A 52-year-old wall-structure apartment building that had to be kept and used rather than demolished. Through a reversed idea—removing floors to create voids and thereby raise seismic performance—floor area was deliberately cut and turned into added value. Rooms left in their stripped state, which residents can customize by DIY, were also provided.
The Void-Retrofit Apartment Building
Data
- Completed
- 2025
- Primary Use
- Rental housing
- Project Type
- Renovation (rebuild + floor-area reduction)
- Structure / Scale
- Wall-structure reinforced concrete, 5 stories
- Site Area
- 392.03㎡
- Building Area
- 217.08㎡
- Total Floor Area
- 1,085.40㎡ before renovation / 498.39㎡ after
- Architects
- Takeshi Shikauchi + Masako Shikauchi
- Client
- Iseu Co., Ltd.
- Structural Design
- TTSE Inc.
- Contractor
- Ohara Construction Co., Ltd.
- Photography
- Kouichi Torimura / Kouichi Torimura Photography
A Renovation That Cuts Floor Area to Raise Value
A renovation of a 52-year-old RC wall-structure apartment building. Rather than being divided among unit owners, the whole building is held by a single owner, and the current owner, who inherited it from the previous generation, asked us not to demolish and rebuild but to keep and use it as it was, for the sake of the community. A single stop out from a terminal station on the periphery of the city center, such stock tends to have few tenants and becomes a source of worry for property owners. The turning point came in discussion with the structural engineer, who noted that “a wall structure can be made more seismically resistant by removing floors to create voids.” Reducing floor area lowers rental income—the very opposite of real-estate logic—yet we chose to deliberately cut floors to make voids and turn this into added value. Within a limited budget, we prepared living spaces with a degree of insulation secured, and the places left in their stripped state we named “customize rooms,” which tenants are free to use and to DIY as they like. Perhaps because a rawness remains, it is a curious space—indoors, yet as if one were out in nature—and the excessive sense of scale of a three-story void may be what produces that feeling. With these customize rooms, we feel that the residents’ lives, their pleasures, and their involvements within daily life will keep expanding.
