural integrity and safety of the building, but also its amenities and functionality. In simple terms, if you’re adding to or altering an existing building, this regulation makes sure the whole structure remains safe and up to today’s standards.
A key trigger under Regulation 233 relates to volume thresholds. If the total volume of your planned alterations — combined with any other alterations carried out in the past three years — exceeds 50% of the original building volume, the entire building must be brought into full compliance with current regulations. If your works stay under this threshold, only the new or altered parts must meet today’s code. But even then, the relevant building surveyor (RBS) has discretion to allow or require additional compliance depending on the specifics of the project.
Extensions come with their own specific requirements under this regulation. If the new floor area exceeds 25% of the existing floor area or 1,000m² (whichever is less), the RBS cannot approve a partial compliance pathway for that new work. However, for smaller extensions, partial compliance may be possible if safety and structure requirements are still fully satisfied.
Why Getting It Right Matters
Failing to meet your obligations under Regulation 233 can lead to serious issues: delays in permit approvals, costly redesigns, or even legal notices requiring mandatory rectification work. I’ve seen many projects where early, expert advice on these thresholds would have saved time, stress, and budget blowouts. That’s why working with a qualified, experienced building surveying team like mine is so important. We know how to interpret these rules practically and ensure that your project stays compliant without unnecessary overreach or risk.
Your Partner in Achieving Compliance
With nearly 20 years of industry experience — across design, construction, compliance, and project management — I’ve built Deemed To Perform Consulting to help clients confidently navigate complex building regulations like Regulation 233. Whether you’re a builder, designer, or property owner, my team and I can guide you through the process, ensuring you understand your obligations, avoid pitfalls, and achieve a smooth building permit pathway.
If you’re planning an alteration or extension and want to be sure your project meets Regulation 233 requirements, get in touch today. You can reach us on 0404 300 268 or email hello@deemedtoperform.com.au. Let’s make your next project compliant, efficient, and successful.
