Revealing (mis)alignments between household perceptions and engineering assessments of post-disaster housing safety in typhoons

Abstract

Building capacity for disaster risk reduction requires integrating local and scientific knowledge. We focus on local and scientific knowledge of the safety of housing in typhoons' wind, focusing on roof and wall systems. To identify alignments and misalignments between household and engineering understanding of safe housing, we conducted semi-structured interviews with 170 households that received new houses from organizations following Typhoon Yolanda in the Philippines. We qualitatively coded and analyzed these interviews to identify what housing components households expect to fail first, their preferred failure, and how they plan to modify their house to be safer in typhoons. We compared these responses to three results from engineering assessments: the governing failure mode, the failure mode that best meets safety performance objectives, and the quantified impact of design modifications. Household perceptions and engineering assessments were well-aligned when focusing on the damage expected to a single component and how to improve the performance of a single component. However, perceptions and assessments were misaligned at the housing level as households did not consider how housing components worked together as a system to influence performance. Households often did not recognize that modifying one component, such as the roof, would have an adverse impact on the performance of other components, such as the wall. This study is one of the first to systematically compare perceptions and assessments of housing safety and advances understanding of alignment, or misalignment, of local and scientific knowledge of safe building practices. We recommend that future post-disaster training programs incorporate discussions of a house's load path to focus on how components work together, enabling design and modification decisions that support improved housing performance.