The apartment building had undergone a capital renovation in the early 1970s, concrete floor were put in at all levels. As a result when we bought the apartment there were no antique elements left so we took the floors & ceilings back to the concrete & the walls back to the brick, removing all partition walls.  We rebuilt it with a different room layout,  moving the kitchen, adding an en-suite, removing a hallway & putting the bathroom back as a single room rather then their traditional separate toilet & bathroom. We also replaced the windows opting for wooden double glazing.  For us the project seems to be ongoing, there is always something to be changed here or there.