How Much Resin and Stones for a 1.2m² Area at 20–40mm Depth?

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When planning a DIY permeable surface, one of the most common questions is how much resin binder and stone are required for a given area and thickness. Here’s a detailed guide to help you estimate for a 1.2m² space at a typical 20–40mm depth.

Calculating the Quantities Needed

For a 1.2m² area at a 20mm depth, you will generally need approximately 360kg of clean, dry stones and 10–11kg of high-quality resin binder. This approximation is based on the guideline that 432kg of stones and about 13kg of resin binder cover 1.44m² at 20mm thickness. For thicker layers up to 40mm, increase your quantities proportionally for proper coverage and structural stability.

Choosing the Right Products

For light-coloured or white stones, a non-yellowing polyurethane resin like Polirock is recommended. If you want something ready-to-go, a complete solution such as the Flowstone Complete Permeable Floor Kit includes all the required materials matched to your area. Make sure the aggregates are suitably washed, ideally using specialist products designed for permeable floors.

Tips for Effective Application

Prepare a stable and level sub-base before mixing and laying your stones and resin.
Thoroughly mix the resin with the stones to ensure even distribution and binding.
Work in manageable batches, especially for DIY installations, to maintain an even surface and finish before the resin starts to cure.

When Does Precise Measurement Matter?

Getting your calculations right is especially important for driveways and paths subject to regular foot or vehicle traffic. Underestimating materials can lead to weak spots and surface inconsistencies, while overestimating helps guarantee a more uniform, durable finish.

Related guides

Is Diy Permeable Flooring Durable

Calculating the correct amount of resin and stones is crucial for a smooth and long-lasting permeable floor. For more advice on planning and ensuring durability in DIY resin-bound surfaces, visit the Is DIY permeable flooring durable? hub for further guidance.