Retaining Walls
By George Giannakakis · M.Arch · RLA300580 · HIA Industry Judge
Last reviewed: · How we research
Retaining Walls explained in detail
Structures built to hold back soil or rock from a building, roadway, or other infrastructure. Used in areas where the land's natural slope is too steep to support the weight of the soil or rock. Made from various materials, including concrete, stone, timber, and steel. They are often used in landscaping and gardening to create level terraces or to hold back soil in a hillside garden. Retaining walls over a certain height (typically 600mm-1m depending on state) require engineering design and council approval.
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Frequently Asked Questions
Common questions about retaining walls
Generally, retaining walls under 600mm-1m (varies by state/council) don't need approval. Higher walls typically require engineering design and building approval. Walls near boundaries, supporting structures, or affecting drainage usually need approval regardless of height. Check with your local council for specific requirements.
Cost figures are indicative onlyUpdated February 2026
All prices and cost ranges mentioned are approximate, based on Adelaide market conditions at time of writing, and may not reflect current pricing. Actual costs depend on your specific site, design, builder, materials, and market conditions. Project-specific quotes from qualified professionals are needed for accurate pricing.
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Verify against the binding rules in your state
BuildPilot is an independent home-build CoPilot - we publish guidance, we don't hold a building licence. Every Australian residential build must comply with the National Construction Code plus state-specific Acts and consumer-protection law. The authorities below are the primary sources of truth for the rules that actually apply to your project.
National
The primary national set of technical building standards that every Australian build must comply with. Volume 2 covers Class 1 & 10 buildings (most homes).
Specific material, product and method standards (e.g. AS 3700 masonry, AS 1684 timber framing) referenced by the NCC.
National peak body for residential builders. Publishes the most widely used home-building contracts and consumer guidance.
National peak body for general builders. Publishes commercial and residential contracts and industry guidance.
By state & territory
Links above open the public website of each authority. BuildPilot is not affiliated with these bodies and does not act on their behalf. Information on this page is general - check the current edition of the NCC and the relevant state Act for binding requirements.
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