How is this calculated?

Using standard material quantities and coverage rates for UK garden projects.

Should I add extra for wastage?

Yes, 5-10% extra is recommended for cuts and spillage.

Where can I buy materials?

Most garden centres, builders merchants, and online suppliers stock these materials.

What is polymeric jointing sand?

Polymeric sand contains a binding agent that hardens when wet, locking pavers in place and preventing weed growth. It is more expensive than kiln-dried sand but much more durable.

How do I apply jointing sand?

Sweep kiln-dried sand into joints with a soft broom, working diagonally across the paving. Repeat until joints are full. For polymeric sand, follow the product instructions and activate with water.

GardenCalcs

Jointing Sand Calculator

Calculate kiln-dried or polymeric jointing sand for paving joints.

Paved Area

Total paved area including all joints

Joint Width

Width of gaps between paving slabs (typically 2-10mm)

Joint Depth

Depth of joint to fill — typically 20-30mm for paving slabs

Sand TypeKiln-dried is cheapest; polymeric resists weeds and washout

How We Calculate This

This calculator estimates jointing sand based on the paved area, joint width, joint depth and sand type.

Coverage rate

kg/m² = (jointWidth / slabPitch) × jointDepth × sandDensity. Wider joints and deeper joints need more sand. Polymeric sand is denser than kiln-dried.

Sand types

Kiln-dried: Fine, dry sand swept into joints. Cheapest option but can wash out.
Polymeric: Hardens when wetted. Prevents weed growth. More expensive but long-lasting.
Silver sand: Very fine grade. Good for narrow joints under 3mm.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.