A wild "estrich" appeared. It's super effective! Basically, the discussion was already pointless before, we only had a short afternoon to go and check out the floor snakes. The plan was that the screed would go down directly after the underfloor heating was completed, so one day later. We had hoped to catch the underfloor heating company and also take a look upstairs, but unfortunately our timing was bad; they were already finished when we arrived. At first, our timing was better, but at the moment we've missed everyone exactly on the day we went for the third time in a row. Something always happens. It's as if little house elves are at work. When I posted the photos of the floor snakes, the screed was probably already poured or just being poured. So we will see; the first winter will show. I remain optimistic anyway. I still have enough time to get annoyed about botched work if there really is botched work. If I do that beforehand, it's always bad for my blood pressure.