Concealed installation / pipe laying in screed

Hello,

we are building a house through a developer.
In the bathroom, we want to install the shower almost flush with the floor (flat shower tray, "recessed" in the screed).
According to the developer, the installation of sanitary fixtures + pipes should be done via a pre-wall installation.
A pre-wall behind the washbasin, the toilet, the bathtub, etc. makes sense to me.
But do all supply lines really have to be installed in a pre-wall? It should also be possible to lay the pipes (depending on the distance) in the screed.
I want to avoid having these unsightly "skirting boards" throughout the bathroom.
According to our developer, the pipes cannot be laid in the screed because underfloor heating is planned.
However, I have heard from other plumbing companies that precisely because underfloor heating is installed, the screed has a corresponding height and thus the pipes could be easily laid.
?!?
I don't have to lay the underfloor heating all the way to the "edge" of the room, do I? Are there certain norms, etc., that need to be observed here?
House is still in planning / construction of the shell has not yet started.
Unfortunately, the sanitary company has also not yet been decided.

Hello,

In the bathroom we want to install the shower almost flush with the floor (flat shower tray, "recessed" in the screed).

Why don't you just build it flush with the floor - without a shower tray?

The sanitary fixtures + pipes are to be installed according to the developer via a pre-wall installation.

That is correct.

Pre-wall behind the washbasin, the toilet, the bathtub etc. makes sense to me.
But do really all supply pipes have to be installed in a pre-wall? It should also be possible to lay the pipes (depending on the distance) in the screed. I want to avoid having these ugly "baseboards" all over the bathroom.

I don’t understand what you mean?

According to our developer, the pipes cannot be laid in the screed because underfloor heating is planned.
However, I have heard from other plumbing companies that precisely because of the installation of underfloor heating, the screed has a corresponding height and thus the pipes could be easily laid.?!?

How does he want to create the necessary slope for the shower wastewater?

I don’t have to lay the underfloor heating completely up to the "edge" of the room, do I? Are there specific standards etc. that have to be followed?

Under the bathroom, under all objects – including under the shower – or how should I understand this question?

Kind regards

Question: In one corner of the room is the shower - flat shower tray, should be installed flush with the floor - then I have to bridge 2 meters along the wall to the shaft. Do I necessarily have to install a pre-wall between the shaft and the shower for the pipe installation? The screed is supposed to be about 14 cm "high" - as underfloor heating is planned. Second question: Can a pre-wall installation be executed only as high as the screed? The pipe cannot be positioned higher than the finished screed height, as I need the corresponding slope.

Hello Gerda,

Question: in one corner of the room there is the shower - flat shower tray, which is to be installed flush with the floor - then I have to bridge 2m along the wall to the shaft. Do I absolutely have to install a pre-wall installation for the pipe laying between the shaft and the shower?
The screed should be about 14cm "high" - as underfloor heating is planned.
Second question: Can a pre-wall installation also be executed only as high as the screed? The pipe can't be laid higher than the finished screed height, since I need the corresponding slope.

Everything I answer to you now can only be wrong => I am not a heating/plumbing specialist and do not know the exact floor construction; approximate figures are unfortunately not sufficient. Therefore, I would recommend that you get a second opinion from a sanitary installer and then discuss this information with your provider.

Kind regards