Bond tiles with PCI adhesive on 3-week-old screed

Hello,

our construction company wants to install the screed (cement, not flowing screed) shortly before Christmas. The heating will then be put into operation only 3 weeks later due to the holiday period.
=> It is recommended to dry for 14 days, then use a heating program. Do you see a problem with the 3 weeks without heating?

Shortly before the heating is put into operation, the technical room is to be tiled. This would be done by a tiler separately commissioned by us, and he is supposed to use PCI adhesive because the screed is not yet dry.
=> Elsewhere I have read that PCI adhesive should only be used within the first 5 days, that is only on very fresh screed. Ours will then be almost 3 weeks old. How do you assess this? Will that be botched?
The construction company makes it easy with their demand; they do not have to assume any warranty for the tiles, as it is our tiler.

Finally, a question about the reason why it should be tiled beforehand.
The multi-utility introduction will be completed/sealed shortly afterward. And it is supposed to sit ON the tiles (on the floor).
=> Why? Why can’t you just wait until everything is dry and then tile around the floor introduction on the outside?

I find all this somewhat strange and have the feeling that it is only being done this way because it fits well into the construction company’s schedule...

3 weeks unheated is fine, ideally using a small electric heater to keep the house above 0°C. There are many PCI adhesives, your tiler probably means the very expensive Flex S2 bag, which is specified exactly for this case. However, with a conventional screed, you have relatively little water in the house anyway.

However, I would still only have the part of the room tiled that is absolutely necessary. Only a little water gets through the joints, so the remaining unbound residual moisture in the screed disappears correspondingly slowly. I did something similar with my full-surface waterproofing under the buffer. Only finished the 1m2 and heated the rest of the room according to functional + ready-to-cover heating.

Thank you for the reassuring information! The only remaining question is whether this special solution is really necessary just because of the introduction of multiple sectors. Are tiles really needed under the "overhanging edge" of 2cm? It would not bother me in the slightest if this "joint" is filled with joint material.

Whether this is necessary for the multi-division is hard to say from a distance. But if technology is to be installed in the utility room, it is nice to have tiles underneath. I refrained from doing that, instead I routed classic KG pipes DN 110 from below, inserted the cables, then sealed with well foam and screed, and tiled over.

No equipment will be installed otherwise, everything is mounted on the wall. It depends on the provider, ours only accepts multi-utility introduction, nothing [KG].