It probably isn't much more expensive to just build a new building on an empty lot or other easy to demolish land if you can. You need to spend a lot of money t

It probably isn't much more expensive to just build a new building on an empty lot or other easy to demolish land if you can. You need to spend a lot of money to buy the existing building/land, basically gut everything inside until it's just a concrete shell and then rebuild everything into a residential design (electricity, plumbing, insulation, elevators, garbage disposals, amenities, windows, etc.). Then you probably still get apartments that are worse in design than a purpose built building so won't be worth as much.