This is a renovation of a three-story steel-framed house. The existing floor plan, materials, and facilities were preserved as much as possible, and the house was re-tailored to suit current and future lifestyles. The living room is located on the sunny second floor. It is a large room that mixes Western and Japanese styles, and is connected to the kitchen and washroom to expand usability and storage capacity. The first floor is designed as a calm space by reorganizing the bedroom, workspace, and closet, while the compact sanitary and kitchen can be used to live as a one-story house in the future. Both floors are designed to be a comfortable home for the cat and his owner.