Perennial pluvial flooding presents significant challenges to the urban environment of Port Harcourt Metropolis, impacting infrastructure, public health, and overall urban functionality. This research investigates architectural adaptation strategies aimed at mitigating the negative effects of recurrent flooding, focusing on the impact of perennial pluvial flooding on residential buildings in Port Harcourt Metropolis, with the intent on identifying vulnerable areas, assessing the impact of perennial pluvial flooding on building performance, and evaluating existing mitigation measures. Blue-Green Infrastructure (BGI) Theory and Resilience Theory guided the theoretical framework of this study. The methodology integrated both primary and secondary data sources. With a population of 1,416, a sample frame of 708, and a sample size of 512 determined using the Taro Yamane method, the study employed field observations, surveys, and statistical analysis, including descriptive statistics. Additionally, Geographic Information Systems (GIS) were used to identify flood-prone areas within the metropolis. The findings highlight highly vulnerable areas, such as Rumuewhara New Layout/Eneka (elevation 17.1m) and NTA/Apara Link Road (elevation 13.5m), where floodwaters can reach depths of up to 200mm. Over 90% of respondents identified streets in Obio/Akpor Local Government Area (LGA) as the most affected in the metropolis. Moderately and low-flooded areas display community-driven mitigation efforts, such as flood barriers, but government strategies are found to be lacking. The findings also revealed that flooding negatively impacts building safety, aesthetics, comfort, and durability, with 80% of respondents reporting moderate damage and 25% highlighting severe effects on structural integrity. The study recommends a comprehensive Flood Resilient Design Framework (FRDF) involving a multi-faceted approach to mitigate perennial pluvial floods in Port Harcourt Metropolis, including architectural adaptations, urban planning and policy changes, community engagement, and infrastructure development.