Who is responsible for common area repair on association property?

I am on the board of a sixty unit condo association in Connecticut. In the past it was permitted for owners to have additions built in the area where there patio/deck would normally go. When this was done owners would hire thier own contractor. My question is since this is now a part of the structure and it was built way back in 2007 is the contractor liable for damages caused in construction? We have found water issues developing due to modifications of the original gutters. Is this ultimatley the associations responsibility or the responsibility of the contractor? How long would the contractor be responsible for the poor work if so?