ᐅ Concrete slab poured too large – it has now been cut down – is this acceptable?
Created on: 1 Oct 2020 09:22
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SporttascheS
Sporttasche1 Oct 2020 09:22Hello 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.
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.
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vorkalmatador1 Oct 2020 09:31A building surveyor would be worth their weight in gold right now.
In general, I would be very cautious. The site manager will of course say, "Yeah, it’s fine as it is," but what else could they say?
Definitely get a second opinion before proceeding any further.
In general, I would be very cautious. The site manager will of course say, "Yeah, it’s fine as it is," but what else could they say?
Definitely get a second opinion before proceeding any further.
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Osnabruecker1 Oct 2020 18:33The problem is no longer the foundation slab. As long as it is properly installed and the reinforcing steel has the correct concrete cover, everything is fine...
But if the strip footings are also positioned incorrectly, definitely consult a structural engineer.
(The width of the excavator bucket is nonsense... they come in all different sizes!)
But if the strip footings are also positioned incorrectly, definitely consult a structural engineer.
(The width of the excavator bucket is nonsense... they come in all different sizes!)
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Sporttasche1 Oct 2020 19:17Can the strip foundations really be off? After all, it’s only 16 cm (6 inches) that have been cut off in the end.
If the strip foundations are not positioned correctly, I would definitely recommend consulting an expert. I also believe the strip foundations are incorrect because when nailing the formwork, it should be noticeable if the slab is becoming too large, assuming the foundations are correct. Or am I wrong?
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knalltüte1 Oct 2020 20:47Do you mean the frost protection edge when you say strip footings? It’s something similar...
What exactly are you getting— a load-bearing slab about 25-30cm (10-12 inches) thick or strip footings plus a slab? In that case, the loads are transferred through the strip footings, and the slab is usually only up to about 16cm (6 inches) thick.
What exactly are you getting— a load-bearing slab about 25-30cm (10-12 inches) thick or strip footings plus a slab? In that case, the loads are transferred through the strip footings, and the slab is usually only up to about 16cm (6 inches) thick.
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