michele – the first issue to resolve is a possible breach of a generic Strata By-Law that states:
“An Owner of a Lot must ensure that all floor space within the Lot is covered or otherwise treated to an extent sufficient to prevent the transmission from the floor space of noise likely to disturb the peaceful enjoyment of the Owner or occupier of another Lot.”
The second issue is that as the floor structure of one Lot is the ceiling of the one below, that area isn’t the sole property of any individual Lot Owner and is instead the Common Property of the Owners Corporation (O/C) as a collective of all Lot Owners.
So if by your use of the term “replaced” you mean taking-up the floorboards and installing a different material, then in the absence of “special” By-Law that’s been Registered on the Title of your specific Strata Plan and which sets-out how such an activity by Owners may be undertaken, then any activity that involves a physical change to the structure of the floor cannot be undertaken without a whole lot of rigmarole that culminates with General Meeting of the O/C voting upon whether or not those works may be consented, and under what conditions.
There are some navigable ways forward, but in order to narrow those down a little, can you advise if both you and your upstairs neighbour are Owners?