Buying a house with a damp basement

I would very much like to ask you once again for your assessment. After disastrous experiences in terms of house construction, we viewed a condominium some time ago that we really like. Today, during the inspection with my father, it became apparent that the cellar is damp (calcium silicate brick). When we confronted the seller about this, by the way the owner of a credit consulting GmbH, he admitted it and explained that the damage was caused because the downpipe was torn off during the renovation measures. He is fairly sure that the problem has already been resolved but assured that it would be fixed at the latest by the handover and that a corresponding clause would be included in the purchase contract. How do you see this case? Could one have a warranty claim included in the purchase contract here? Should we rather immediately distance ourselves from the property? Is it even possible to get a cellar wall made of calcium silicate brick dry if a broken downpipe was the cause? By the way, this is a building from 1970 on a hillside plot. It concerns the daylight room in the cellar, which lies on the slope. If I have forgotten important information for the assessment of this situation, please feel free to ask. For clarification, I have attached the floor plan. It concerns the rear wall in the "Hobby-R" I thank you very much!!! We are now quite desperate because we feel that nothing wants to work for us in terms of purchase or construction.

If the property is still an option for you at all, you should conduct the second inspection as a purchase consultation only with an architect/civil engineer experienced in old buildings and renovations.

He should assess the building fabric, identify obvious defects, be able to specify the backlog of renovation, and also be able to evaluate all documents related to the [ETW] (reserves, structure of the owners' association, property manager, minutes of meetings, land register excerpt of the owner, etc.). I would not give more weight to the seller’s statements than his status suggests: real estate agents basically have no knowledge of the property and have no interest in it. You must obtain information about the property from reliable sources yourself.

For a house from the 70s, the building waterproofing in the basement can indeed be damaged or even non-existent. Floors on a hillside pose a greater challenge for the waterproofing of earth-contacting components. The masonry light wells without/with clogged drains and old, leaky basement windows can be additional weak points. Any renovation measures allegedly already carried out should be checked by the expert based on invoices or planning documents. If nothing is verifiable, in case of doubt, nothing has been done.

The energy standard of the building insulation remains to be checked in the [ETW], which will probably be rather modest. Thermal bridges must be particularly observed here (roller shutter boxes, continuous concrete ceilings as balcony slabs, window reveals) and the associated risk of mold formation caused by condensation. The overall impression of the house must be included in the evaluation, e.g., also the type, age and condition of the building services, especially the heating system.