Yes, we also wanted to install a walk-in shower. But I still don't quite understand what is meant by "joining pieces"
Under my old shower and bathtub, there was no screed after removal. So, where the new walk-in shower was built, the screed would have had to be redone and connected to the existing one. However, this can later lead to cracking at the transition, so I completely removed the old screed. PS: I just see you are also from OS. I am also from the district OS.