Concrete Volume Calculator

Concrete Slab Guide

Correct Depth by Use

Garden path (pedestrian): 75–100mm. Patio (pedestrian): 100mm. Domestic driveway: 100–150mm with hardcore base. Garage floor: 150mm. Vehicle crossing: 150mm reinforced. Shed base: 100mm. Always lay on a compacted hardcore sub-base of 75–100mm.

Ready-Mix vs Bagged

For volumes over 0.5–1 m³, ready-mixed concrete is more economical and consistent. Minimum ready-mix orders are typically 1 m³. Under 1 m³, use bagged ready-mix concrete (25kg bags make approximately 0.012 m³). Hiring a cement mixer makes large bag mixes much easier.

Reinforcement

Domestic garden slabs don't typically need reinforcement. Driveways should use A142 mesh (steel fabric) for vehicle traffic. Any slab subject to differential settlement (tree roots, poor ground) benefits from mesh. Lay on polythene DPM and allow 28 days before loading.