Closing a Balcony with a Canopy

Hello, A. My neighbor's balcony on the fourth floor is above my balcony in a stepped shape, which is shorter and leaves me half a balcony for the sukkah. My neighbor claims that by installing a pergola that protrudes slightly outside the facade and also installing a cover above that also protrudes to the end of the pergola, I am preventing him from having the limited view from the facade of his balcony towards the yard/parking more than it is already blocked, according to him, and he claims that anything protruding outside the balcony area is the use of a shared space that requires consent and should not cause disturbance. It is important to note that in any case, the main space is blocked for him at the facade due to the shape of the balcony, but from the side, he has an excellent view. B. According to him, the cover gets dirty, and I need to ensure its cleanliness as it is adjacent to his balcony railing and is disgusting for the users of the balcony. On the other hand, I agreed that I should install spikes and the like if pigeons settle there, but since the place is open and full of sun, they do not settle, and there is no need. However, a bird just dropped a carcass there, and dirt was created; should I clean it, or could it have happened on his balcony as well, and it does not indicate that the cover is the cause of the dirt. I would appreciate Rabbi Fried's response.

Hello,

Of course, it is impossible to provide a complete answer without hearing both sides. The answer is only principled, according to the details of the question as presented by the inquirer. 

A. Blocking the view is a reason for initial objection but usually not for dismantling after it has already been done, especially such a blockage of view. B. Dirt does not need to be cleaned; it is a matter between a person and his fellow.