Speeding up post-disaster reconstruction: material choice or roof design?

The consequences of urbanization and climate change are dangerously converging. The most affected populations are the urban poor, settled in informal settlements, vulnerable to increasingly frequent disasters. This severely contributes to the existing housing gap of the affected regions, already struggling with housing demand. The speed of shelter delivery becomes key for an efficient response. The present study aims to understand the impact of material choice on postdisaster shelters delivery through a multiscale analysis of their construction speed. The scales considered for the study are: Constructive technology, Shelter Unit and Post-disaster settlement. At the scale of the Constructive technology, nine different solutions suitable for the Nepal earthquake reconstruction are compared, covering a range from local to industrialized. Successively, twelve different shelter designs delivered worldwide by the International Federation of the Red Cross have been studied under the same lens, at the Shelter unit scale as well as for the case of the Post-disaster camp. The study shows that a clear correlation between material procurement and speed can be identified at the element scale. This correlation becomes secondary at the shelter scale, where it is visible that materials play a limited role in affecting the construction time, that is mainly driven by the complexity of the roof design. Moving to the settlement scale, the procurement choice of materials seems to be impacting the speed again. The study indicates how no univocal solution fits for the three different scales of the study, providing efficient guidelines for post-disaster reconstruction. Beyond that, it highlights that effective construction can be developed with a variety of materials, but its emergency responsiveness can seriously be compromised by a non-appropriate design.