20-40mm Crushed Concrete Drainage Metal

Heavy-duty drainage metal ideal for civil works & large-scale water management

Our 20-40mm crushed concrete drainage metal is a robust, larger-grade recycled aggregate designed for high-volume drainage applications and civil infrastructure projects. With particle sizes between 20mm and 40mm, this metal offers exceptional flow characteristics and structural bulk.

It’s widely used for large trenches, soak pits, drainage blankets, and applications where superior water movement and stability are essential.

Typical Applications

  • Stormwater trenches & high-flow drainage systems
  • Soak pits & attenuation systems
  • Drainage layers beneath roads & foundations
  • Civil infrastructure backfill
  • Retaining wall drainage zones (medium to large scale)
  • Rural drainage channels & farm infrastructure
  • Rail & service trench drainage


The 20-40mm size is especially valued for applications requiring rapid water movement and reduced clogging risk.

Why Choose 20-40mm Recycled Crushed Concrete?

✔ Superior Free-Draining Performance

The coarse aggregate size keeps channels open for reliable, high-volume water movement.

✔ Ideal for High-Load & Deep Trenching

Increased particle size and mass support stability in heavy civil environments.

✔ Highly Sustainable Material Choice

Recycling concrete significantly reduces environmental impact and supports NZ’s circular construction economy.

✔ Durable Angular Profile

Helps resist settlement while improving structural reliability.

✔ Local Supply from Hamilton

We deliver across Waikato and NZ-wide.

Key Specifications

Size: 20-40mm

Material: Recycled crushed concrete

Best for: Large trenches, stormwater, road foundations, civil drainage

Benefits: Strong flow, low clogging, high stability

Need 20-40 mm drainage metal?

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