Yes, in most cases, if your wall is over roughly 1 metre high, supports a structure, driveway or pool, or sits near a boundary. Below that threshold requirements vary by state and council, but engineering is still recommended for safety.
The short answer: if your wall is over roughly 1 metre high, supports a structure, driveway or pool, or sits near a boundary, you almost certainly need a structural engineer — regardless of what state you're in. Below that, requirements vary, but engineering is still recommended for safety.
Why height matters
Wall height dramatically increases the forces a retaining wall must resist. A 400mm garden edge and a 1.8m boundary wall are entirely different engineering problems — the taller wall needs proper footing design, drainage and often reinforcement to avoid failure.
Surcharge changes the calculation
Even a low wall can need engineering if it's supporting extra load above it — a driveway, a pool, a shed or parked cars all count as surcharge, and this can trigger a requirement for engineering regardless of the wall's height.
State-specific requirements
Exact thresholds and approval pathways differ by state and council — see our Council Approval & Compliance page for a general overview, or contact us to confirm what applies to your specific site.
When in doubt, ask
Getting a quick opinion before you build is far cheaper than retrofitting compliance — or dealing with a wall that fails — after the fact.