Natural disasters frequently strike New Zealand, which is a country especially vulnerable to earthquakes, floods and tropical storms. Although we cannot stop these disasters from happening, we can future-proof new builds to endure unexpected events.

To safeguard New Zealanders and minimise damage, residential design must prioritise the longevity of Kiwi homes and resilient construction.

NZ is located in a seismic zone, meaning the country is vulnerable to earthquakes.

Earthquakes have the potential to cause significant damage; the 2011 Christchurch earthquake being the most notable in the country’s recent history. This earthquake caused devastating damage to the city, taking the lives of 185 people, with many sustaining serious injuries, much due to the collapse of buildings. The existing homes were not able to withstand the magnitude of the seismic activity, resulting in thousands of residential homes in need of repair or rebuild.

ECONOMIC IMPACT

Residents of Christchurch were significantly affected by this tragedy, and it also had a substantial economic impact. This event led to changes in the NZ seismic building code, to improve building resilience in these affected areas.

NZ is also susceptible to tropical storms; most recently we witnessed the devastating impact of Cyclone Gabrielle. Homes were flooded, structures and roads destroyed from land slips, and many experienced leaky roofs from the destructive winds and heavy downpours.

The number of insurance claims related to the floods and Cyclone Gabrielle reached 70,000 in Auckland alone. The insurance industry as of early March was expecting costs to be over $1 billion. Damages as a result of these natural disasters are severe, and much attention is now placed on the quality of new builds and how they will withstand such unexpected events.

CONSTRUCTION SYSTEMS

Choosing the right construction system is crucial for resistance against earthquakes and cyclones. Ultimately, a well-designed and well-constructed building can save lives and reduce damage caused by natural disasters.

Steel framing makes for an ideal solution to strengthen a building as it offers good ductility, which means it is able to bend in the event of an earthquake without breaking or cracking.

Among the many construction systems available, insulated concrete forms (ICF) have gained popularity due to their durability and efficiency in natural disaster resistance. ICF is a construction system that uses polystyrene foam blocks as a mould for poured in place concrete walls. The foam blocks interlock with each other, creating a hollow cavity which is filled with waterproof, steel reinforced concrete. The reinforced concrete in ICF structures is well-suited to resist natural disasters such as earthquakes and cyclones. The rigidity and mass of the reinforced concrete walls make ICF buildings resistant to seismic activity.

ICF walls demonstrate wind resistance, where they are capable of withstanding cyclone-level winds without walls collapsing inward, reducing the risk of injury.

The durability of ICF structures is also shown in their ability to resist floods and water damage due to their watertight materials. The water resistant foam blocks combined with the waterproof, swimming pool formula reinforced concrete, eliminates the ability for water to penetrate the building’s external envelope.

The strength of ICF has been demonstrated in the previously mentioned Christchurch earthquake. There was a building that endured and remained standing in a red zone street. This building is the Fino Hotel, which was constructed entirely from ICF.

POST-DISASTER LESSONS

Natural disasters are a recurring threat to communities and their infrastructures. A post-disaster construction strategy should take into account materials and systems that specifically provide the best protection against these conditions as NZ is particularly susceptible to earthquakes and tropical storms.

Poor infrastructure puts people at risk and has an adverse economic impact, which is more than enough justification for NZ builders to seriously consider future-proofing all new developments.