Urban and Bushfire Protection

The role green roofs, walls, and facades play in fire-resilient cities

By Michael Casey

As climate change intensifies, bushfires are becoming more frequent and severe, posing significant threats to homes, communities, and ecosystems in fire-prone areas worldwide. The recent fires throughout Los Angeles are an example of how ferocious these fires can be both in a built-up urban area, and in the buildings and houses located in the more naturalised areas surrounded by trees and plant life. As a country shaped by fire, Australians need only look back to the Black Summer of 2019/20, when devastating fires swept through Victoria and NSW. Fires in bushland or urban environments pose significant risks to the built environment. This article explores how green roofs, walls and facades may bolster fire resilience, drawing on global examples, and including recommendations in Australia’s bushfire-prone regions.

Without proactive interventions, these challenges will only worsen in the future.

Traditional construction methods often struggle to withstand extreme conditions like fire, necessitating innovative solutions to improve resilience. It is crucial to develop strategies to protect properties in rural and urban areas from such risks. Engineered green infrastructure, such as green roofs, walls and facades, known for their environmental benefits, may emerge as a vital solution in mitigating fire risks. By combining sustainable design with fire-resistant vegetation and materials, green roofs, walls and facades not only protect structures but also support biodiversity, reduce urban heat, and improve air quality.

Green roofs, walls, and facades are innovative green infrastructure solutions that integrate vegetation into building designs. Green roofs consist of plant layers atop buildings, offering insulation and ecological benefits. Green walls, including living walls and vertical gardens, are panels of plants grown vertically, supported by irrigation systems. Green facades use climbing plants to cover building exteriors. Could integrating fire-resistant green infrastructure into building designs not only protect homes from fires but also transform fire-prone areas into sustainable, resilient communities?

Green infrastructure enhances fire resilience by leveraging vegetation and innovative design to protect buildings in fire-prone areas. Still, careful planning is required to ensure they don’t also aid or promote a fire. Green roofs that retain moisture and use fire-resistant plants can form a barrier against embers. In contrast, green walls incorporate fire-retardant plants and irrigation systems to reduce ignition risks on vertical surfaces. Green facades employ climbing plants to shield exteriors, lower surface temperatures, and disrupt wind-driven flames. These systems collectively reduce combustible surfaces, insulate buildings, and integrate with fire-safe landscaping for comprehensive protection. By combining fire resistance with environmental benefits, green infrastructure offers a sustainable solution for safeguarding homes and communities.

In Australia, installation companies are now prioritising fire resistance with their products, especially for roofing, wall, and facade materials. The industry and regulators now require rigorous fire testing to ensure materials are as fire-resistant as possible. Certification can assist with compliance since no specific standards exist for green infrastructure materials. Companies must demonstrate that plastics and other flammable materials used in these solutions have low combustibility and meet strict fire safety standards. While companies in North America, Southeast Asia, and Europe have obtained compliance, their testing results do not always apply in Australia, but they still help with achieving relevant certifications

As mentioned earlier, suburbs are expanding into rural and regional areas, with houses being built closer to bushland, raising challenges for planning and design. Recently, I have encountered a growing interest in green roofs for new buildings in rural areas to improve the house’s R-value. The R-value is a measure of thermal resistance, indicating how well a material prevents heat transfer in or out of a structure. The questions posed in these initial consultations have been based on the building and planning approval for the inclusion of green roofs onto a new dwelling. Currently, in Victoria, it’s a grey area with the Country Fire Authority (CFA Victoria) stating in their Landscaping for Bushfire Guidelines document that suitable landscapes for fire-prone areas, or areas that reside in a bushfire overlay, are to abide by strict guidelines on the use of vegetation up to and on dwellings. The document states that there must be clearance around all buildings and that no build-up of flammable materials is to be on the sides of the dwelling or on the roof. These recommendations were also similar in NSW and QLD documents and guidelines.

On the international scene, the Department of Communities and Local Government in the UK have a detailed document on ‘Fire performance of Green roofs and Walls’ that summarises and documents the risks associated with fires on green roofs and walls, and details the design elements that must be adhered to when specifying these projects. Recently, I attended a talk in the Netherlands on fire safety for urban greening, and their take on this topic was that all projects must comply with city fire safety rules, and that the risk of wildfires in the urban environment is a real threat. Their approach to their design and planning of urban greening is to ensure there’s accessibility for fire services and the fire can be reached, that there are escape and evacuation options, and that water is available to put these fires out. With many other countries expressing concern over the safety of these greening installations, it’s important to know that they are still encouraged as long as multi-layered safety measures have been implemented.

In addition to fire resistance in building materials, studies have been conducted on suitable plant selections for green roofs, walls, and facades. Companies, including mine, have been evaluating plant choices and their suitability across various capital cities to determine the best options for these green infrastructure solutions. Even though these projects were located in city environments, they still posed external threats such as electrical components that could start fires, residents using the gardens as places to extinguish their cigarettes.  and other everyday hazards that can cause house and structural fires. These are all risks that could lead to catastrophic fires. All companies I’ve engaged with over the years emphasise that professionals must carefully plan green infrastructure solutions. Beyond aesthetics, considerations must address the flammability of materials, plant choices and other potential fire risks. Thorough evaluation and design strategies are essential to manage these aspects effectively.

While addressing the flammability characteristics of green roofs, walls, and facades is essential, it’s equally important to recognise that organic materials like bark, coir, and other substrates can increase fire risks by fuelling existing fires. Moist growing media and fire-resistant plant species help reduce combustibility, whereas dry substrates heighten fire hazards. Irrigation systems should be designed to nourish plants and serve as firefighting measures when necessary. Proper maintenance, including moisture management and removal of dry vegetation, can significantly reduce fire risks. When maintained by professionals, green roofs demonstrate better fire performance than traditional roofs. These findings highlight the need for appropriate materials and ongoing maintenance to enhance fire resilience, aligning with sustainable urban design practices in fire-prone areas. Always consult a professional green infrastructure expert and reference fire regulations when planning such projects.

Green roofs, walls, and facades provide an innovative, sustainable solution for enhancing fire resilience in fire-prone areas. By incorporating fire-resistant vegetation, moisture-retentive substrates, and careful maintenance, these systems reduce fire risks while delivering environmental benefits like improved insulation and biodiversity. They represent a vital shift toward safer, more sustainable urban design, offering communities a proactive way to adapt to increasing building fires, bushfire threats and climate change. Embracing green infrastructure is key to creating resilient, eco-friendly, and future-ready environments.

Michael Casey

Director of Evergreen Infrastructure,

Company Director at the Australasian Green Infrastructure Network

Advisor, Technical Panel for the AIPH World Green Cities Awards

E: michael@evergreeninfrastructure.com.au