20th-Century World Built Heritage Facing Water: Conservation of Fallingwater and Boa Nova Tea House

The conservation of 20th-century architectural heritage presents unique challenges due to the modern materials and construction techniques used by pioneering architects. This paper investigates the preservation challenges of iconic architectural works exposed to water environments, focusing on Fallingwater by Frank Lloyd Wright and the Boa Nova Tea House by Álvaro Siza Vieira. These structures, situated in natural settings with significant exposure to water, serve as case studies for examining conservation methods and their broader implications. This study explores archival documents, interviews with conservation experts, and literature reviews to highlight the main degradation phenomena related to the impact of environmental conditions on the material’s integrity. Despite limited specific data on monitoring and maintenance, this research underscores the importance of ongoing conservation efforts. Fallingwater’s case highlights the necessity of restoration techniques, while the Boa Nova Tea House illustrates minimal intervention strategies to maintain authenticity. This study concludes that the effective conservation of 20th-century built heritage necessitates a balance between preserving original design intents and adapting to environmental challenges. It emphasizes the need for innovative conservation strategies, adherence to international guidelines, and the establishment of comprehensive management and monitoring plans to safeguard the integrity and authenticity of culturally significant architecture.