Shuttering blocks: block quantity and fill concrete
Shuttering blocks (formwork blocks) are filled with reinforced concrete: the fill concrete is the quantity people most often get wrong. For a 20 cm block, allow about 115 litres of concrete per m² of wall. The calculator does the full count: blocks, concrete, and the ready-mix truck equivalent.
| 📐 Wall area | |
| ▦ Shuttering blocks (50 × 20, incl. breakage) | |
| 🏗️ Fill concrete | |
| 🚛 Mixer truck equivalent |
A shuttering block wall is a reinforced concrete structure: vertical and horizontal bars at every course depending on the loads (earth pressure, swimming pool), tie beams and a design study if the wall retains soil. Fill in lifts of about 1.50 m, never in a single pour over the full height.
Fill reference
| Block thickness | Concrete per m² of wall | Per 10 m² |
|---|---|---|
| 15 cm | ≈ 90 L | ≈ 0,9 m³ |
| 20 cm | ≈ 115 L | ≈ 1,15 m³ |
| 25 cm | ≈ 150 L | ≈ 1,5 m³ |
| 30 cm | ≈ 190 L | ≈ 1,9 m³ |
The blocks almost always have a 50 × 20 cm face: 10 blocks per m², just like a standard block — but the hidden cost is the concrete inside, which this calculator gives you to the nearest litre.