Indexing resilience can help protect buildings against climate disasters

With the growing frequency and intensity of natural disasters, the need for building resilience is increasingly apparent. WBEF brought together experts at a recent webinar to offer insight on resilience and discuss a tool developed to increase the property market’s awareness of the concept.

The past 20 years have witnessed increasingly frequent and severe natural disasters, exacerbated by climate change and growing populations, according to the UN Office for Disaster Risk Reduction. Developing countries, with their geographic vulnerabilities, are particularly at risk of catastrophic events such as floods, storms and earthquakes.

Enhancing building resilience is therefore crucial to minimising the effects of these disasters. In a recent webinar, a panel of experts looked at how to ensure this, focusing in particular on the Building Resilience Index (BRI), a hazard mitigation rating tool developed to raise awareness and improve understanding in the property market.

Need to understand context prompts development of BRI

Resilience can be described as the capacity of an asset to withstand adverse conditions and its ability to recover quickly, explains Mattia Donato, associate director and head of bioclimatic design and climate adaptation at design engineering consultancy AKT II. He says that, as a society, ‘we’ve been designing buildings and infrastructure based on historical weather patterns. But with a changing climate we also need a changing built environment that can adapt and be resilient to future events.’

Traditionally we have built the same way regardless of location, says Aris Papadopoulos, founding chair of the Resilience Action Fund and distinguished expert in resilience at Florida International University. An identical building could be resilient in one location but very vulnerable in another, he says; the more prone an area is to natural hazards, the higher the cost of making it resilient.

As populations grow we are expanding into hazard-prone areas, explains Dr Tina Thomson, a regional director at reinsurance broker Gallagher Re. Such areas include the wildland–urban interface, which is at greater risk of catastrophic wildfires, and coastal zones, which are at risk of storm surges, tsunamis, hurricanes and windstorms.

Climate change is altering the conditions for and the severity and frequency of weather-related perils, such as hurricanes, droughts and floods, she notes. For example, drought conditions combined with the Santa Ana winds have been a key contributor to the recent wildfires in California.

Aris adds: ‘If we can't measure something, it's very hard to encourage and reward it, and measuring resilience has been a key challenge for many years.’ The BRI was therefore developed by the International Finance Corporation (IFC) for all sizes and types of building, to assess the mitigation measures they have in place for their respective locations.

The index is a rating rather than a certification, and requires on-site verification by IFC-trained building professionals. It was launched in the Philippines and is now also used in Vietnam, India, southern Africa, central America, the Caribbean and Colombia.

Design must be able to anticipate new hazards

When buildings are designed for hazard resilience, the focus tends to be on past experiences rather than future threats; but this leaves countries vulnerable to unexpected risks, says Mattia. He cites the example of Dubai, which has well-established mitigation measures to manage extreme heat but was overwhelmed by record rainfall and flash floods in April 2024.

Even in the UK, infrastructure can struggle with extreme rainfall that results in damage to buildings. He emphasises therefore that resilience must be a key consideration in meeting the government’s target of building 1.5m homes before the end of the current parliament. Similarly, although Canada is well prepared for cold-related hazards, he points out that it was affected by an unprecedented heatwave in 2021.

Limited attention has also been paid to the regulation of land use around buildings, says James Kavanagh MRICS, head of professional practice in land and resources at RICS and moderator of the webinar. ‘When we talk about government and stakeholders supporting efforts to make buildings more resilient, there is a need to think about the disconnect between building usage, resilience and land use,’ he says.

He explains that we should focus not just on the physical construction of homes but also the land on which they are sited. However, this is not always considered, with the result that, for example, homes can be built on flood-plains, in naturally occurring wildfire zones or other increasingly unsuitable locations.

In terms of climate change adaptation and mitigation we should prioritise passive design, says Mattia, which helps regulate temperatures through building orientation, windows and natural ventilation, among other measures. For example, we need to prevent overheating in new and existing assets and reduce reliance on cooling mechanisms so that energy use and cost are lower, he says. Incorporating low-carbon technologies and circular design principles in construction is another way to meet sustainability targets.

He also stresses the importance of avoiding a discrepancy between what we design and what we build, the so-called performance gap. For retrofitting, it is important to think about energy efficiency and durability, he adds, as energy-saving measures may lead to deterioration of existing assets.

Such deterioration can happen, for instance, when installing insulation creates delicate spots within walls or at junctions between roofs, windows and ground, increasing the risk of humidity, condensation or mould, or of freeze‒thaw damage. Meanwhile, installing additional shading elements to reduce cooling loads on glazing may lead to thermal shock, in particular where simple annealed glass is used.

Insurers should increase availability of cover

A country’s wealth plays a significant role in adopting resilience measures and securing insurance coverage. Wealthier nations have higher-value assets and therefore greater incentives to protect them, says Tina.

At the national level, GDP can be an indicator of how much governments may invest in comprehensive, high-level defence against hazards. But insurance availability and affordability remains a challenge, as demonstrated by the increasing protection gap not only in developing regions but in all places at high risk: it’s a gap that means insurers either won't cover high-risk areas, or price premiums so high that most people won't be able to afford them.

While catastrophe modelling allows insurance companies to assess and price risk more accurately and equitably, reducing the likelihood of abandoning high-risk areas, there is a much broader, complex interplay between government policies, climate change, human behaviour and finance and insurance.

The California Department of Insurance, for example, is updating regulation as part of its Sustainable Insurance Strategy to require that insurers increase their policy offerings in high-risk areas if they are planning to incorporate catastrophe modelling into their rate-setting process.

Tina suggests that risk mitigation must be much broader and more holistic than it is now, from prevention through increasing resilience to building back better, which insurers can promote by providing financial incentives such as premium discounts.

Filipino home offers rating case study

To consider how the BRI works, the panel looks at a two-storey residential building in the Philippines that was evaluated using the index for its resilience against such risks. The country is particularly vulnerable to multiple natural hazards, including typhoons, high winds, flash flooding, wildfires and earthquakes.

Located about 10km from the coast near Manila Bay and at an elevation of 100m, the site benefits from natural flood resilience as water flows away from the area. However, it is situated within 1.5km of a wildland zone, making wildfire risk a consideration.

The building is constructed with reinforced concrete, complies with earthquake standards such as ISO 3010:2017 and Eurocode 8, and is not built on filled land. Based on the BRI app assessment, the building is rated AA for wind, A for water, A for fire and AA for geo-seismic resilience, with an overall physical integrity rating of A. Ratings on the app run from AA to NR, with AA representing global best practices, A being strong practices, B minimal practices and NR weak practices or unpermitted.

The building does not achieve AA for water, however, as it meets only a 100-year storm-water retention standard, opposed to the 200-year capacity that the higher rating would require. If the building were redesigned, though, incremental storage could be added to satisfy this requirement. While the building has strong fire mitigation measures, its proximity to a wildland zone prevents it from achieving an AA fire rating.

In terms of operational continuity, the building has green certification and includes sump pumps and multiple accessible entries. Under the BRI system, buildings that meet at least three of ten specified criteria for operational continuity – which also include back-up off-grid power, water supply and communication links as well as having a post-disaster protocol and designated trained parties in place – have a plus sign added to their rating. This house is therefore A+, meaning that it is considered highly resilient and an attractive option for lending and insurance.

Aris highlights the importance of location in determining resilience: if this building were closer to the water or in a flood-prone area, significant additional expenditure would be needed to maintain its resilience, without which its rating would likely drop to a B.

Transparency about resilience enables sustainable market

Aris also emphasises the importance of transparency about a building’s resilience so potential buyers are better informed. He notes that lenders such as the IFC have already started considering resilience factors and insurability when approving loans.

Greater awareness and stricter lending criteria will lead to more resilient buildings, he believes. ‘For a building to be truly sustainable, it has to be both green and resilient,’ he concludes.

How can we improve building resilience in the face of increasing climate risks? This webinar explores innovative approaches to designing, constructing, retrofitting, and financing buildings to enhance resilience.

Featuring a presentation on the IFC’s Building Resilience Index a web-based tool that helps assess risks and improve transparency. This session also shares real-world case studies and key lessons from successful IFC resilience projects.