How Much Pebble Do I Need Per m²?

Estimating Pebble Requirements

For most permeable resin-bound surfaces, the rule of thumb is one 25 kg bag of washed pebbles for each square metre. This guideline is based on achieving the optimal thickness and compaction for durable outdoor floors. Upgrading a 70 m² terrace would typically require around 70 bags, though the actual quantity may vary based on your chosen layer thickness and the size of the stone aggregate.

• Standard application: 1 bag (25 kg) per m²
• Thicker layers or larger stones may increase the quantity needed
• Always round up to allow for edge trims and potential wastage

Buying and Installation Tips

It’s best to select pre-washed, ready-to-use pebbles to ensure reliable drainage and minimal surface runoff. When buying, check for consistent sizing (typically 4-8 mm) for even mixing and laying. If you want a convenient solution, consider a combined kit such as Flowstone – Complete Permeable Floor Kit, which includes pebbles and resin.

• Order a few extra bags to cover accidental spillage or last-minute increases in coverage area
• Store bags in a dry area until use to prevent moisture issues
• Follow guidance on resin selection for white or coloured stones

When Should You Recalculate?

Adjust your calculation if you’re planning decorative features or varied thicknesses across the terrace. Mosaics, steps, or high-traffic areas may call for extra stone. It’s also advisable to review installation instructions, as some resin binders recommend specific ratios or mixing practices for best performance.