ᐅ Minimum Thickness of the Concrete Slab and Blinding Layer

Hello forum members,

Is there a minimum thickness for the ground slab of a 1.5-story single-family house without a basement, and what exactly does the "cleaning layer" mean? Is it always necessary?

In our case, 16cm (6.3 inches) was planned. Is that too thin?

Unfortunately, I can't tell you if 16 cm (6.3 inches) is too thin.
Our foundation slab is 25 cm (9.8 inches) thick.

Sadir schrieb:

What does the term "cleaning layer" mean, and is it always necessary?

**A cleaning layer (also called blinding concrete) is a layer of concrete poured on the bottom of the excavation to create a flat, dry, and clean working surface. Typically, a cleaning layer is 5–10 cm (2–4 inches) thick and made from plain concrete of low strength class (e.g., C8/10).

The now withdrawn DIN 1045-3 standard required a cleaning layer before installing foundation slabs and footings to ensure the necessary precision when placing reinforcement spacers and thus guarantee the required concrete cover. The current European standard DIN EN 13670 does not require a cleaning layer, which means there is currently no normative basis for its construction. Therefore, the planner (usually the architect, in coordination with the structural engineer) must decide how to ensure a flat and clean base that meets the required cover dimensions during concreting.

**Source: BauWissenOnline

Sadir schrieb:

In our project, 16 cm (6 inches) was planned. Is that too thin?

Those are typical signs of a low-cost provider; yes – it’s rather minimal. How much too little it actually is will be determined by the structural calculations, assuming you have chosen this provider.

Regards, Bauexperte

Doesn’t it also depend on how much rebar was placed in the foundation slab? Ours is, I believe, 22cm (9 inches) thick, but I’ve also seen slabs up to almost 30cm (12 inches). The structural engineer should know how much is necessary, which likely also depends on the layout and external dimensions of the house...