Wide shower pre-wall element / shower wall mounting

Hello,

we are currently working on our bathroom planning and have an open point here that I hope to clarify or narrow down. This topic has probably come up for some of you.

In a corner of the bathroom measuring 270cm x 280cm, we want to install a walk-in shower with the dimensions 120x90cm. On the 90cm side, a pre-wall element with a depth of 20cm will be built floor-to-ceiling for the concealed fittings, overhead shower, etc. Right next to it is a wall-mounted toilet, which also has a pre-wall element with a depth of 20cm but should only have a height of about 120cm.

Now the sanitary installer said that we should definitely have the shower wall element built wider than 90cm, to about 93cm, by the drywall builder in order to properly attach the shower enclosure here; otherwise, they do not assume liability for damage to the tiles that may occur when attaching the shower enclosure.

After consulting with the drywall builder, he said that this is completely unproblematic and that the shower enclosure should sit exactly flush, so 90cm is required. On the one hand, it looks less aesthetically pleasing, and on the other hand, it is never a problem to attach the shower enclosure.

We are now somewhat uncertain; the drywall builder's argument feels logical, definitely more aesthetically pleasing, and when I think about the installation, there are anyway brackets that are attached as an L shape to the wall and shower glass enclosure and then drilled rather into the shower rather than outward? So what could possibly break there? Alternatively, we are already considering having the shower enclosure installed later by another company; the exact model of the shower enclosure has not yet been decided...

Thanks in advance!

Attached is a plan, so you can probably imagine it better

I faced the same problem and was so uncertain about this corner that I built the shower in a different corner. Also, 20cm behind the shower is quite a lot. No, the bathroom is 2.90 by 3 meters. So very similar.

So behind the shower, wastewater pipes, ventilation, and heating are routed, also to the floor above, which is probably why the 20 cm measurement comes about, additionally due to the toilet next to it where the pre-wall element also has a depth of 20 cm.

We are still unsure about the width of the shower pre-wall element; unfortunately, no other position of the shower in the bathroom is possible. Now we are considering whether we might take a compromise of +1 cm, which probably wouldn't stand out so much and would give more room for later installation. The drywall builder also suggested placing wood underneath so that a glass wall can be better attached...

However, I am surprised that this problem does not seem to occur very often...

Does anyone else have an idea or experience?

Best regards

We have planned a shower enclosure over the bathtub. The consultant at the bathroom exhibition at that time pointed out to us that we should allow 10 cm depth, in this case width, for the installation. I can't say more about it because the installation has not yet taken place.

Best regards