Typically, older Australian houses built prior to the mid-1980s do not offer the same level of performance and protection during severe wind as houses constructed to contemporary building standards. Given that these existing older houses will represent the bulk of the housing stock for many decades, practical structural upgrading solutions based on the latest research will make a significant improvement to housing performance during storms, and to the economic and social well-being of the community.

This project is developing the evidence base for risk mitigation by devising simple practical and economic upgrading options for existing houses. The outcomes will promote retrofit investment by home owners and provide a basis for incentives to encourage this action through insurance and government initiatives.

The primary objective is to develop cost-effective strategies for mitigating damage to housing from severe windstorms across Australia. Outputs from this project will target a range of end users, from policy development through to homeowners and builders on recommended actions to improve resilience of existing housing. The uptake of the research will reduce the cost of natural disasters in Australia.

The project has collected and analysed information from the impacts of tropical cyclones and thunderstorms, which will provide valuable input into the development of vulnerability modelling. It has published reports on recent events including the 2014 Brisbane thunderstorm, 2015 tropical cyclones Nathan, Marcia and Olwyn, and 2017’s Cyclone Debbie.

Storms outside of the tropics are also part of the study, with the team conducting surveys in Adelaide and Canberra. The geometry of houses in south east Australia is the least understood, and to address this the team undertook a desktop examination using aerial imagery and Google Street View of 467 houses in Canberra to determine the most common geometries from houses constructed in the 1960s.

The team has also collaborated with the insurance company Suncorp to analyse 25,000 insurance claims from cyclones Larry (2006) and Yasi (2011), with the purpose of gaining a better understanding of the drivers of cyclone damage.

The project will categorise residential structures into types based on building features that influence windstorm vulnerability using Geoscience Australia and Cyclone Testing Station survey data. From these a suite will be selected to represent those contributing most to windstorm risk.

The project has engaged heavily with key stakeholders and will continue to involve end-users and stakeholders (homeowners, builders, regulators, insurers) to assess amendments and provide feedback on practicality, cost-effectiveness and aesthetics of potential upgrading methods for a range of buildings. A webinar series has also been piloted, allowing home owners to understand the importance of making appropriate decisions at various stages of the building process, and providing information on various aspects of building to resist wind loads for builders, certifiers and designers to become aware of issues that have caused failures previously.

Vulnerability models will be developed for each retrofit strategy using survey data, the authors’ existing vulnerability models, and the NEXIS database of Australian housing characteristics. Case studies will be used to evaluate effectiveness of proposed retrofit solutions in risk reduction. Economic assessment using these case studies will be used to promote uptake of practical retrofit options.