Fast-setting screed on wooden beam ceiling, experiences?

Hello guys,

I am once again working on a small renovation at the house.. the kitchen is currently being renewed.

For the following two reasons, I ripped out the floor
- because the old heating pipes (unfortunately a single loop system) were already 50 years old
- and the rest of the floor structure (height) of the apartment had already been renovated, so I had a 3 cm step to the kitchen.

Previously, a "normal" screed was laid on foil and thin Styrodur boards, but it was already severely cracked, which I want to prevent as much as possible this time.

Originally, it was planned to apply a cast asphalt, but now it would cost a hefty 2600€ for 12 sqm (213€/sqm).. which is too expensive for me.

For time reasons, I would like to apply a fast screed by the company Baumit (allegedly usable after 3 days).

My questions to the experts here..

- how to best design the structure? Insulation - foil - Lewis boards - screed - impact sound insulation - parquet (16mm)
- how do I best protect the copper pipes from contact corrosion? I was thinking of such fiberglass pipe insulation see picture
- how thick should I make the insulation, I don't want to burden the joists with too much weight..

Thanks in advance

Hello questioner.
From the (informative) middle photo, it can be seen that the old screed construction had a buildup height of around 10cm.
If the not yet insulated/encased copper pipe is provided with appropriate protection, that is, an encasement, then 10cm - 6cm = 4cm buildup height remains.
That is practically "quite little".
I suggest compensating the entire area (after encasing the exposed copper pipes) with a lightweight screed, Thermocell or similar, up to the top edge of the encasement.
On this, a load distribution board made of HDF or MDF, impact sound insulation 20mm, PE foil, and on top of that a prefabricated screed made of gypsum fiberboard or as an OSB board.
This should then meet all requirements.
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Regards and good luck: KlaRa