Aerial photos taken after hurricanes have given researchers a new way to measure wind damage, and the results show that stronger building codes have made a real difference for Florida homeowners.
A collaborative team from Kyoto University and Kobe University developed a method to identify wind damage by scanning high-resolution drone and satellite images for blue tarps, the temporary sheeting homeowners use to cover damaged roofs. The research is published in the American Economic Journal: Economic Policy, according to a report by Phys.org.
The researchers applied their method to Hurricane Irma, which struck Florida in September 2017. They looked at data covering more than 1 million homes across eight South Florida counties and used tarp size as a measure of how severe the damage was. They also cross-checked their findings with building-permit records.
The study focused on Florida's 2001 Florida Building Code, known as the 2001 FBC. The code required new and reroofed homes to use stronger roof-to-wall connections, thicker roof decking, and impact-resistant windows and doors in certain areas. To measure its effect, the team used a regression discontinuity design, comparing homes built just before the code took effect with those built just after.
The gap was significant. Homes built under the new code were about 22% less likely to suffer wind damage. When damage did occur, its severity was roughly 27% lower than in homes built before the code.
The cost question had long been part of the debate over stricter building requirements. Many homeowners had to spend thousands of dollars to reinforce roofs or install impact-resistant features, with the average cost running about $4,930. Whether those investments paid off had not been clearly established before this study.
The financial consequences of damage extended beyond repair costs. Damaged homes that were sold before being repaired were harder to sell and, when they did sell, went for around 13.3%, or about $29,400, less than undamaged homes nearby.
The backdrop for the research is a broader shift in hurricane frequency and intensity. Storms like Hurricane Katrina in 2005, which caused more than $100 billion in damage, were once considered rare lifetime events. Climate change has made large storms more frequent, more intense, and slower-moving, deepening their impact. After Hurricane Ian in 2022, 44% of insurance claims were for flooding and 56% were for wind damage, yet most economic research has focused on flooding because wind damage is harder to map at scale.
Unlike flooding, there is no large-scale barrier that can shield an entire community from wind. Protection depends almost entirely on individual homes. That is what makes the building code question so central: if stronger codes work, they represent one of the few available tools for reducing wind damage across a wide area.
"This study provides large-scale evidence that stronger building codes are effective for reducing wind risk and adapting to climate change," said a co-author of the study.
The aerial imagery method the team developed could be applied to future storms, making it possible to track wind damage across hundreds of square miles after a hurricane makes landfall.
