concrete interior wall

[Mattias Mattsson]

Hello!
I am renovating a basement room, built just in 1969. The walls are made of concrete, and there are some cracks in them. I don't know what that means. I don't see any on the outside of the house. I have scraped in them, and under the concrete, there are black leca balls. What is that!
How can I best fix this? Repair mortar? How much should I chip away?

Grateful for answers

 

[Stefan N]

Your wall is built of lecasten that is plastered.

 

[Mattias Mattsson]

Your wall is built of lecasten that is plastered.

Thanks for the response!
What's the smoothest way to fix the server? Chisel and fill with repair mortar?

 

[Stefan N]

Cracks of this type are often difficult to get rid of as they have occurred for a reason. Try chiseling a bit so that it's firm at the edges, then water and polish with some mortar afterwards.

 

[Mattias Mattsson]

Thanks again!
Is there anything to be worried about? If it's just cracks in the plaster, it shouldn't be a major threat to the construction.