Masonry is crumbling! Is there a risk of collapse?

Good day. We recently bought a single-family house and are currently renovating the attached kitchen. When removing the plaster, the lower masonry started to crumble. It can be removed relatively easily with a hammer... Therefore, I suspect that the former exterior wall might be unstable. Should I have a mason take a look at it? Best regards, Jens

When was the house built? It looks heavily like an "older" construction year, as for example plaster with straw/manure inside can be seen. Additionally, the wall structure is somewhat adventurous, which, however, in the case of a possibly quite old house, only needs to cause limited concern. That the plaster and also the mortar are quite crumbly would be normal in this case (preferably with a higher sand content).

What makes me most suspicious is that you can hardly recognize a real wall, but only individual stones. But if the house, as I would suspect, is already quite old, then that is only conditionally worrying. Clarification by a professional, if available, certainly can’t hurt.

The year of construction was given as 1972. However, we and the building expert suspect that it dates from the 1950s. Correct, I also do not see any proper masonry, but only 3 stones between clay and other stuff

1972? When I look at that, I would rather say post-war period

I also recognize remnants of this blue plaster (Leimfarbe) there. That was probably widespread in the past. I would definitely say before 1950 and also tend towards the post-war period.

1972? When I look at that, I would rather say post-war period

I agree. But even according to the energy certificate, the house is from 1972. I will probably have to inquire with the municipality about the official year of construction. Because in my opinion, according to the building plans, the house was only last remodeled in 1972. And now this is being taken as the year of construction....