Is my rooftop terrace common property or entirely my responsibilty?

Hello everyone.

I live in a warehouse apartment such that all the units, including my own, have three stories which are ‘vertically self-contained’, i.e. although we have common walls, no other unit is under or over any other unit.

The flat roof of my unit is a tiled terrace which is for my use only. Directly underneath that terrace is my living room. The deck is leaking (a problem with the tanking/membrane I’m informed) and water is dripping into my living room via the ceiling.

Although common sense would tell me that this is (or should be!) entirely my responsibility to repair (my terrace, my living room), I don’t want to foot the bill if my terrace is common property and therefore, I assume/hope, covered by the building insurance taken out by the owners’ corporation.

The strata was registered post 1974 and I live in Victoria.

Is my rooftop terrace in fact common property?

Any help would be greatly appreciated!