I am happy to say iy=ts not as complex as the previous poster made out.
Firstly the OC is responsible to repair and maintain common property. If they dont clear the gutters its a clear breach of their duty
Similarly, if the waterproofing of the balcony was done by poor tradesmen, its the OC problem to either get it rectified by the contractor or do it again.
None of the above require any motions at meetings as its enshrined in the act.
I would , if you already have not, write to the strata manager telling them to clean the gutters and fix the waterproofing. Give them two months
Then threaten to take them to NCAT under section 232 , 1(f)
If that doesnt move them then apply to NCAT for orders to fix the waterproofing and clean the gutters.
Remember you will need some proof, say photos of flooding, invoices of rectification work you have paid for etc