Solid house: Which stone? Poroton, Liapor / expanded clay, Ytong?

Thanks for the comment - it pushed us back towards calcium silicate bricks... we will make a final decision once the energy saving ordinance calculation comes in or depending on what type of heating system it will be (with an air-water heat pump rather towards aerated concrete, with a ground-water heat pump towards calcium silicate bricks)
An alternative to ETICS is by the way clinker bricks with wool No problems with woodpeckers (and if so, the woodpecker deserves it)

I would prefer the red Poroton purely from an ecological perspective. In my view, it is still a stone that comes from nature and unlike the other competitors, it is not all chemistry.

An alternative to ETICS is by the way clinker with wool No problems with woodpeckers (and if there are, the woodpecker deserves it)

If there is money... But maybe the woodpecker deserves it after all
I also don’t know how far you get thermally with that at all. Because if you take an insulated stone on the outside or inside, then the building physics basis is at least partially unnecessary.

I would prefer the red Poroton purely from an ecological point of view. From my perspective, that is still a stone that comes from nature and is not, like the other contenders, all chemistry.

And what is supposed to be so ecological about Poroton? Nothing at all comes from nature in modern building materials, except for the raw materials they are made of, and I don’t see what is better about that. If you are afraid of organic materials, you can also build an ETICS with mineral wool. I would, however, have (maybe unfounded) concerns about moisture penetration.

A lot of advertising is done and a lot of semi-religious stuff is talked about. That’s why I would always focus objectively on physics and technology. The "each part takes over a function" from the sand-lime brick advertising is a priori just as much nonsense as the "monolithic is better" from Ytong or the "everything ecological" from Poroton (or all the wood stories). In the end, what counts are the properties of the masonry and the costs and how both fit the builder.

0.2 W/m²K with 17.5 KS and 16 mineral wool. It is borderline but acceptable. This results in about 700 kWh per year compared to 0.15 W/m²K here (that would be aerated concrete) - so about 40 €. It would just be annoying if the Kfw55 fails because of it... hence the waiting for the calculation - HT could certainly calculate it themselves somehow, but I would probably mess it up somewhere.

0.2 W/m²K with 17.5 calcium silicate and 16 mineral wool. It is borderline but acceptable. That amounts to about 700 kWH p.a. compared to 0.15 W/m²K with us (that would be aerated concrete) – so about 40 €. It would just be annoying if the KFW55 failed because of that... hence the waiting for the calculation – HT could surely calculate it themselves somehow, but I would certainly mess it up somewhere.

So if the money is there for clinker and brine heat pump, I would rather consider, instead of aerated concrete, a really well-executed ETICS with PUR and a high-quality plaster build-up or a curtain facade (in sandstone look *dream*) as an alternative to clinker.

I certainly won’t stick any PU on the wall - and bricks aren’t that expensive here.