ᐅ Bending-resistant slab foundation driven over by a truck in less than one day

Hello,

we are just starting to build our own home on the neighboring lot from a local developer. Unfortunately, the beginning has been far from pleasant. But let me explain step by step:

We are handling the groundwork ourselves through a contractor. The start date was April 29.
Our assigned site manager already pressured us about 4 weeks ago because another construction project had fallen through or something similar. He wanted to proceed quickly with the foundation slab. Since the groundwork contractor was repeatedly pulled away due to other tasks, the planned date for the foundation slab didn’t happen.
Now, once the groundwork was properly underway, the site manager started pushing again on May 6 because someone else had dropped out. He wanted to do the detailed surveying on May 10 and pour the foundation slab on May 13. Unfortunately, our groundwork contractor said that despite some difficulties, they could still manage if the slab got in their way. Apparently, this was taken by our site manager as a green light.
After two days of reflection and discussing with the groundwork contractor, I told him that we would prefer to complete the groundwork before the foundation slab is poured. Since we are also planning a carport with a tool shed, I wanted the surveyor to mark everything at once and also begin the masonry work on the garden hut ourselves. I brought this up several times with the site manager, explaining that we were not yet ready for the detailed surveying or the foundation slab. Everything was consistently dismissed with claims that it would all be fine. The evening before the detailed survey, I called the surveying office myself and canceled the appointment for May 10 because the site manager showed zero responsiveness.

On the morning of May 10, I got a call from the site manager saying that I couldn’t do that because he had already scheduled the workers and ordered everything two weeks earlier (why didn’t he tell me this two weeks ago? Very strange...). He rescheduled the surveying company for the detailed survey, which they unfortunately did. So I sent an email to the developer that morning saying that I was not okay with this and found the way they were treating their customers outrageous. To this day, no response. Consequently, the foundation slab was poured on May 13 as planned by the site manager and against my wishes. I was furious.
Additionally, our construction execution drawings were not finished yet; we only received them by mail on May 11. On Sunday, May 12, we relocated the washing machine, which involved rerouting a drain. We informed the developer the same day and requested immediate feedback. Nothing was signed off yet (and still isn’t). A call to the developer on Monday morning shocked me even more. They said the drain relocation was no longer possible. If I hadn’t personally instructed the workers on site (luckily I was working from home), we would now have an incorrect drain in the foundation slab. I couldn’t believe it.

Now to my question...

The foundation slab (reinforced, because the ground is not stable) was poured on the 13th around 2 p.m. and covered around 3 p.m. The following day, late morning (around noon), the bricks were already delivered. Since my parents live next door, they were able to observe and take photos. Around midday, I received a picture showing the truck with bricks driving onto the foundation slab, lowering its support legs to unload the bricks behind the “house.” Our groundwork contractor just shook his head and asked why they were driving on the foundation slab. “We always do it this way,” was the answer. I was horrified that the drivers dared to bring a 20-ton truck onto a slab less than a day old. Is this normal? Apart from the fact that the Ytong blocks were placed on the slab, although those areas are relatively light in weight compared to others.
In the evening, after work, I checked the site myself. The formwork for the foundation slab was slightly indented and cracked, and some of the slab surface had chipped (the masons have since patched and covered the damage. There are photos available if anyone wants to see them).

Is it allowed for foundation slabs to be driven on so quickly with such heavy equipment? Our construction expert tried to reassure me but said there was nothing they could do, and my photos wouldn’t help.

I feel like I’ve aged ten years in the last few days. I’m completely speechless about how a client is treated right from the start of construction.

Maybe someone can offer some advice. I’m really desperate right now.

Well, it’s quite unfortunate.
When concrete reaches sufficient strength depends on many factors.
“Standard” concrete with “regular” cement needs about 2-5 days to achieve a defined initial strength at the currently very cold temperatures.
If the truck put too much stress on the concrete, you can check it with a straight edge.

Thanks for the tip, but what is a leveling rod and what is it used to measure? Can it be done alone? Meanwhile, the walls of the ground floor are already standing.

The only ones who say that the concrete can handle this are the people from the developer. Everyone else just shakes their heads. It is supposedly fast-setting. Hard after 6 hours, driveable after 10 hours.

It could be possible, as the neighbor who built with a well-known basement company also had their basement installed within 48 hours. What I don’t understand, however, is that your parents saw this and didn’t say anything. PS: Are you sure it’s a developer? Legally, you have no say until the handover.

Yes, we are building with a company that is constructing the house for us. And am I only allowed to report defects in the foundation slab upon handover? Would the house then have to be demolished?

And my parents have no authority to do anything there. What were they supposed to say?
Apart from the fact that "would have, could have, should have" unfortunately doesn’t help me... but 48 hours is a completely different matter than 20–22 hours.

Based purely on experience from several construction sites, it is quite common to distribute the pallets of bricks on the foundation slab the following day. After all, there is still a fine grading layer under the concrete and beneath that a gravel layer.
However, driving a truck on it is something I haven’t heard of before, that’s new to me. I don’t understand why a driver would take the risk of damaging the vehicle (a foundation slab is comparable to a 20cm (8 inch) curb) and then place the bricks behind that, where they have to be dragged forward again.

It’s an unfortunate situation, and there’s probably not much you can do about it. The suggestion to use a straightedge is nice, but it’s definitely not long enough. If anything, take height measurements with a laser, but to prove any changes, you would also need to know the previous heights. Concrete work is not done to the millimeter. A foundation slab can easily have height differences of up to 2cm (0.8 inch).