I agree with Apartmentalize. That is exactly what I would do to, move out and let the water leak down into apartment below. I have lived on the top floor of an apartment complex (though it was no penthouse) and just as the roof space above me was not mine, neither was the roof that sheltered all of the units in the complex not just those on the top floor. I would have thought that was the case most of the time unless the roof was on title or in a special by law. If a roof leaks it could affect the structure of the building.