ᐅ Formwork for the foundation slab

Created on: 6 Oct 2025 21:44
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grunlilie
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grunlilie
6 Oct 2025 21:44
Hello everyone,

The wooden formwork for the basement slab has been installed. After the insulation was laid, the formwork on the inside is still about 20 cm (8 inches) high. According to the plan, the slab should be 28 cm (11 inches) thick.

Is it normal for the formwork to be lower like this? Will more be added on top? Should I address this with the construction company?

Thank you!
In der Ruine7 Oct 2025 06:28
Excuse me? I have read it three times now and still don’t know where you took the measurements.
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Teimo1988
7 Oct 2025 07:29
If I were you, I would be concerned as well. Sure, the insulation is compressed a bit at the bottom, but not by 8 cm (3 inches)...
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grunlilie
7 Oct 2025 08:29
In der Ruine schrieb:

Excuse me? I’ve read it three times now and still don’t understand where exactly you took those measurements.

As it stands, there would still be space for a 20cm (8 inches) thick slab, but according to the plan, we need a 28cm (11 inches) thick slab. Now I’m wondering if some kind of adjustment will happen or if we’ll need an expert report and end up having to remove the 20cm (8 inches) slab...
Nida35a7 Oct 2025 09:00
Check the planning documents again to see if it specifies 28cm (11 inches) of concrete alone, or if the total assembly of concrete, insulation, and waterproofing adds up to 28cm (11 inches).
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nordanney
7 Oct 2025 09:28
grunlilie schrieb:

Should I bring this up with the construction company?
It doesn’t hurt to ask. The answer might be something like 20cm (8 inches) of concrete, 8cm (3 inches) of insulation.
28cm (11 inches) of concrete would be quite a lot. 😉