How Much Reinforcement Mesh Do I Need?
Quick Answer
Slab area ÷ effective sheet area (allowing for overlaps)
Based on: standard sheet size 4.8m × 2.4m = 11.52m². With 200mm overlaps, effective coverage ~10m² per sheet.
How We Calculated This
Example — 4m × 3m slab (12m²):
- Sheet size: 4.8m × 2.4m = 11.52m²
- Effective area per sheet (with 200mm overlaps): ~10m²
- Sheets needed: 12 ÷ 10 = 1.2, round up to 2 sheets
Common Mesh Types
- A142: 6mm bars at 200mm centres. Light domestic — paths, shed bases
- A193: 7mm bars at 200mm centres. Standard domestic — driveways, garage floors
- A252: 8mm bars at 200mm centres. Heavy duty — structural slabs
- A393: 10mm bars at 200mm centres. Commercial/industrial
Key Rules
- Overlap: Minimum 200mm (one full square) at all joins
- Cover: Position the mesh at the bottom third of the slab on spacers (typically 40mm cover)
- Tie wire: Tie overlapping sheets together with binding wire
- Edge clearance: Keep mesh at least 50mm from slab edges
Do I Always Need Mesh?
Not all slabs require mesh reinforcement. For a simple garden path or shed base on good ground, an unreinforced slab may be adequate. However, mesh is strongly recommended for driveways, garage floors, and any slab that spans soft spots or is subject to heavy loads.
Last updated: April 2026. For structural slabs, always follow a structural engineer’s specification for mesh type and positioning.