20mm Scoria

The colour typically ranges from deep red-brown and maroon through to dark rust and charcoal, giving it a distinctive volcanic look that is visually appealing in open landscaping. The combination of lightweight, porosity, and angular interlock makes 20mm Scoria a versatile choice across drainage, backfill, filtration, and erosion control projects.

Key characteristics:

• Approx. 20mm lightweight volcanic rock aggregate
• Highly porous and vesicular for superior water flow
• Distinct red-brown and charcoal volcanic colour palette
• Suitable for drainage, landscaping, and construction applications

Usage

20mm Scoria is widely used by civil contractors, landscapers, builders, and councils where a free-draining, lightweight aggregate is required:

1. Drainage & Backfilling

   • Ideal for backfilling around retaining walls, pits, tanks, and structures where drainage and reduced load are important.
   • The porous, angular stones create a high-void, free-draining zone, reducing hydrostatic pressure and aiding water movement.

2. Filtration Systems

   • Commonly used in bio-filtration, rain gardens, and other water-sensitive urban design (WSUD) systems.
   • Its natural porosity allows for enhanced water flow and storage, supporting filtration media above or around it.

3. Erosion Control

   • Suitable for stabilising slopes, swales, and exposed surfaces, helping slow water, reduce erosion, and protect underlying soils.
   • The angular particles interlock well, resisting washout in many surface applications.

4. Landscaping & Decorative Use

   • Popular as a decorative mulch or feature rock in garden beds, around trees, and in rock gardens.
   • The bold volcanic colours provide contrast against plants, pavers, and concrete.

5. Lightweight Fill (Non-Structural)

   • Used where reduced dead load is beneficial, such as over certain structures or in raised landscape features (always subject to engineering advice).

Application Tips:

• For drainage and filtration, consider lining excavation with geotextile fabric before placing scoria to reduce soil intrusion.
• When used decoratively, rake level after placement and top up over time as needed.
• Always consult a qualified engineer before using 20mm Scoria in any application with structural or design performance requirements.