ᐅ Concrete slab poured too large – it has now been cut down – is this acceptable?

Created on: 1 Oct 2020 09:22
S
Sporttasche
Hello dear experts,

We are just at the beginning of our build, and already the first issue has occurred. The concrete slab was poured too large! It’s actually surprising how something like this can happen, but it did (by the way, the slab was done by a very well-known company).

The slab is 16 cm (6.3 inches) too long on one side, and this also affects a recess for the bay window.

This was noticed during the slab inspection. We were told that it can happen (which was visibly embarrassing for the site manager) and that they would fix it. Yesterday, the slab was "cut back" by the mentioned 16 cm (6.3 inches). They used a type of cutting disc similar to those used in road construction to grind the slab. Since the slab is much thicker than the cutting depth of the disc, the rest was painstakingly removed with a pneumatic hammer. The area was then re-plastered.

Well, apparently everything is fine now, which I really hope is true. I am not an expert, so I would like to hear the opinions of professionals here.

In my view, it can’t be as good as if it had been poured correctly. Here, a component was opened up and patched. The frost protection edge (frost skirt) that was originally 50 cm (20 inches) is now only 34 cm (13 inches) high (they say a maximum of 20 cm (8 inches) is needed and that it’s always 50 cm (20 inches) because the excavator’s bucket makes 50 cm (20 inches) wide trenches).

I’m already upset that the build started like this and I really hope we won’t have problems because of it down the line.

Which expert can give me some advice on this topic? Thank you!

P.S. By the way, it’s a KFW40+ house with a matching slab.
I
icandoit
17 Oct 2020 17:20
Quote from Baustatik Media Wiki: "Cracks develop in concrete elements when the tensile strength of the concrete is exceeded due to a load or restraint stress, or a combination of both. The width of these cracks must be limited in order to maintain the serviceability and durability of the element. Serviceability requirements include the appearance, watertightness, and functionality of an element, while durability focuses particularly on the corrosion protection of the reinforcement. In addition to limiting crack width, sufficient concrete cover is far more important to meet the requirements for durability and serviceability."

A house constructed using a timber frame method is comparatively lightweight compared to a brick or concrete structure.