Mold behind the baseboard

Hello,
we messed up again.
We bought a two-family house, where the lower apartment is at ground level. The floor slab is about 10 cm in the ground. We wanted to renovate the lower apartment and had to find that there is mold behind the baseboards throughout the entire apartment, not just on the exterior walls. In addition, the plaster on the walls in this area is literally falling off. Above the baseboards, none of the mold is visible. The bathroom is also not moldy. Our youngest son, who is supposed to move in there, is asthmatic, so it is unacceptable for him to live there under these conditions!
Where can this mold come from?
Is there anything that can be done to make this fungus disappear permanently?
Thank you very much

Hello,

We have bought a two-family house...The floor slab is about 10 cm in the ground...there is mold behind the baseboards throughout the entire apartment, not just on the exterior walls. In addition, the plaster in this area is literally falling off the walls...Is there anything that can be done to make this fungus disappear permanently?

Your question cannot be answered as it is, since you have not written anything about the age, the masonry, etc. of the property, nor about the contract design. Is there a value appraisal?

To be on the safe side, I recommend you seek professional help; hire a building expert whose field of expertise includes existing properties and their assessment. Only then will you know for sure how to remedy the mold infestation and also whether the seller may have concealed one detail or another. Costs in the range of € 600-800, depending on the scope, plus VAT.

Kind regards

Hello. The house is 40 years old, the masonry is HBL bricks. There is no appraisal. Well, the seller wasn’t completely honest after all! He confessed to us today that three years ago there was water damage in one of the rooms downstairs. Apparently, the bathroom above was somewhat leaky and water ran into the "basement" room for several weeks. According to him, the entire carpet was soaking wet!! The water damage upstairs was repaired and downstairs, in that one room, a hot air blower was set up for 8 days. Strangely, this room is hardly affected by mold. All the others much more so. We now suspect that the water back then did not remain in the one room but got into the insulation layer. But how do I know that this insulation layer is not soaking wet and even if we dry everything now, the mold won’t grow again in 2 months??? Thank you very much

Hello,

Only, how do I know that this insulation layer isn’t soaking wet and, even if we dry everything now, the mold won’t bloom again in 2 months???

Only by – as already advised – commissioning expert help; an expert has different types of measuring devices with them, including for measuring the moisture content of the masonry. With a verifiable and thus written report, you can then also confront the seller if major renovation measures arise; without such a report, it would be hopeless.

Kind regards

That is probably true, we will do that.
Many thanks
Regards
Petra