The theme of this issue is “living in the heart of the city”, the value enhancement of existing commercial and office buildings by changing their use to residential.
Recently, I had lived in Kuala Lumpur, the capital of Malaysia, where I spent my daily life. In Japan, it is an image of urban living in the Roppongi Hills area in Japan. There, I lived in a compact city where I could not only work, but also live within walking distance of shopping malls, restaurants, bars, iconic towers, city parks, and other attractive lifestyle amenities, and where I could easily get to know the Japanese community living nearby. I enjoyed a fascinating lifestyle that I had never experienced in Japan before. From this perspective, I would like to propose the creation of spaces that are effective in solving Japan’s urban issues.
In Japan’s major cities, conventional large-scale redevelopment is taking place, and the high vacancy rate of existing commercial and office buildings and the global environmental impact caused by the scrap-and-build approach are becoming social issues.
On the other hand, the number of cases and government support to promote the use of existing stock with consideration for reducing environmental impact, initial investment, and construction period continue to increase.
Therefore, we will introduce a concept that combines the above, an architectural approach to “change the use of commercial and office buildings in the city centre to live in the city centre.
Skeleton to be reused, infill to be updated
When changing the use of office commercial buildings to residential buildings through renovation, an effective method is skeleton-infill (SI), in which necessary functions are updated promptly on the premise that the existing structure is used as much as possible. Skeleton is the main structural component of columns, beams, floors, walls, and roofs, while infill is the interior space. This architectural approach is also common to new construction planning, including rebuilding needs after several decades.

Skeleton portion of the building utilizes the building’s external form, such as the main structural components and exterior walls, due to the high environmental costs of building regulations and waste disposal from the demolition of the building. In this process, seismic diagnosis and seismic repairs are updated to the latest conditions to increase the value of the building.
Infill portion will be removed except for those that can be reused, and content and applications that can appeal to an urban living will be incorporated as needed for the change of use. In this process, mechanical and electrical equipment, maintenance management, owner/user support systems, Web 3.0, etc. will be incorporated into the building program, and the value of the building will be increased as a system that can be updated to meet the needs of the times.
Spatial Branding Strategy
A change in architectural use can build a highly unique brand through functions, planning, and spatial organization that are different from traditional building types.
Examples of urban residential lifestyles include:
For low-income groups: dormitories, care homes
For middle-income earners: shared houses and condominiums with luxurious common spaces
For the affluent class: luxury urban residences such as villas and mansions that can be privately owned.
Matching functions and marketing methods using Airbnb (ABNB) and SNS for overseas users will be incorporated in all cases.
Living in the heart of the city to solve corporate social issues
Developments that enable attractive urban living are an opportunity to solve social issues such as population decline, declining birth rate, ageing population, and globalization. In particular, the change of use of existing real estate can promote compact cities to realize a sustainable decarbonized society by utilizing the resources of existing cities, including not only the problem of vacant buildings brought about by large-scale redevelopment, but also vacant houses, vacant land, and mobility issues in the suburbs. Not only is this a method that fits the times as a method for solving social issues, but it is also attracting attention as new architectural content for improving inter-city competitiveness in terms of location, convenience, spatiality, globalization, and regionalization.