Proper backfill prevents settlement and ensures drainage. Use 20mm free-draining gravel in the zone behind the wall (300–500mm wide).
What NOT to Use
Never use clay, organic soil, or demolition waste directly behind a wall — these hold water and increase pressure.
Combined with proper drainage, correct backfill practices ensure longevity. Browse wall types for material-specific requirements. Get quotes for professional installation.
Ready to Start Your Project?
Our free service connects Perth homeowners with WA Building Commission licensed retaining wall builders. Get free, no-obligation quotes — it’s fast, free, and there’s zero obligation.