I have no idea what kind of wall this is. Both my walls that are near radiators have this bubbling plaster look. I have read that painting with temperature differences may cause the bubbling (such as painting in the winter and then the heater is turned on). It was recommended to paint in the summer when the windows can be left open to equilibrate the temperature as the paint dries.
Not sure what to do about the bottom. How do I repair this wall? It seems to be paint --> very thin layer of plaster --> concrete. Does the whole wall need to be taken down? Should I just scrape off the plaster and respackle? I was thinking of sanding down the bubbles, respackle, and repainting. Does the whole wall need to come off?
Bottom of wall
Top of wall