Measures · Clay block and concrete slab
Clay block and concrete slab pre-sizing FREE
Work out the thickness of a clay block and concrete (hollow-block) slab from its span. Below the result you find the formula and the standard.
Indicative pre-sizing. It does not replace a structural calculation signed by a licensed engineer. For seismic zones with agS (design ground acceleration) > 0.15g, long spans or use classes III/IV → talk to a structural engineer.
Pick a calculation from the list to start.
Formula, example and standard
H ≥ max(L/25, 16 cm) · topping ≥ 4 cm
Example with the starting values (Span L: 4.5 m): Thickness H ≥ 18 cm. Joist spacing < 15 · topping thickness (≈ 60 cm for a 4 cm topping).
- The L/25 rule works for standard residential; go to L/20 for roofs.
- Concrete topping at least 4 cm, reinforced with welded mesh.
- Hollow or solid clay blocks (pignatte) depending on load and the insulation you need.
Source: NTC 2018 §7.2.6 · biblus.acca.it
Indicative pre-sizing: it does not replace a calculation signed by a licensed engineer.
The other calculations
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