Mold under screed in insulation layer

Hello, does anyone have experience with mold in the insulation layer beneath the screed? How can it be detected/measured? There are, for example, these mold tests for indoor air, where you place petri dishes for 2 hours and then evaluate the germ load after a period X. Does this seem useful? Other experiences or tips? Another question, can the edge insulation strips, the gap between floor covering and wall, be sealed with silicone (house completed 4 years ago)?

How can one recognize/measure this?

Open it up and check what the problem is.

There are, for example, these mold tests for indoor air where you place petri dishes for 2 hours and then assess the germ load after a certain period X. Does this seem sensible?

No, because this only measures the infestation of the indoor air. However, you still cannot conclude the cause.

Another question, can the edge insulation strips, the gap between the floor covering and the wall, be sealed with silicone, for example?

And what would be the effect and intention?

House completed 4 years ago

As already mentioned, I would determine the cause instead of fighting the symptoms. If the house has stood for 4 years and has been sufficiently heated and ventilated during that time, then construction defects are more likely to be suspected and not the missing adhesive tapes on the stapled panels (which are omitted in most buildings anyway). I guess it could be masonry problems or a defective horizontal barrier causing thermal bridges, or simply banal heating/ventilation deficits and the resulting consequences.

Yes, thank you. But opening it up is not so easy. The floor covering would have to be removed and the screed taken out, and the underfloor heating is in the screed. I also have no indication of where the problem is most likely to occur. Our animal roommates (other post) are in various places. If there is no mold problem, sealing the edge strips to eliminate the possibility of slipping underneath.

Sure, opening it involves effort, that goes without saying. It just depends on what the goal is. Root cause analysis or symptom treatment.