According to the latest laws and regulations in Shanghai, the newly added corridors should follow the principle of entering the house nearby and control the corridor span and cornice size. In principle, the clear width shall not exceed 1.2m, and the clear length shall not exceed1.5m. At the same time, the waiting hall and corridor shall be kept clear. The newly added corridor can only extend to the first bay adjacent to the original staircase, and meet the relevant requirements of the fire protection code. The natural ventilation, lighting and fire evacuation functions of the original stairwell should be retained. If it cannot be met, remedial measures should be added. New waiting halls and corridors are public spaces, and it is strictly forbidden to add, rebuild or expand the use area of residential units. It is strictly forbidden to install the entrance door, and turn the waiting hall and corridor into the exclusive space of the owner.