It may seem like a “clear-cut case” but few if any issues in strata are clear-cut. All you have to do is prove there is a fault or defect in common property, then prove that flaw is causing water leaks, then prove the water leaks are causing the damp, then prove the damp is causing the mould, then prove the mould is harming your health. Attack-dog lawyers might make you jump through all those hoops to deter you and anyone else from exercising your rights.