Chimney work fall under communal repairs?

akira181

With this bad bout of weather we've been having, a significant amount of water has been coming in through the fireplace. I believe either the flashing has a leak or the crown coat has developed a crack.

I live in a 3 story terraced house and I'm on the ground floor, so I'm probably bearing the brunt of the leaking chimney. If I go ahead and get repairs to the chimney done, can I request the bill to be split 3 ways?

I know whenever we do have communal repairs, like the roof, the guy in the top floor flat always demands that one particular builder does the work. I know for a fact that they are mates and he is a terrible builder. Can I just get three quotes, choose the best quote, and then split the bill 3 ways without his consent on the builder we use?