15-20mm Crushed Concrete Drainage Metal

Strong, versatile mid-size drainage metal for civil, commercial & landscaping projects

Our 15-20mm crushed concrete drainage metal is a high-performing recycled aggregate ideal for general drainage, trenching, backfilling, and infrastructure projects. Made from cleaned, screened, and crushed recycled concrete, this size provides excellent drainage capability with added mass and stability compared to smaller grades.

Sized between 15mm and 20mm, this is a popular drainage metal for contractors who need reliable flow combined with structural performance, especially in deeper trenches or high-load environments.

Typical Applications

  • Drainage trenches for civil, residential, and farm works
  • Pipe bedding for medium to large stormwater and sewer lines
  • Retaining wall drainage zones
  • Backfill in civil projects where drainage and stability matter
  • Soak pits & stormwater management systems
  • Foundation and under-slab drainage layers
  • Rural driveways & farm races where a slightly coarser drainage metal performs best


The 15-20mm size is a true multi-purpose drainage aggregate used widely across NZ construction.

Why Choose 15-20mm Recycled Crushed Concrete Drainage Metal?

✔ High Drainage Efficiency

The coarser size creates wide, stable flow channels for long-term water movement.

✔ Added Bulk & Stability

Ideal for deeper trenches or areas requiring more structural presence than finer drainage metal.

✔ Sustainable NZ Construction Material

Recycled crushed concrete supports waste reduction and reduces reliance on virgin quarry products.

✔ Strong, Angular Particle Shape

Optimizes interlock, stability, and bedding strength while remaining free-draining.

✔ Produced Locally, Delivered NZ-Wide

Manufactured in Hamilton and supplied throughout Waikato and New Zealand.

Key Specifications

Size: 15-20mm

Material: Recycled crushed concrete

Performance: Strong drainage, high stability

Uses: Larger trenches, retaining walls, soak pits, backfill, pipe bedding

Order 15-20mm crushed concrete drainage metal today

Contact us today for pricing, availability, and delivery options across Hamilton, Waikato and the rest of NZ.