Retaining walls
Overview of residential retaining walls in Australia. See the full guide: approval thresholds, AS 4678 design, drainage, and common failure modes.
Ask Chalkline about this →This page is a short pointer. The full guide lives at Retaining walls: residential.
What’s covered in the full guide
The canonical article covers everything a residential builder needs:
- Approval thresholds by state (NSW, VIC, QLD, WA) for exempt, CDC, and DA pathways
- When an engineer is mandatory (AS 4678:2002 triggers: over 800 mm, surcharge loading, boundary proximity)
- Wall types compared (concrete sleeper, timber sleeper, block masonry, gabion) with indicative cost ranges
- Drainage design (aggregate zone, ag-drain, geotextile, weep holes) and why water is the leading failure cause
- Surcharge load assessment (driveways, footings, pools near the wall)
- DCP setback rules and council-specific controls
- Common failure modes and how to prevent them
Go to the full article: Retaining walls: residential guide.
Quick-reference thresholds
| State | Exempt below | Permit / CDC above |
|---|---|---|
| NSW | 600 mm (conditions apply) | CDC or DA |
| VIC | 1 m (conditions apply) | Building permit |
| QLD | 1 m (no surcharge, 1.5 m from structures) | Building approval |
| WA | 500 mm (conditions apply) | Permit required |
Engineer design under AS 4678:2002 is mandatory for any wall over 800 mm or with surcharge loading, regardless of state.
For the full step-by-step procedure, approval conditions, drainage specs, and document checklist, see Retaining walls: residential guide.