Yes your interpretation is pretty much spot on. Requires a by-law for alteration or attachment to common property (in this case the floor and possibly common walls), which to pass requires a special resolution at a general meeting. As an owner I’d be concerned to see the plans before I’d even consider giving my blessing to it, even though that may not be a requirement under the Strata Schemes Management Act. I’d also say that even if the motion did succeed the Local Council may need to be involved.