Amphibious Buildings as a Response to Increased Flood Risk: European Case Study

As reported in the most recent IPCC report (2022), the risk of flooding in Europe has increased over the last five decades, becoming the second largest cause of both economic and social losses caused by climate change-induced extreme events. Nowadays, the adaptation of vulnerable urban areas has become a priority objective in the political and legislative management of cities. Among the different architectural measures to adapt the city to the negative externalities caused by the rise in the mean sea level is the design of amphibious buildings (AB) to reduce the vulnerability of private space in the city. ABs are buildings composed of a structure that allows flotation while remaining anchored to the point of origin on land. During floods, the floating foundation of ABs allows it to rise from the ground and float on the surface of floodwater. Although several AB prototypes are nowadays built both in North America and Asia, only four projects have already been built in Europe. The aim of the article is to collect, catalog and describe the characteristics of ABs as a response to urban flood risk. Methodologically, the architectural qualities of ABs are researched by comparing, through a matrix, the four constructed European cases. Then, the architectural qualities are investigated in a SWOT matrix analysis. Indeed, through a review of the existing cases, with a focus on data related to the construction and implementation of ABs in the urban fabric, results are presented on the parameters of safety, purpose, aesthetics, technology, sustainability, utility, and cost-efficiency. We consider that through the orderly classification and cataloging of the state of the art of built AB buildings, it is possible to define new paths for architectural and urban implementation in order to respond to the need for urban adaptation to extreme water events.