HYAN's 'Green Sandwich House': A Modern Renovation Embracing Heritage in Hayama



























In a compelling display of architectural ingenuity, Japanese firm HYAN has reimagined an aging 1970s timber residence in Hayama, Kanagawa, transforming it into a contemporary dwelling and workspace for its principals. This extensive renovation, completed in 2025, stands as a testament to the studio's commitment to sustainability and respect for architectural heritage, as it consciously opted to preserve and upgrade the existing structure rather than undertake a complete demolition and rebuild. The project artfully blends the nostalgic charm of the original construction with modern design principles, creating a living and working environment that is both functional and aesthetically pleasing, while also meeting current seismic safety standards.
The original house, constructed in the late 1970s, predated Japan's stringent 1981 seismic codes. Located in a hillside residential area behind Hayama's historic imperial villa district, the property offered a unique opportunity for HYAN to integrate their design philosophy into a structure with a rich past. Rather than simply imposing new elements, the renovation focused on a thoughtful reinterpretation of the existing spatial layout and material palette. The architects meticulously reinforced the building's structural integrity, ensuring it could withstand future seismic events, while simultaneously enhancing its aesthetic appeal and functionality.
The renovation strategy embraced the concept of 'inheritance,' wherein the spirit of the old house was maintained while being adapted for modern living. This involved a careful selection of materials, with a particular emphasis on wood, which not only resonated with the original timber construction but also contributed to a warm and inviting atmosphere throughout the interiors. New elements were introduced with a keen eye for continuity, ensuring that additions complemented the existing framework rather than clashing with it. This approach allowed for the creation of open, light-filled spaces that foster creativity and tranquility, perfectly suited for a combined home and studio.
The updated residence now boasts a harmonious blend of private and communal areas, designed to facilitate both domestic life and professional work. Interior spaces feature clean lines and a minimalist aesthetic, punctuated by natural light and the textures of wood and other organic materials. The project exemplifies how older buildings can be revitalized to serve contemporary needs, proving that sustainable architecture often involves thoughtful renovation rather than outright replacement. By choosing to 'inherit' and adapt, HYAN has created a unique property that respects its past while firmly embracing the future of design and living.
The transformation of the Hayama house into the 'Green Sandwich House' underscores a broader trend in architecture towards adaptive reuse and responsible development. This project by HYAN demonstrates that renovating existing structures can yield aesthetically sophisticated, highly functional, and environmentally conscious results, all while honoring the historical context of the site.