Exterior walls made of aerated concrete, interior walls made of calcium silicate brick - yes or no?

Hi,

There are a lot of different opinions on the internet, but I wanted to ask specifically here. Our house is to be built with 42 cm aerated concrete (Lambda 0.08). Since I like to listen to loud music and we also have two children, the idea came up to use sand-lime brick inside. The house building company would include KS in the offer at the same price and said that cracking is not to be expected.

What do you think? Porenbeton and KS generally get along due to similar shrinkage tendencies. But there still remains a residual risk, right? Nevertheless, big companies build with this combination as standard (e.g. Arge Haus). What do you think?

(No, we are not using soundproof interior doors).

Interior walls made of KS are, to my knowledge, the only type of stone (regardless of whether the exterior wall is made of the same or a different material) exempt from the otherwise usual requirement to be tied into exterior walls. Therefore, KS as a material for interior walls is equivalent to being able to build exterior and interior walls as completely separate work processes (which is worth its weight in gold, since jumbo formats are regularly used for exterior walls nowadays). As a result, KS is an extremely popular and widespread interior wall material. I assume that it is often the case that interior walls are traditionally built in a mortar bed, even if the exterior walls consist of thin-bed "glued" Plan blocks. Given the widespread use, any problems should be well known. I would even expect that products have been developed from this. For example, in the form of special underlays for wallpaper in the transition corners where interior walls meet exterior walls. However, I have never heard of such products. It is also not uncommon to see a switch to KS in the reveal areas of porous brick walls; I am not aware of any associated plaster cracks or similar issues in this regard. Therefore, I assume that this material combination does not produce any problem phenomena.

We also use aerated concrete on the outside and calcium silicate on the inside, having had several general contractors directly offering this as well. I see no concerns there.

We build exactly like this. 42.5 cm aerated concrete on the outside and 24-11.5 cm calcium silicate bricks on the inside. However, we also have wall ties between the calcium silicate bricks and the exterior wall.

So far, no construction-related complaints – except for the chasing/grinding in the calcium silicate bricks.

Sound is already noticeably "absorbed" in the shell construction. So far, I can recommend it.

what do you use 24 cm KS interior walls for? On special request? With 24 cm KS, you build basement exterior walls.

As a load-bearing wall, we have the 24 cm sand-lime brick in the middle of the house. Otherwise, inside only 11.5 cm as partition walls or 1x 17.5 cm between the utility room and the hallway.

As a layperson, I assumed that this is correct.