Designing Homes for Bushfire Prone Areas in New Zealand
As climate change continues to reshape our environment, the risk of wildfires in New Zealand is increasing. This growing threat necessitates that homeowners, architects, and builders consider fire resilience as a critical component of home design, especially in bushfire-prone areas. This article explores the essential principles and strategies for designing homes that can withstand the challenges posed by wildfires, drawing on local research and expert recommendations.
Understanding the Bushfire Risk
Climate Change and Wildfire Frequency
New Zealand’s climate is becoming hotter and drier, leading to conditions that are more conducive to wildfires. According to Scion’s Rural Fire Research Team, climate change is predicted to increase the frequency, severity, and season length of fire weather conditions in many regions, particularly in Central Otago, Mackenzie Country, and Marlborough. The devastating fires at Pukaki and Lake Ōhau in 2020, which destroyed 48 houses and burned thousands of hectares, underscore the urgent need for fire-resilient home design.
Wildfire-Prone Areas
Identifying wildfire-prone areas is crucial for effective planning and design. The Port Hills wildfire in 2017 and the Lake Ōhau fire highlight the vulnerability of homes located in the rural-urban interface, where residential areas are adjacent to or intermixed with rural vegetation. These areas are particularly susceptible to wildfires due to the proximity to flammable natural materials.
Principles of Fire-Resilient Home Design
Non-Combustible Materials
Using non-combustible or fire-resistant materials is a fundamental strategy for enhancing the fire resilience of homes. Fire and Emergency New Zealand (FENZ) recommends materials such as:
- Roofing: Metal or concrete tiles that resist ignition from embers.
- Cladding: Non-combustible materials like brick, stone, or fibre cement.
- Windows: Double-glazed windows with toughened glass to withstand high temperatures.
Creating Defensible Space
A defensible space is a buffer zone around a home that reduces the risk of fire spreading to the structure. Key actions include:
- Clearing Vegetation: Removing flammable plants, dry grass, and dead leaves within 10 metres of the house.
- Pruning Trees: Ensuring tree branches are pruned to at least 2 metres above the ground to prevent ground fires from climbing.
- Maintaining Lawns: Keeping grass short and well-watered during the summer months.
Ember Protection
Embers are a leading cause of home losses during wildfires, as they can travel long distances and ignite flammable materials. To protect against embers:
- Install Metal Screens: Use metal mesh screens on vents and windows to prevent embers from entering the home.
- Clean Gutters: Regularly remove leaves and debris from gutters to prevent ignition.
- Enclose Decks: Ensure that the area under decks is enclosed to stop embers from accumulating and igniting flammable material.
Fire-Resistant Landscaping
Landscaping can play a significant role in protecting a home from wildfire. Consider the following:
- Fire-Resistant Plants: Use plants that have high moisture content and are less likely to ignite.
- Hardscaping: Incorporate non-flammable materials such as gravel, stone, or concrete in pathways and garden beds.
- Spacing: Maintain adequate spacing between plants to prevent fire from spreading quickly.
Water Supply and Access
Having a reliable water supply and ensuring easy access for emergency services are critical for fire protection:
- Water Tanks: Install water tanks with a dedicated firefighting outlet.
- Driveway Access: Ensure driveways are wide enough (at least 4 metres) to accommodate fire trucks and that there are no overhanging branches or obstacles.
Case Studies and Best Practices
Lake Ōhau Fire Response
The Lake Ōhau fire in 2020 serves as a stark reminder of the importance of fire-resilient design. The Wildfire Safer Housing Guide by FENZ outlines several best practices that could have mitigated the damage, such as using fire-resistant materials and maintaining clear zones around homes.
Mt Iron Wildfire Risk Reduction Project
In response to the increasing wildfire risk, the Mt Iron community in Otago has implemented a comprehensive wildfire risk reduction project. This initiative includes creating designated evacuation routes, clearing vegetation, and establishing early warning systems. Such community-driven efforts are vital for enhancing collective resilience to wildfires.
Designing homes for bushfire-prone areas in New Zealand requires a multifaceted approach that incorporates fire-resistant materials, defensible space, ember protection, fire-resistant landscaping, and reliable water supplies. By adhering to these principles and learning from past wildfire events, homeowners and architects can significantly enhance the resilience of homes against wildfires.
As climate change continues to increase the risk of wildfires, it is imperative that we adopt proactive measures to protect our homes and communities. Through thoughtful design and community collaboration, we can create safer, more resilient living environments that withstand the challenges posed by New Zealand’s evolving climate.