OBRAS ONSITE · free site calculator

Reo & Mesh Calculator

Mesh sheets for the slab with lap allowance, bar weight by size for ordering, and chairs so the reo actually sits where the engineer drew it.

Mesh for a slab

Slab length (m) Slab width (m) Mesh

Sheets are 6.0 × 2.4 m; effective coverage after 2-square laps ≈ 5.8 × 2.2 m (12.76 m²). Chairs at 800 mm centres. Always order to the engineer's drawings - this gets you the budget number.

Bar weight for ordering

Bar size Total length (m)

Weight = d²/162 kg per metre (standard deformed bar). Add your lap lengths to the total metres before you order.

Steel-fixing SWMS & ITP in the Concrete, Formwork & Structure pack · All free tools →

Want a person to look at it?

The tools above are free and yours to use. When you need the paperwork behind them reviewed by someone who has run sites, Obras HSE Services is a live consulting business in south-east Queensland.

SWMS review service — a marked-up review showing what is missing and why it matters.
Construction HSE health check — an independent look at what is in place and what carries exposure.
All Obras HSE Services — scoped and priced before anything starts.