Reinforcement / Armature visible

Details that need to be clarified. However, I lack the necessary expertise for that. On Wednesday, there is a meeting with the site manager at the construction site.

Afterwards, I need to see what the expert says.

But thank you very much for the key points, I will address them on Wednesday and wait for the reaction.

Thermal bridges are not that... we are talking about the strip foundation. The underside of the floor slab does not consider that yet. I am also an absolute layman, but the solution sounds confusing to me. The load transfer takes place downwards, not sideways. I also don't believe that the joints can be sealed that easily. But hopefully the expert will know that.

I am not an expert either, but this exact problem has already been discussed several times in the green section.
If the foundation stands above the wall and is filled with soil, it creates a thermal bridge.

However, I think a few people with more expertise will still chime in.

I do not know the exact construction condition now, but to me it looks like this is a double-layer wall. Therefore, I think that a separate foundation was made for the cladding, which now shows this weakening. That would make sense as it would represent a decoupling of the thermal insulation from the wall and floor slab of the house.

If my assumption is correct, then underpinning and pre-concreting would indeed work. We did something similar during the renovation of a very old house that had a 50cm sandstone wall. We excavated about 2 meters and underpinned it with concrete and steel. At that time, surveyors, monument conservators, and structural engineers were involved and all approved it as okay. Meaning if it worked for us, why not here. The prerequisite is, of course, that it really is only the foundation of the outer leaf and not the actual floor slab.

But you could see that by the execution at the bottom.

This is another good example of why you should visit your construction site daily and take pictures with a digital camera until the doctor comes. It costs nothing and makes the analysis of such an incident much easier.

Regardless, a surveyor and possibly a structural engineer must absolutely come here and take a look.

Since we had a similar problem... albeit on a much smaller scale:

In general, it is possible to achieve the required concrete cover afterwards, for example with sprayed concrete. Why reinforcement should be added for this is less clear to me. I also do not understand why a thermal bridge should occur. It will be important that no water can accumulate on the concrete strip that might be "worked on."

Are there perhaps photos of the reinforcement of the base slab before pouring? Then it might be possible to see whether the necessary cover is at least given at the bottom.

It would be nice if you could present the result of your expert's assessment here for general information!

to me it looks like a double-layer wall. that's why I think a separate foundation was made for the brick cladding

Usually, a fairly wide frost protection strip is concreted. The slab is placed on that. The frost protection strip then typically protrudes about 30cm. The insulation and perimeter insulation as well as the brick cladding are placed on this "protrusion." They are certainly not separate foundations.