Flat Renovation in Sakurazaka by ICADA + Masaaki Iwamoto Laboratory

Redefining Flexible Living in Fukuoka’s Urban Apartments

Located in Fukuoka, Japan, the Flat Renovation in Sakurazaka designed by ICADA + Masaaki Iwamoto Laboratory reimagines the future of apartment living. This project transforms a 30-year-old, 86 m² flat into a highly adaptable home for a family of four, demonstrating how flexible design can support changing lifestyles across generations.

Concept: Living Spaces that Expand and Contract

Unlike the traditional Japanese apartment layout—compact, rigid, and designed for nuclear families—this renovation introduces a dynamic spatial system. The architect, Masaaki Iwamoto, designed his own family’s home to evolve over time. Recognizing that children grow, leave, and parents’ needs shift, the design rejects fixed rooms and instead offers flexible partitions that allow spaces to expand, merge, or separate.

At the heart of this idea are three movable bookcase partitions, functioning as walls for the bedrooms. These can be scattered to create four private alcoves or grouped together to form one large open room. When the polycarbonate sliding doors between the living and private areas are opened, the entire flat becomes one continuous space—perfect for family gatherings, events, or simply enjoying openness after children move out.

Materials: Everyday Urban Elements Reimagined

The renovation embraces practical, accessible materials and transforms them into refined architectural details:

• Movable bookcases – modified library shelving units repurposed as flexible partitions.
• Sliding doors – crafted from thick polycarbonate panels with corrugated metal rails, offering a modern reinterpretation of traditional Japanese shoji screens.
• Insulation panels – aluminum-foil-backed sheets typically used in factories now line the ceilings, improving thermal comfort while reflecting natural light deep into the interiors.

The result is a home that feels minimal, adaptable, and uniquely Japanese, while also showcasing inventive reuse of industrial materials.

Thermal Comfort and Light

Energy performance was a crucial focus. The design team added continuous insulation across the entire flat, including walls shared with neighbors—reducing heat transfer in the dense apartment block. Natural light is maximized through reflective aluminum-backed ceilings, creating brightness in all rooms without excessive artificial lighting.

Furniture as Architecture

Practical, multifunctional furniture is integrated into the design, blurring the boundary between interior design and architecture:

• A bench by the window, inspired by traditional Japanese tatami rooms, functions as a seat, clothes-folding station, and children’s play zone.
• A cantilevered rotating light, constructed from stainless steel square pipe with a lead counterweight, serves both the dining counter and the large worktable, adapting to family activities.

A Model for Future Urban Living

This renovation is more than a stylish update—it is a prototype for urban housing in Japan and beyond. By prioritizing flexibility, sustainability, and adaptability, the design ensures the home can grow with the family, rather than confining them to outdated spatial models.

In a city where most flats follow rigid layouts, the Flat Renovation in Sakurazaka sets an inspiring precedent for transformative apartment living.

All the photographs are works of Yurika Kono