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The effects 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 these regions, already struggling with housing demand. The speed of shelter delivery becomes key for an efficient response in order to prevent spontaneous informal resettlements on unsafe lands. The present study aims to understand the impact of material choice on post-disaster shelters delivery through a multiscale analysis of construction speed. The scales considered are: Constructive technology, Shelter Unit and Post-disaster settlement. At the the Constructive technology scale, nine different reconstruction solutions for the Nepal earthquake are compared, covering a range from local to industrialized. Successively, twelve shelter designs by the International Federation of the Red Cross have been studied under the same lens at the Shelter unit scale and for Post-disaster settlements. The study identifies a clear correlation between material procurement and speed at the constructive technology scale. At the shelter scale, this correlation becomes secondary and construction time is seriously impacted by the complexity of roof design. Moving to the settlement scale, the choice of local over industrialized materials seems to drive the speed again. The study indicates how a multiscale approach is necessary to analyze the impacts of material selection, providing efficient guidelines for post-disaster reconstruction. Beyond that, it highlights that effective reconstruction can be developed with diverse materials, but its emergency responsiveness can seriously be compromised by a non-appropriate design.