The reason for the poor operation of ventilation is most likely that someone from the above residents deformed or completely blocked the ventilation mine, setting up a niche in it for the installation of a refrigerator.
This is diagnosed in a simple worker-peasant way: you climb the roof, approach the head of the ventilation mine and throw a large, heavy, sharp break in it. If the windshield is not damaged, the breakout flies to the first floor and blows about the foundation of the house. And if he is stuck in one of the built-in refrigerators, then the diagnosis has been confirmed and can be filed in court on the subject that damaged the common property of the residents of the ICJ. The Chaus (YUK)