36.5 cm aerated concrete and KS cladding? Ventilation behind or bonding?

Partially, only on one side of the house, "adjacent" plaster, originally not conceived as part of the wall construction: that clearly smells like facing bricks - which, by the way, are simply full clinker bricks cut into slices. Just out of curiosity still asked: what did you mean at the beginning by "lathing" - and by "calcium silicate brick facing"?

Also the info from the friend; he solved it like this at his place: 24 cm aerated concrete, structural timber with mineral wool, vapor-permeable membrane, counter battens, fiber cement boards and then covered with clinker bricks. I have no idea about that. He definitely has extremely good U-values. In summer the house is cool, in winter warm. Hardly any heating costs.

But for us it’s about the street side..

You are mixing everything up. So 36.5 Ytong is enough insulation. On that, plaster without Styrofoam and such stuff is sufficient. Alternative to plaster then is cladding. Nothing more is needed.

You are mixing everything up. So 36.5 Ytong is enough thermal insulation. On that, plaster without Styrofoam and such stuff is enough. Alternative to plaster would be facing bricks. Nothing more is needed.

I am aware of that. 11ant had asked about the original intention, and I had only explained the wall structure of the friend, which he installed at his place. We are satisfied with the 36.5 one. And also with proper klinker facing bricks.

The wall structure of the friend is too complicated for me.

Oh, Kalksandstein klinker should have meant Kalksandstein klinker.

Oh, Kalksandstein Klinker should be called Kalksandstein Klinker.

Exactly, that sparked my doubt: I wouldn't call Kalksandstein exposed masonry / facing bricks klinker; I associate klinker only with stones of the brick family, and I don't recall ever encountering Kalksandstein as thin bricks. They may exist, but at least they are significantly less common on the market. I also can't imagine an appealing / "worthwhile" contrast to a plastered surface there.

Yes, yes. Common in the north. There are various ones from Emsländer, from Silka herself, etc....