I have been lobbying for many years for building standards and development consents to include a load rating for balconies and deck and for mandatory display of the maximum loading, similar to what is shown inside elevators, on a label near the entry onto the balcony or deck.
This is due to collapse of some balconies and decks which has resulted in serious injury and death. This has been due to excessive loads and lack of inspection and maintenance.
I recommend that you have your balcony or deck checked and carry out necessary maintenance such as replacing corroded fasteners and fittings, installing additional fasteners or supports, replacing damaged framing.
I also recommend that you engage an Engineer to provide a maximum load rating for you balcony or deck. Better to be safe than sorry.
N R Wallace Building Inspections can carry out a thorough inspection and provide recommendations to ensure that the structure is safe.