Base plate with concrete core activation. What is your opinion?

If the risk or the costs resulting from it were assessed as high, the topic would probably have been rejected in commercial construction already.

I hadn’t seen it that way before. Good point.

According to statements, the Swedish slab also does not need impact sound insulation, as no or hardly any impact sound is generated due to the mass of the concrete. That also sounds understandable, and the slabs have been around for a few years now, and if there were a problem here, it would be more well-known or something would have been done about it, right?

If I build conventionally, I would have the same insulation values and might even come out a bit more expensive in terms of costs. The disadvantage would then be the moisture and the longer drying time of the screed. Would there be any other advantages or disadvantages?

A Schwedenplatte basically only works with a timber frame house. Since that is not the case here, the matter is settled anyway.

I had also looked into that and discussed it with the architect. He thinks they are too expensive and the slab manufacturer wants to install his underfloor heating, which the heating installer does not want. At the latest in the upper floor, the question arises as to who will do it and it may result in mixed systems (although I think that can certainly be resolved ). Otherwise, the insulation of the slab is nothing special. You save the formwork by using continuous XPS insulation. You can also make that yourself if you consider it a good system. There are also "kits" for it, e.g. Jackudur Atlas, if I remember correctly. Ultimately, to meet the Energy Saving Ordinance or a KFW standard, you need insulation with a target U-value specified by the energy consultant (or whoever did the calculations). Let's say in total 20 cm of insulation must go "below". Then you can consider whether to put it under the slab, above, or both. Problem with "underneath": XPS is significantly more expensive than EPS. We ourselves plan, in consultation with the engineers, to use as thin XPS as possible and the rest as EPS under the screed.

As stone, we plan to use a sand-lime brick with an ETICS made of Multipor (cost issue)

Multipor for cost reasons? Then good luck with the tender
If you want it cheap, take EPS. Mineral wool already costs significantly more (boards more expensive, doweling necessary). Multipor comes after that and has the disadvantage of a worse insulation value (EPS/neopor have WLG 035 or 032, mineral wool likewise, Multipor 045), resulting in a thicker wall construction.

Regarding heat storage mass, thanks to sand-lime bricks in the house you already have more than enough, so in my opinion that is not an argument.

A Schwedenplatte basically only works with a timber frame house. Since that is not the case here, the topic is settled anyway.

It reads quite differently from the manufacturer.
Where does this statement come from?

The purpose of the slab is to be able to do without an additional floor structure and to already incorporate everything that would otherwise be placed on top into the slab.
The requirements for tolerances in the screed are significantly higher than those for a floor slab, but they would then also have to apply to the floor slab.
You can only manufacture it once the increased requirements are contractually established.
However, if you place a solid house on such a floor slab, preferably with 2 reinforced concrete ceilings, the "little sheet" will deform so much that you will need to apply a screed again to have a flat floor. This will not happen with a timber frame house. Without knowing the background, the Sweden board will probably come from Sweden, where this is the standard way of building.

I also looked into it and discussed it with the architect. He says they are too expensive and the slab manufacturer wants to install their underfloor heating, which the heating engineer does not want. By the latest in the upper floor, the question arises who will do it and may lead to mixed systems (although I think that can certainly be solved ).

I don’t have any concrete offers right now, but according to my research, the cost difference between conventional and thermally activated concrete slab is not very big. For the upper floor, a conventional construction method is planned.

Otherwise, the insulation of the slab is nothing special. You save the formwork through the continuous XPS insulation. You can also make that yourself if you consider it a good system. There are also "kits" for it, e.g. Jackudur Atlas, if I remember correctly. Ultimately, to meet the Energy Saving Ordinance or a KFW standard, you need insulation with a target U-value specified by the energy consultant (or whoever did the calculation). Let’s say that overall 20 cm of insulation must go "downwards". Then you can consider whether to put it under the slab, above it, or both. Problem with "underneath": XPS is significantly more expensive than EPS. We ourselves plan, in consultation with the engineers, to use as thin XPS as possible and the rest as EPS under the screed.

We are not completely fixed on the Swedish slab or similar and are open to alternatives. I quickly looked and either XPS is twice, or even five times as expensive as EPS. But... the price for XPS (500kPa) is about €7.60/m² [1]. EPS was around €1.60/m², and for a slab of 120m² that makes a difference of €200 to €1,000. Of course, that is many times more, but given the total cost of a house, I still find it within reason. The price difference in bricks is much more significant. Or am I calculating wrongly?

We ourselves plan, in consultation with the engineers, to use as thin XPS as possible and the rest as EPS under the screed.

What exactly is your build-up and what costs per m² do you calculate? The Swedish slab has a similar system[2]

The point of the slab is to be able to do without an additional floor buildup and already integrate everything that otherwise has to go on top into the slab. The requirements for tolerances in the screed are much higher than those for a slab but would then also have to apply to the slab. You can only make it if you contractually define the higher requirements. But if you put a solid house on such a slab, ideally with 2 reinforced concrete ceilings, the "sheet" will deform so much that you will have to install a screed again to have a flat floor. That won’t happen with a timber frame house. Without knowing the background, the Swedish slab probably comes from Sweden, where this is the standard way to build.

No, the Swedish slab is a German company from Berlin that builds a slab according to the Swedish principle. However, it is not exactly the same. Futura, in my opinion, builds a similar slab and simply calls it Futura. I am reading your objection for the first time now. According to the manufacturer’s website, the slab is suitable for all types of houses and I have also read several times that solid houses have been built on a Swedish slab without problems. Do you have sources for your claim, or is it an assumption of yours?