Screed drying - Incorrect drying program set

Why no drafts? Because then the surface dries faster while it is still damp underneath? Or do drafts cause cracks? With the CAF, you are supposed to ventilate at the latest after the 3rd day, if I understood that correctly.

okay thanks! no, drafts do not occur because everyone is on the east or north wall and the rooms are not connected.

. I would strongly recommend using dehumidifiers. With my screed, I wanted to save the costs, but I bitterly regretted it! At the latest after starting functional heating, I had to ventilate at least every hour to keep the moisture somewhat under control. I have wood-aluminum windows installed, which didn’t make it any easier.

By the way, the heating program with the electric heater cost me about 1000 euros in electricity, plus there was radiant heating.

"Why no drafts? Because then the surface dries faster while it is still damp underneath? Or do drafts lead to cracks?"
Answer @ "Wintersonne":
Exactly for that reason! In addition to crack formation, two other negative developments are to be expected,
1. the screed (cement, CA + CAF) loses the necessary water too early, which it needs for the chemical reaction at the surface (hardness is not achieved), and
2. cement screeds then tend to deform.
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"With CAF, one is supposed to ventilate at the latest after the 3rd day, if I understood correctly."
Answer:
That is only partially correct. One CAN start cross-ventilation with CAF after the 3rd day – but it is not mandatory!
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The hint from "rastlos" is also not a mandatory measure but involves certain risks.
Anyone who wants to save money by forced drying measures (condensation dryers) fundamentally misunderstands something!
Forced drying measures serve to bring an already sufficiently hardened screed, which either has a very large installation thickness or was installed as a poorly drying CAF with a very dense structure, to readiness for covering in a shorter time.
In new buildings, however, water does not only come from the screed but also from the wall plaster and masonry.
Here, intensive ventilation after the 21st day is normally completely sufficient.
Because the electricity costs are indeed not insignificant.
However, if calculated over a longer period, for example over 3 years, the use of a forced drying device can definitely pay off.
Namely because the apartment no longer needs to be "lived in damp," which in winter is always associated with higher heating costs (humid indoor air necessarily has a higher energy content than dry indoor air at the same temperature).
So: please do not "compare apples with oranges," but look at the overall picture. Certainly not easy for the layperson, admittedly!
Regards: KlaRa

The note about the dehumidifiers was not about saving money. The dehumidifiers of course consume a considerable amount of additional electricity.

I rather had the problem that despite ventilating every hour, I could not get the moisture out sufficiently. Without using the dehumidifiers, I would probably have had massive problems with mold. The wood-aluminum windows also cannot handle the high humidity in the long term.

However, my screed had enough time to cure before heating up. Unfortunately, the heating device was still in use at another construction site and only arrived late at my site. I suspect that is why my screed does not buckle at all. At a construction site of acquaintances, heating began immediately after 7 days. However, they now have the problem that the screed is severely buckling. They also skipped the use of dehumidifiers during that time and now have mold on their exposed roof truss and in some areas of the plaster - despite plenty of ventilating.

It is also very important that the insulation in the roof truss is already in place and sealed 100% vapor-tight. Otherwise, all the moisture migrates into the roof truss. It takes quite some time for it to dry sufficiently... If this is not considered and the insulation along with the vapor barrier is installed in the wet roof truss, one will probably be surprised after a few years that all the beams are pitch black with mold. The attic hatch should also be sealed 100% vapor-tight.

With us, the upper floor ceiling is sealed with the vapor barrier. There isn't even a floor hatch installed yet.

Did you wipe off the condensation with a cloth or a window vacuum cleaner?