Well the first thing you need is a motion that has been voted down proposing a special levy to pay for the repairs or a motion that voted against repairing the damage. This needs to be voted on by the owners (because the EC doesn’t have the authority to approve this level of spending).
Then you lodge a conciliation request with NCAT if that fails you lodge a Adjudication against the OC. Cost to you about $150 for lodging fees.