Heating of screed ready for covering

Then it seems that a fast screed is also being installed with us. Our BL mentioned that we should ventilate several times a day for 2 weeks. The construction service description states that a drying time of 3 weeks is planned. Or is that standardly included?

I reminded the GU of their deadline for completion, which automatically brought up the Schnellestrich. The Thermorapid is almost 20 times as expensive as cement, but that should not result in much more than a 1,000 to 1,500 euro difference for our 200 m2 living space. If the number is correct, it would ALWAYS be worth it to me, especially since the Thermorapid does not crack either. The parquet layer could glue directly without leveling compound.

At the next house, we all know better

Yes, the controversy surrounding the CM measurement is well known. And it is also easily recognizable to the layperson. In my opinion, the measurement can also easily be (manipulated). The screed should actually be taken from "further down." But if the tiler, for example, wants to keep his appointment, then suddenly a few "grains" from higher up slip into the measuring device. Another person doesn’t have time anyway and digs down all the way to the bottom so that he can tell the customer "sorry, let's talk again in 2 weeks."
I work with statistics professionally and this makes my hair stand on end.

a) How realistic is it to meet this deadline with our current situation and planned measures?
b) Or with which additional measures can we meet the deadline?
c) If the deadline is not realistic, what would be realistic?
d) asked differently: are there any charts or similar showing by how many percentage points the CM value decreases over a certain period during the readiness heating on average or under optimal conditions or or or?

Hello "Faydie". Your questions can be answered as follows:
If the functional heating has already taken place, then the possible thermal stresses, which a screed is later exposed to in the service condition, have already been achieved.
This means: you can heat the screed whenever and however you want if needed.
Screeds also dry without additional heating, that is nothing new.
Underfloor heating accelerates the drying process.
What makes sense: place a hygrometer in the room, run the underfloor heating (as it is currently only on standby to avoid reaching freezing temperatures) with 25°C flow temperature and watch whether the hygrometer reaches a value >70% relative humidity or not.
If the value is significantly undershot, it can be assumed that the maximum permissible residual moisture of 1.8 CM-% is undercut, then there is very likely nothing preventing the tiling work in February.
If you want to carry out a manual test:
Lay about 1m² of PE foil in the middle of the room on the screed and place the hygrometer under the foil.
Tape the edges of the foil securely with good adhesive tape and heat the screed at approximately 30/35°C flow temperature.
After 24 hours, check the hygrometer and also whether any condensate has formed under the foil.
If condensate drops are visible, the screed is certainly still too wet.
If no condensate drops are visible, the hygrometer should not show a value >70%.
This "manual test" is not made up but is a fairly reliable test with meaningful results!
I use it regularly when CM measurement marks were omitted (or forgotten) during screed installation and a reliable statement about the residual moisture of the screed is required.
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Regards: KlaRa

so, because I always hate it when a post doesn’t have a proper conclusion when googling: today’s CM value is 1.9. What did we do? Starting from 02/01, we slowly turned the underfloor heating back on. From 02/02, underfloor heating was on full blast until 02/05 inclusive. From 02/06, underfloor heating was only at 32 degrees because otherwise the plasterer couldn’t work. From 02/02, one condensation dryer and one fan per floor. Now we will let the underfloor heating run over the weekend. Starting Tuesday, the wall tiles will be installed. By the time the floor tiles go on, we’ll easily have 1.8. Thanks to everyone

KlaRa: we tried your test yesterday and were therefore in good spirits today