Y-Tong (aerated concrete) - quality building material? (sound insulation!)

The hazardous waste is then inside the brick. They did tell him about the options. Ytong plus curtain facade facing the street. A special sand-lime brick from Sellia is also suitable as a clinker. That is a nice option. With soundproofing.

Bricks also come with perlite, not hazardous waste

One more thing, bookstar, the BU seems to build with sand-lime brick or Ytong, not with bricks. The further north you go, the less common bricks become, why, that is not justified, it just is. While in BW you can hardly find a BU with Ytong. Objectively considered, both systems work. Both are similarly expensive, both have the balancing act of sound insulation vs. thermal insulation. The more insulation, the worse the noise.

Klinkern ist leider gar nicht unseres. :-(

But double-layered construction is simply a great method when it comes to sound! Here is a 1990s building with timber frame construction, but with insulation and a clinker curtain facade. According to the data sheet, it is thus a 56dB facade. And it 'sounds' like that inside as well...

In another forum post, someone wrote the following: "ETICS with sand-lime brick/high hollow brick or aerated concrete are similar in price. It depends on what the shell builder uses more of."

My mantra is mainly: the stone that the contractor has the most experience working with is overall the better choice than a stone with, in itself, more optimal properties but unfamiliar to the processor. The same applies to wanting to "re-educate" the contractor between the "belief" in monolithic or composite wall constructions. At every corner and every connection to other components, it pays off if the processor is "used to" their product.

2) Exterior Ytong 36.5 and interior sand-lime brick: is this variant still being considered?

If you mean deciding separately for flesh (solid) or fish (porous) for exterior and interior walls: yes, this is a gladly considered combination. However, if you mean an exterior shell of Ytong and an interior shell of sand-lime brick: I would doubt that as the "Columbus' egg."

Alternatively, there are also aerated concrete manufacturers offering a combined stone:

I have not come across this product yet; what is it called on the market, and are there one or more providers?

Does it make sense to build the exterior of a house with Ytong and the interior walls with KS stone for sound insulation inside the house?