We want to build, is what is being offered to us okay?

No no ^^ I have of course only mentioned excerpts that concern the insulation. We have a 12-page individual offer, based on a rather small-printed 7-page client service specification. Unfortunately, some points are really not described well enough, but I don't think I'll get more out of that for the individual contract because I would have to discuss every point individually and then also know where more details are necessary.

So the specification sheet from our architect for the insulation concerned the shell builder, the exterior plasterer, and the roofer and each covered only about 1.5 to 2 pages for the insulation layer. And that was ONLY the insulation layer with the corresponding conditions and details.

I think the construction expert is against it because they lack long-term experience (compression of the material).

To my knowledge, there are no experience values at all – neither short nor long term – because no builder who has insulated below the BP (slab) has had the surveyor come out again after 5 years to re-measure the ridge height. Only in this way, in my opinion, could it be definitively proven what real benefit sub-slab insulation brings.

In our latitudes, there is a frost line at 80 cm, which must be observed for all foundations to avoid frost heaving of the concrete. Therefore, under buildings, a layer of gravel is usually laid as frost protection. This directs rainwater away and prevents soil heaving during freezing. This also means that no significant cold can rise under a house built this way. It gets warmer downwards anyway, meaning at cellar level it hardly ever drops below 0 degrees; we do not live in Siberia.

But yes, basically I am in favor of insulation above the slab; I prefer to have it warm "in" the house and not underneath

Depending on the house, that can account for part of the heat loss.

On paper, with "assumed" values; as everyone knows, paper is patient

Rhenish greetings

Exterior walls are probably no longer going to be faced with bricks but plastered

Apart from the fact that this statement is simply wrong - what is the explanation for this statement?

I skimmed through a forum where they completely tore apart this exact wall construction (same developer)

I can understand that

Rhineland greetings

I can understand that
Rhenish greetings

Please say more about that, this is my basic question. What value does this exterior wall construction have? Is that a thinner stone? Does it have to be thicker? Is it thick enough? Does the thickness say nothing at all?

The stone must comply with the structural engineering - in my opinion, it is not too thin. It takes on the load-bearing function and in your case also provides a bit of insulation as well as sound and heat protection. The insulation is provided by the mineral wool. The [Klinker] is a bonus.