An innovative housing design strategy for flood adaptation: conceptual development and numerical validation of a novel piston house system for Japanese wooden architecture

Flood hazards intensified by climate change increasingly threaten residential areas in flood-prone regions, particularly where wooden architecture is common, such as in Japan. While these houses hold architectural and cultural significance and demonstrate seismic resilience, they remain highly vulnerable to inundation. This study presents a climate-driven flood coexistence strategy through the development and validation of an innovative solution, the piston house system, tailored for Japanese wooden houses. The system enables only the floor to rise vertically within the structural frame in response to floodwater, preserving the integrity of the main structure. Compared to conventional floating house technologies, this design minimizes lateral instability, reduces buoyant force requirements, and maintains both architectural aesthetics and residents’ daily lifestyle patterns. To support this strategy, the study begins with a review of global flood-adaptive housing typologies and assesses their applicability to Japan’s socio-architectural context. The piston house concept is then refined through targeted component design and validated via simplified numerical simulations, examining key performance criteria such as buoyancy capacity, vertical displacement stability, and load transfer through guiding rail systems. Results show that standard underfloor spaces in typical Japanese wooden homes can house sufficient buoyant material and that existing commercial rail components can provide effective vertical control under flood conditions. These findings confirm the technical feasibility and cultural compatibility of the piston house as a scalable, low-impact retrofitting solution. It offers strong potential for application in regions with similar housing typologies and aging populations, supporting long-term resilience and sustainable coexistence with climate-induced flooding.