Wall thickness of expanded clay walls (Liapor) only 14 cm

Why half-knowledge? There was the EW 58 with subtypes or subvariants. EW 41, EW42, EW52, or EW 65 were then adapted variants. The house construction was also planned and organized in a command economy manner. There were new development areas just like today, and almost all houses resembled each other. Sometimes rotated, sometimes with a basement or garage and sometimes without, sometimes as a bungalow or duplex, etc.

So half-knowledge after all. I would not call the other mentioned models "adapted variants," only the concept was the same. Owner-built homes were not planned and organized in a command economy manner, everyone was left to their own devices to improvise the materials – with the EW homes, Genex was excluded, but no less against blue tiles ;-). The house models were planned at world level, therefore above Western standards, and the concept exemplary.

The construction of owner-occupied homes was not centrally planned and organized,.....

Of course it was. Not everyone could build. Material quotas were usually assigned. Supplies were mostly obtained through the BHG or in rural areas construction and material procurement were done by the ZBO.

There were practically no private construction companies. Either people built themselves within the framework of neighborhood help. Mostly, however, construction was done illegally. On weekends, after work. Without connections, so for a teacher or a doctor it was almost impossible to build. They had to buy something used.

You simply could not buy everything with money.

Then I recommend that you hopefully still in time read up here in the forum (or gladly also externally in my article "Ein Doppelhaus hat ZWEI Hälften") about the risks of uncoordinated construction of semi-detached houses without one's Hälftenpartner.

Thanks, but fortunately we are still on good terms and also sit together at the provider’s table. Sure, who knows what it will ultimately be. But even if each should choose a different provider, we still want to build in a coordinated way timewise and otherwise.

I am not a fan of experimental building materials and, on top of that, these thin-walled walls with a thicker layer of Styrofoam than the wall thickness itself. I would never build such a house.

There will always be problems when you want to make structural changes. Installing a kitchen, installing an awning or a patio roof, or simply attaching another lamp. Everything becomes difficult.

Exactly, that's why I also have an uneasy feeling. It is a modern concept that initially sounds plausible and has advantages (construction dries quickly, price, etc.), but I always think that you never know what the future holds and changes should be possible.

Clay aggregate is probably no longer experimental, yet asbestos was once a new material with great properties.

However, with brick-on-brick and KfW 55, there is almost always Styrofoam on the outside as well. And supposedly you can also use anchors in clay aggregate. But overall, I share your feeling!

Personally, I don't think much of ETICS except for the spacing,

So only monolithic? Is your house KfW55? I've been told the wall gets pretty thick then.

The boiler repairmen chisel into the walls as usual.

Boiler repairmen? :-) I didn't understand that.

However, with stone-on-stone and KfW 55, there is almost always Styrofoam in front as well.

Nonsense. Don’t just repeat what you’ve overheard somewhere. Take a look at the manufacturers’ brochures. With Ytong, KfW40 is easily possible monolithically. Also with filled Poroton bricks. And Liapor also has stones suitable for that. They are not much thicker either; your variant comes to 31cm, monolithic walls for KfW55 are usually 36.5cm. So about three finger-widths thicker.