I have the same problem and was told the same from the OC. My building was also built in the mid-seventies, the crack appeared after a very large tree was removed, the crack goes up the wall about a half meter and along the ceiling one and half-meters, a building inspector wrote a report stating the removal of the tree was the cause of the crack, however, because the crack is not 5mm deep the OC believes it’s not responsible for the repair, around the crack the paint is also peeling.
Can you also advise me the information to take to the OC