Which reinforcement mesh do I need?

A142 (6mm wires) for paths and light-use slabs. A193 (7mm) for driveways and domestic floors — this is the most common choice. A252 (8mm) for heavy-duty floors and raft foundation edges. A393 (10mm) for industrial floors and raft foundations. The letter A means square mesh (same spacing both directions, 200mm).

How much overlap for mesh sheets?

Mesh sheets must overlap by at least 2 squares — for standard 200mm spacing, that's 450mm (rounding up from 400mm to include a tie point). At every overlap, tie the sheets together with wire at 600mm centres. The overlap ensures continuity of reinforcement across sheet joints. Never butt sheets together without overlap.

What are spacer chairs for mesh?

Spacer chairs (bar chairs or stools) hold the mesh at the correct height within the concrete slab — typically at mid-depth for single-layer mesh, or at specific cover depths. Space chairs at 600mm centres in both directions. Without chairs, the mesh sinks to the bottom during pouring and provides no structural benefit.

How heavy is a sheet of mesh?

Standard sheet sizes are 4.8m x 2.4m. Weights per sheet: A142 = 25.6 kg, A193 = 34.8 kg, A252 = 45.5 kg, A393 = 71.1 kg. A193 sheets are manageable for two people. A393 sheets are heavy and may need mechanical lifting. Mesh can also be ordered in custom cut lengths.

Can I use fibre reinforcement instead of mesh?

Steel or polypropylene fibres can replace mesh in some applications (mainly crack control in non-structural slabs). However, for structural slabs, foundations and any application requiring a specific reinforcement area, mesh or rebar is essential. Fibres don't provide the same structural capacity as mesh. Always follow the structural engineer's specification.

TradeCalculator

Reinforcement Mesh Calculator — Sheets, Overlap & Chairs

Calculate reinforcement mesh sheets by slab use, with 450mm overlap, spacer chairs and tie wire.

Slab Length

Slab Width

Mesh Type

7mm wires, 3.02 kg/m2

Mesh Sheet Price

Chair Price

How We Calculate This

This calculator determines the number of mesh sheets needed for a concrete slab, accounting for overlaps, plus spacer chairs and tie wire.

Sheet count

Sheets Long = ceil(Slab Length / (Sheet Length - Overlap))
Sheets Wide = ceil(Slab Width / (Sheet Width - Overlap))
Total Sheets = Sheets Long x Sheets Wide
Standard sheet: 4.8m x 2.4m, overlap: 450mm (2 squares).

Accessories

Chairs at 600mm centres in both directions. Tie wire at each overlap intersection (approximately 300mm per tie, 4 ties per overlap).

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.