Removing paint from house 1900

The house is a basement room. Below is a rock cellar. Walls are 2 meters thick. Fernunterricht Sockel is only thinly plastered. The base stands out. Under the plaster is slate rock. Complete renovation would be too costly. Demolition would cost 10,000 euros. It is only supposed to be simply refurbished from the outside. The plaster has been there since 1890. Only a few cracks, I plastered the base about 2 cm thick. But it is dry from the outside. It may look damp in the photo. Just want to add a little plaster. New paint on it. For the next few years.

No, it doesn't look damp, and you can't feel it either: it evaporates superficially outward. The paint only peels exactly where the evaporation takes place. The moisture carries dissolved salts, which crystallize when evaporating and cause plaster/paint to flake off. Plastering the base was not the best idea; previously, the paint above was certainly still intact, but the base looked terrible. As I said: just paint over it, after at most 1-2 years it will look exactly the same again. Or clean the base completely down to the stones at the bottom, then it can evaporate and crystallize down there where it doesn't bother anyone visually, and everything stays nice above.

Except for the stones? But I still have to plaster over them with something, I can't leave the slate bare. The paint hasn't peeled off any further so far. The coating has been on for about 100 years. The paint that is peeling off is also on the backside where the stone is exposed.

My question was just how to remove the peeling paint, or if I need to remove all the paint. Everything else like removing the entire base would not be financially feasible and is also not necessary. It just needs to be refreshed a bit. It is unoccupied... and I am only fixing it a little from the outside. If anything, I would just paint over it again after five years. It wouldn’t be that bad. I filled the cracks with acrylic. The house is built on a rock cellar. The cellar inside is relatively dry, further back about 20 meters into pure rock.

The info that it is an uninhabited house, which is only supposed to be spruced up temporarily, might have belonged more in the opening post. Then just paint over it, and if it peels off again, then so be it. As said before, go over it first with the pressure washer and possibly a wire brush. Then you've covered most of it.

I'm still new here sorry