The difference between strata and company title of course is that under company title the company, eg XYZ Pty Ltd, owns the building and you then hold shares in the company and that gives you a right of occupancy to a particular area (flat No 2 for example). There is no concept of ”common property” under corporations law as far as I am aware. I certainly wouldn’t be engaging architects, engineers and lawyers unless I had everyone well and truly onside first.