Strata bunny – you have mentioned that it is a “common property (water membrane) repair” in your subject line but then also mention that “carpet in bedroom ( associated with bathroom wall ) is now rotting / mouldy / smelly”.
In NSW the OC is only responsible for the waterproofing membrane on the floor or common property wall (i.e. the wall adjoining another lot or common property area). It is not responsible for the waterproofing membrane on internal walls of your lot. Our OC has had a similar request for repairs from a lot owner and the OC asked the Land and Property Information (LPI) Strata Team for clarification:
Q1: What is your definition of a shower recess which is located on and internal wall? It is obvious that the floor and the tiles attached to the floor are common property but how far up the internal wall is classified as common property.
A1: Tiles on an internal wall are not common property.
Q2: Whose responsibility would it be to repair water leaking through tiles on an internal wall not affecting any other lot?
A2: Leaking through an internal wall not affecting another lot is the responsibility of the lot owner.