Humidity in basement apartment

Because of the mold in the apartment, I found out today that there has been mold there more often. However, it apparently was not to this extent. I got in touch with the former caretaker through indirect means. He painted over it dozens of times and used mold remover. The seller was aware of the problem. She confirmed to me before the sale, in front of witnesses, that there was no mold there.

Would something like this be a reason to contest the purchase due to fraudulent misrepresentation? Both the caretaker and the witness from the sales conversation would testify to this in court. And the former tenants could easily be found and they wouldn’t say anything different.

What a fuss over such an apartment.....

The right contact person is a lawyer.

About the mold: if it’s not the heating, I suspect poor insulation. Since it is underground, either groundwater is present or the cold earth is against it. Then the warm air with a lot of moisture comes in and the moisture condenses on the cooled wall. Since in the photos the mold appears to be completely in the lower area, it might be that the insulation was not applied deep enough.

A leaking heating system can, but does not have to. It also often loses pressure due to a broken expansion vessel.

Thank you for the confirmation Mold in the apartment is almost never due to "incorrect ventilation"

You cannot generalize it. In old buildings where new windows are installed that suddenly are airtight, the heating and ventilation behavior must definitely be adjusted. However, it is always an interaction with the building fabric, I agree with you on that.

In the meantime, an unsuccessful leak detection was carried out and a rainwater drainage channel was inspected. According to the expert, the next step is to excavate around the house to check underground pipes and the building insulation for damage.

Unfortunately, the building insurance no longer covers this. The excavation will cost approximately €1,000 plus someone to inspect the exposed area. Does anyone know if the owners' association will cover this? Or do I have to pay for it myself and possibly later claim the costs from the owners' association if damage to the individual property is confirmed?

The issue with rescission due to fraudulent misrepresentation will be difficult. This janitor told an acquaintance that he painted over it about five years ago because there was slight mold. This was done on the instructions of the seller, who told me there had never been mold there. However, he refused to give me his contact details and says he will not testify in court because he is afraid of the seller’s son. Furthermore, it would likely be a case of one person’s word against another’s. I am currently trying to locate the previous tenant in the hope that she can also provide some information. I know the block where she lives and her name. I have to check there, as she is not listed in the phone book... very vague.

I am still hoping that a fixable issue will be found that can be remedied at the expense of the owners' association.

Today the excavations around the building begin. This was already found at the start of the work.