This article examines the architectural evolution of informal internally displaced person (IDP)
shelters within flood-prone areas of Nigeria by providing a typological analysis of how these
structures transform from emergency responses into semi-permanent settlements. By focusing on
case studies from Borno State and the Niger Delta, the research investigates how displaced
populations adapt their living spaces to handle recurrent flooding, material shortages, and the
reality of long-term displacement. The analysis identifies three distinct phases of shelter evolution:
the initial emergency stage using tarpaulin, an incremental upgrading phase utilising local
materials like bamboo and mud brick, and the eventual emergence of vernacular flood resilient
designs such as elevated structures. These findings suggest that shelter transformation follows
predictable patterns driven by environmental stress, a lack of infrastructure, and the extended
duration of displacement. The research demonstrates that displaced individuals are not merely
passive recipients of aid but active participants who innovate in the face of environmental
pressures. In areas frequently hit by rising water, the development of stilt-like supports and
moisture-resistant walling shows a sophisticated understanding of local conditions. This
typological framework provides humanitarian workers and policymakers with evidence-based
insights to move away from generic aid and toward context-appropriate interventions. By
balancing immediate lifesaving needs with long-term resilience, these insights help in supporting
shelter strategies that are better suited for the unique challenges of Nigerian flood-prone
environments.