Bathtub - GU does not want to set it lower

Hello everyone,

we have a large 80x180 bathtub in our bathroom. The tub is placed in front of a window with a sill height of 69.5cm from the finished floor level. The tub is about 60cm high. It is set on a tub support on the finished floor. The construction manager won’t change that, even though I pointed out that the tub is too high for us and that we would prefer to place it on the raw floor. He says that it must only be placed on the finished floor so that water damage does not flow into the building structure.
Now I planned further and realized that the inlet fittings will have no space left, since there is only a few centimeters of space between the top edge of the tub and the window sill height. So the faucet cannot be placed where it is planned according to the execution drawing.
After I confronted the construction manager with this, he came back saying that he will have it checked what solutions there might be. For example, leaving out the inlet fitting and instead realizing the water supply over the overflow. This will cause additional costs that we would have to bear!

I am actually not satisfied with this at all! Someone else who is also building with the general contractor is having their tub placed on the raw floor – apparently with a different construction manager.

My question to you:
What arguments could I give the construction manager to have the tub placed on the raw floor anyway? Are there regulations or is it state of the art that it must only be placed on the finished screed, for example because of "watertightness" in case of water damage?
Is such a "makeshift solution" to be paid for by the client or is it a problem of the general contractor? According to the construction manager, this is "your house, which is individually planned and built, so your wish and your costs"...

Edit:
We set the sill heights as high as possible. Higher than 69.5cm is not possible because of the window and knee wall.

Ultimately, it is a contractual and liability issue. The general contractor can take the position that you want the wrong bathtub for your house. I do not know the communication between you and the site manager. If I understand you correctly, you want your bathtub including fittings to fit and the window to open. In your question to the forum, it is about how to get the general contractor to place the bathtub on the raw floor. This is not necessarily goal-congruent and excludes other possible solutions.

Are there any possibilities to do without the position of the tub under the window or to raise the parapet?
If you build with GU, it may be that you have little say in this regard concerning the "rules of technology."

Ultimately, it is a matter of contract and liability. The general contractor can take the position that you want the wrong bathtub for your house.

This combination has actually been fixed since February 2019 and was finalized at the latest since the selection process in August 2019. In the execution drawings from September 2019, at least the wastewater pipes were drawn in, and the planning department should have noticed that there was no space for the inlet fitting.

I do not know the communication between you and the construction manager.
If I understand you correctly, you want your bathtub including fittings to fit and for the window to open.

Yes, that’s how it looks.

Your question in the forum is about how to get the general contractor to place the bathtub on the raw floor.
That is not necessarily goal-congruent and excludes other solution possibilities.

The other solution possibilities are currently being examined, which I do not know as a layperson. I will probably receive suggestions for solutions. Until then, I would like to find arguments to have the bathtub placed on the raw floor. After all, a fellow general contractor client advised me “not to give up easily.”

Are there options to do without the bathtub’s position under the window or to raise the parapet?

Unfortunately not. The planning is already fixed and placing the bathtub in front of the window makes the most sense due to the low parapet height. Raising the parapet would probably only be possible by lowering the windows. The windows are sized 1.76x0.76. We also had to remove the shutters because of the ceiling height/roof.
With a lower knee wall, I would probably have planned a roof window above the bathtub.

The argumentation of the general contractor is nonsense. If the tub leaks, the water will flow into the structure anyway. This very unlikely failure cannot be the basis for planning. In every project I know, the tub support stands on the raw subfloor. The screed is stopped. Before installing the support, the tiler should still waterproof. Ultimately, it is the client who decides what they want and consequently pays for.

And by the way, a nice side effect: The entry height is more comfortable.