Aerated concrete outside and sand-lime brick inside?

We would have the exterior masonry done with aerated concrete PPW2 0.35 (probably 36.5 or 42.5). For the interior masonry, we could choose between PPW6 or calcium silicate and tend to favor the CS. The construction company has already pointed out to us that there is quite a bit to consider when connecting the exterior walls to the interior walls, but this is basically possible without problems. Now I have often read that aerated concrete outside and CS inside is not a problem and if the company also knows that certain things need to be observed at the connection (unfortunately I did not quickly understand exactly what is done there), then that should be fine?

CS interior walls compared to PPW6 interior walls would mean a higher heat storage capacity or, of course, cold storage capacity in summer. Also better sound insulation. Therefore our desire to use CS as interior masonry. Furthermore, things can be attached more easily to it.

Where is the question?

Mix PB outside with KS inside, if the company knows about the topic, no problem? Or better to stick with PPW6 and stay within the system? What exactly is important now when mixing PB outside and KS inside?

Hello,

I did it exactly the same way with 36 cm aerated concrete exterior walls and 24 cm calcium silicate interior walls. Since I have the office in the house and sound insulation was important to me, they are all 24 cm. For the statics, 17 cm or 11 cm would have been sufficient.

You have to be careful with the connection. Normally, the walls are interlocked. In mixed masonry, however, they are butted squarely so that the stones, which expand and contract differently, do not form cracks. In addition, since the calcium silicate has a high thermal conductivity, the points that are interlocked with the exterior wall would affect the insulation and create a thermal bridge.

Since the interlocking serves stability, a connection must be made instead of interlocking when butting. For this purpose, wall ties are placed in the joints. That's basically it.

Faith intertwined is often no longer much like this... but here a lot is also mixed - so PB outside and KS inside.

So we have PB 40 exterior walls, load-bearing walls are made of 24 Kalksandstein and the rest are made of 11.5 PB.