Tiles under and around the bathtub

Good morning, what is correct? The bathtub is to be installed on the bathtub carrier on 2 sides of the interior walls in the bathroom. Does the tiler have to lay tiles under the bathtub, that is, under the installation area of the bathtub carrier? Do the wall tiles have to be laid up to the top edge of the bathtub carrier or down to the floor behind the bathtub? The joint pattern to adjacent surfaces is secondary, as the remaining walls will not be tiled. Thank you for your answers.

Does the tiler have to lay tiles under the bathtub, i.e., under the installation area of the tub carrier?

No! Generally, a tub is installed during the shell construction even without screed. So pipes can/may also lie "exposed" there. In that respect, you couldn't tile there at all...

Do the wall tiles have to be laid up to the top edge of the tub carrier or up to the floor behind the bathtub?

The tiler tiles AFTER the tub installation, so he ends at the tub edge and ideally tiles the tub panel as well. The tile then basically overlaps the tub material. That's the only way it makes sense.

Just spoke with my plumber.
With the floor tiles, it doesn't matter technically. But if you can wait, it is more financially sensible not to tile under the bathtub.
Wall tiles directly above the bathtub should be installed only after the bathtub, as usually a bathtub sealing tape is applied there.

Hello home builders, how was the topic implemented in your bathroom?

Our tiler has agreed with the plumber that the area under the bathtub will be tiled, as the tile measurements for the partition wall behind the bathtub fit better that way. However, I have basically understood that it does not matter. Otherwise, it obviously makes sense cost-wise to tile only after the bathtub carrier has been installed.

Well, that of course depends on the height of the bathtub. For me, it wouldn't have made a difference. It fits neither exactly with nor without. But planning the bathtub according to the tiling pattern now also seems very monk-like. One could possibly have doubled up under the support beam with Wediplates or similar – but I didn't think of that in time. And the measurement the plumber gave me beforehand wasn't quite correct either. With the support beam, the bathtub should have actually been 60 high, but it was now 55.