ᐅ Seal a cut in the screed

Hello everyone, next step in the renovation/remodeling project. To lay new pipes, we cut a slot about 15cm wide (6 inches) into the screed.
In the pictures, you can see the slot before the new pipes were installed.
How can this slot be properly sealed again? There must be a few important things to keep in mind, right? I am confident I can handle the basic filling, but I would like to know which materials you would recommend. Thanks

A screed would be a good idea

Two bags of screed from the hardware store on top, and you're done.

Hmm, okay. You read so much on the internet, hence my question.

X_SH5_X schrieb:

Hm ok. You read so much on the internet, so that’s why I’m asking.

I know exactly what you mean.
You probably won’t be able to achieve proper impact sound insulation anymore.
And all that stuff with screed clips and treating the edges with resin—I’m not sure if that’s actually useful.

What type of floor covering will be installed on top?

There will be parquet flooring on top.
However, I should fill the bottom layer again with styrofoam between and above the pipes, right?