Poroton or lime sand stone

Our concerns about the calcium silicate brick solution are not directed against the stone itself, but rather the necessity of the ETICS, which we actually do not want because of algae growth and durability (we have some examples in the neighborhood where the outlines of the panels can be seen)!

Is it really the case that with monolithic construction using Poroton, the risk of mold formation due to thermal bridges is increased? Or rather, that with ETICS the mold risk is significantly reduced because the thermal bridges are insulated?

If executed reasonably properly, you have no risk of mold with either variant... Besides [WDVS], there is also the possibility of a two-shell construction ([Klinker]).

Thank you for the assessment! Clinker is visually not desired and probably also too expensive. But then the thermal bridge issue is not an argument against the brick as such – even if subsequent "wrapping" may be easier from the planning side. Then the question arises why the architect resists the brick so much. After all, it is his task to plan it in such a way that thermal bridges are minimized...

Something like this is not always rational – you are simply convinced of something or not – or have had experiences or not. As already mentioned here, you have a separation of functions with KS and VDVS and a mixture with [Ziegel].

Cracks in the stone with KS? You can hardly break that. You would also see that inside, for example in the unfinished basement/garage...

No cracks in the stone, the cracks appear in the joints and at the transition to other materials, e.g. to the concrete ceiling. If the stone is not plastered or wallpapered after plastering, you simply do not see such things. But believe me... they are there...

The structure is totally secondary, the main thing is that the company carrying out the work is familiar with the system. If you live in the house and everything is properly executed, you will never notice a difference (ok, except when drilling...). Indoor climate is identical, exceptions prove the rule (for example, if you live on a main road and need a lot of sound insulation, KS is probably superior).

Personally, I am a fan of functional separation, meaning stone + ETICS, but that is simply a matter of taste and I would have been fine with anything as long as my main contractor has a lot of experience with the system...