During the redesign of a dilapidated residential building located in a heritage-protected area, we created three residential units by demolishing and converting the high-rise roof. The extension below ground level ensures a more rational car arrival, while the terrace connected to the basement fitness room completely revalues the atmosphere of the basement room. The challenges of the project, the adaptation to existing structures, and the joint cooperation with the client are a good example of how it is not always necessary to build a new one, and the conversion of the existing one can also be effective and significantly reduce the environmental impact.