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.
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.
KingJulien8 Oct 2020 14:31FloHB123 schrieb:
If scratches on the paint of a new car are professionally repaired before delivery (if necessary by replacing the affected parts), you definitely won’t get a discount; instead, they will simply not mention that there was a defect. It still counts as a new car without defects.
So I don’t see any reason to withhold payment here. The comparison is seriously flawed.
Nevertheless, I wouldn’t expect any discount here or waste energy demanding one.
Better to be cooperative and let your builder know that from now on you don’t expect such major mistakes anymore.
And of course, keep the email well saved
(I hope that is legally sufficient as protection).
Hello
In my opinion, cutting off the concrete slab was a foolish decision. It would have made more sense to build the house on the oversized slab.
The concrete, including the reinforcement, was cut off. Then bitumen or a similar material was applied on top. The structural engineer says the structural integrity is fine. That may be so. But the reinforcement has no proper concrete cover. If something goes wrong, the bitumen could have a small damage somewhere. After 15 or 20 years, rust will have done its damage, the reinforcement will have corroded inward, and the house will settle. After 25 years, cracks from settling may appear. That worries me. The structural engineer is not responsible for the correct installation of the reinforcement. He only said: it’s fine now.
Cutting it off was completely insane.
Steven
In my opinion, cutting off the concrete slab was a foolish decision. It would have made more sense to build the house on the oversized slab.
The concrete, including the reinforcement, was cut off. Then bitumen or a similar material was applied on top. The structural engineer says the structural integrity is fine. That may be so. But the reinforcement has no proper concrete cover. If something goes wrong, the bitumen could have a small damage somewhere. After 15 or 20 years, rust will have done its damage, the reinforcement will have corroded inward, and the house will settle. After 25 years, cracks from settling may appear. That worries me. The structural engineer is not responsible for the correct installation of the reinforcement. He only said: it’s fine now.
Cutting it off was completely insane.
Steven
S
Sporttasche8 Oct 2020 16:03Steven schrieb:
Hello
In my opinion, cutting off the concrete slab was a foolish decision. It would have made more sense to build the house on the oversized slab.
The concrete, including the reinforcement, was cut off. Then bitumen or something similar was applied on top. The structural engineer says the structural integrity is fine. That may be true. But the reinforcement has no proper concrete cover. If something goes wrong, the bitumen might have a small defect somewhere. After 15 or 20 years, corrosion will have done its damage, the reinforcement will have corroded inward, and the house will settle. After 25 years, some settlement cracks might appear. That would worry me. The structural engineer is not responsible for the correct placement of the reinforcement. He only said: “It’s fine now.”
Cutting it off. Completely crazy.
StevenYour statement gives me a headache! :-(
We had a case that was similar but much smaller in scale. During the formwork for the basement, the contractors were a bit careless, causing the formwork panels on one wall to shift while pouring the concrete. As a result, the wall became about 3 cm (1.2 inches) thicker and uneven over a length of approximately 2 meters (6.5 feet). There was also a step in the otherwise straight wall since only one formwork panel was affected. We considered chipping out the affected area, but our architect (really ours) and the contractors strongly advised against it due to the concrete cover over the reinforcement. The solution was to plaster the room slightly thicker at the contractor's expense. Although this reduced the living space by 0.12 m² (1.3 sq ft), the interior plasterwork was free, and it eliminated any long-term concerns.
Sporttasche schrieb:
Your statement is giving me a headache! :-(Hello SporttascheI'm sorry. That is just my (non-expert) opinion.
After building three houses, you tend to be more realistic.
Cutting off, including the structural engineer’s approval, shouldn’t be a big issue. I personally wouldn’t have shortened it.
Steven
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