Tiled shower floor - sooner or later trouble due to silicone joint?

Only that with shower trays the joint does not "stand in water" because it is higher. With tiled shower floors, the water sometimes stands at these joints (probably always at the rear joint where the drain is).

With the shower tray, only the water that runs down the wall "stands" there. The actual water does not stand at these joints.

That is fundamentally not correct either. The water does not run toward the joint because the slope of a tiled shower goes toward the channel or drain. So from all four edges of the shower away from the wall (joint)! If water "stands" at the joint, at least the slope is incorrect or the drain is clogged and water stands 1 cm high in the shower :oops: The drain often isn’t even sealed with silicone but only grouted. Take a look at system images/diagrams of drains, then you will see that even then nothing happens there.

And whoever is too afraid that the silicone joint will not withstand the loads should ask the craftsman to apply an MS polymer joint. The material should be prepared in advance; he does not have it with him. But this must be done at the beginning; later it is no longer possible. If there was silicone in it once, it must always be silicone; nothing else adheres reliably there anymore. Our silicone joint was applied in August 17 and is still intact.

As already mentioned. The tiles are only the covering on the waterproofing - the joints between the tiles are not watertight either. The biggest disadvantage of the tiles is the deposits (dirt/limescale), it simply does not look nice for long, especially if you have very small tiles. The advantage is the better integration of the underfloor heating.

The biggest disadvantage of the tiles is the deposits (dirt/limescale), they simply don't look nice for long,

I can confirm that. Many neighbors have a white residue. We don't, although our tiles are dull and uneven: we wipe down walls and floor after showering.

As already written. The tiles are just the covering on the waterproofing - the joints between the tiles are not sealed either. The biggest disadvantage of the tiles is the deposits (dirt/limescale), they simply don’t look nice for long, especially if you have very small tiles. The advantage is the better integration of the underfloor heating.

I don’t understand that either. I can simply place the shower tray on the screed, right? Sure, it will then be 2-3 cm higher than the tiles, but then the underfloor heating should still work, shouldn’t it?

That's not true either. There are no heating coils in the shower. The huge advantage of the tiled shower is complete accessibility. We have it so that even in the case of care, one can enter there with a chair.