They mean the apartment building hallways and elevators. As in, if you summed the square footage of all the apartments on a floor, you'd get a number greater than the actual dimensions of the floor, because the common areas are counted multiple times.
They mean the apartment building hallways and elevators. As in, if you summed the square footage of all the apartments on a floor, you'd get a number greater than the actual dimensions of the floor, because the common areas are counted multiple times.