Damp basement from inside or outside?

I would also wait a few more months to see how the moisture conditions in your walls and around the renovated shaft develop. The most obvious damage has already been repaired, now it takes some time for the affected building components to dry out. Perhaps a construction dryer would also be helpful? If you still find water in the basement despite the renovated shaft or if mold starts to develop somewhere, you will need to search for the cause together with an expert - maybe other inspection or house connections are also leaking, or there is damage to the roof drainage (not necessarily on the house, maybe in the piping that drains water away from the house below ground level)...

I would search for a publicly appointed and sworn expert for buildings near you using the usual search engines or ask around in the neighborhood / the village if anyone can recommend someone.

Ok thanks. So I don't need to worry about the chipped plaster on the exterior wall? Can't that damage the building fabric? I think I read that you can theoretically leave damp basements damp. Our other basement rooms are dry. In other words, even if the wall in the heating room were damp, could you just leave it like that without an expensive renovation from the outside?

The basement has been standing for almost exactly 50 years, it can easily last that long again. If the moisture in the room doesn't bother you and you don't want to store anything susceptible to mold there, you can just leave it as it is.

Exactly. If the chipping on the plaster bothers you, you can also consider removing the plaster (maybe there is too much gypsum in the plaster) and replacing the old plaster with a lime plaster.