Screed does not dry after 10 weeks of laying + heating program

Hello,

on 12.07 we had 7 cm of cement screed installed throughout the entire house. Because it wasn’t really urgent, we only started the heating program on 24.09. So it actually rested for a good 11 weeks.

The "roughest" part of the water is thus out, now it’s time for the floor coverings, which is why the Hotboy was turned on.

We have now heated according to the "program" of my heating engineer until 11.10, in consultation with the screed installer. I understand that this is not the "standard program," which I personally find desirable, because no new building still needs 55 degrees flow temperature today. The screed will never see that with our heat pump. MAX flow temperature according to calculation is 35 degrees.

We heated as follows:

1: 30 degrees
2: 35 degrees
3-5: 45 degrees (so the screed would experience it once)
6-12: 35 degrees
13-17: 40 degrees (after first quick test still too wet, therefore flow temp raised again)
18: 35 degrees
19: 30 degrees

But that should (hopefully) not be the topic. Much more, I am still puzzled that after such a long time, my tiler still finds a CM measurement unnecessary because his moisture meter (from GANN) still shows 65 digits. I understand the idea of testing beforehand.
But I don’t understand why it’s still all so wet?

Yes, I ventilate 3-4 times a day by cross-ventilation. I have 2 hygrometers in the house and ventilate as long as the humidity rises again. So actually always about 10 minutes. I don’t want to connect several construction dryers to the Hotboy now; that thing already heats you into bankruptcy anyway.

My questions:
Should I basically leave the windows tilted? Also at night? Or tilted + shock ventilation all day and closed at night? Still just shock ventilation?
Not ventilate at all when it rains? Warm and "full" air with water should go out, right? Is there a minimum flow temperature one should run?

Aside from the "special program," what else could it be?

Thanks to you all.

Aside from the "special program," what else could it be?

Only the special program. This is roughly what the normal program looks like (3-4 weeks after screed installation).
You are far off in terms of temperatures, but especially also in terms of time. No heat pump installed yet that you could simply run continuously at 35 degrees? Just another 1-2 weeks.

No, it's a brine pump and the heating engineer always tells me the same story about frozen collectors, the ground being "dead" for winter, etc. He wants/would only run it with the Hotboy. Apart from the fact that he even finds time to set it...

Does the "lying time" already count when you exit the heating program, or is that why it starts on day 21? As I said, I also will not run 55 degrees into the screed! Then I guess the only option left is to wait?

No, it's a brine pump

Then better not heat up with the heat pump - but 30 degrees should be possible as in winter.

Does the "resting time" already count when you extract the heating program, or why does it start at day 21?

Yep - wait at least three weeks. So day 21 as the start.

Thank you. But as I said, he won't be coming to the position anytime soon anyway, so the hotboy stays.

I just read in another thread what is "running through" here with the hotboy.
I have only used about 100/kwh in 24h today at 30 degrees flow temperature. Does it make sense to throttle the power from 21KW at 30-35 degrees flow temperature?
Or is that even helpful for faster and more efficient heating?

Hello " " For heated screeds, according to the regulations, functional heating and then readiness-for-cover heating are foreseen. Basically, readiness-for-cover heating serves to free the screed mortar from its excess mixing water to such an extent that no damage occurs after covering it with any type of covering (textile, elastic, or wood). The obligation to check the readiness for covering lies solely with the floor installer. With 65 Digits according to GANN, practice simply shows that a CM test should definitely be carried out. This digital value is by no means in a range where one should shake their head about conducting a CM measurement. At this point, I also consider forced drying to be exaggerated and unnecessary given the 65 Digits. Have a CM test carried out, even if the second measurement involves costs (only the first measurement is generally already included in the offer costs). Whether to ventilate continuously or not—no one can give you a reasonable answer to that. This is because the nights are currently getting cold, the outside air cools down, and the relative humidity inevitably increases outdoors. It would not lead to (drying) success if moist outside air is allowed in through tilted windows. Well, a cement screed only noticeably absorbs moisture at about 65-70% relative humidity. But the situation is not very suitable for expecting the screed to dry, even if it will not have harmful effects. Please do the following: Buy yourself a hygrometer if you do not already have one. Place the hygrometer in a representative room, centrally, close all windows, and check after about 5-8 hours how or if the value changes. For example, if you read a value of 65% relative humidity, you would already have the floor installer with their 65 Digits "in your pocket." The screed is ready for a CM measurement. Without any doubt. -------------------- Continued success: KlaRa