Elina Thapa
September 21, 2022
Resiliency and Sustainability
Apart from providing shelter and a place of belonging, a house is also one of the biggest financial investments for many people. Homeowners pour the bulk of their savings into buying a house and then spend half their lives paying expensive mortgages. Imagine all this hard-earned investment wiped out in a single hurricane or torn apart by an earthquake! While there are many unavoidable natural disasters every year, damage to homes could be mitigated by additions/alterations to construction practices—some as simple and low budget as adding hurricane and metal straps to connect the roof and wall members. Sadly, many houses get destroyed each year during disaster events due to lack of resilient construction practices.
Hurricanes, earthquakes, wildfires, and other natural disasters, have cost billions of dollars for reconstruction and temporary habitation. Not only is property damage costly for large insurance companies, government, and homeowners, but it is also detrimental to our environment. When a disaster destroys houses, a large amount of waste is produced (broken timber, glass, metal, etc.) that cannot be reused in construction or even recycled and must be transported often far distances for safe disposal. Large scale reconstruction also uses large amounts of resources and other unavoidable environmental impacts. Thus, building resilient homes that can withstand natural and manmade disasters is more sustainable.
A resilient house is designed to perform well during a disaster event. Most minimum code requirements do not make a house disaster-proof, rather the code’s goal is to give occupants enough time for occupants to escape safely. To achieve resilience, homes must be designed and constructed to be above code. A resilient house should also be designed to perform well after a disaster. Sustainable construction practices like connecting to an off-grid power supply and rainwater harvesting can allow residents to remain in their homes immediately after a disaster by providing alternative power and water if they are damaged or disrupted after disaster events.
Various above-code standards, like NGBS Green+ RESILIENCE, LEED, RELi, FORTIFIED, and other coastal code supplements, help buildings withstand worst forms of disasters, while costing just a fraction of the base construction. In the U.S., NGBS Green is the leading green building rating system, offering resilience and different levels of sustainability. The cost of achieving resiliency and sustainability depends on the desired level.
NGBS Green certification is flexible, affordable, and yet rigorous at the same time, providing builders and homeowners with a useful national standard by which to design and build homes that are both sustainable and resilient.
Building NGBS Green and resilient structures may have a higher initial cost, but this is offset by reduced operating and maintenance cost in the long term.
The ICC-700 2020 National Green Building Standard® (NGBS) award points for homes that are designed to be resilient above code standards for new construction as well as renovation under the NGBS Green+ RESILIENCE certification. NGBS Green+ certifications are designed to provide a streamlined, supplementary, third-party recognition for NGBS Green certified homes based on their exceptional performance on specific categories like resilience, net zero energy, smart home etc. (For more information, see HomeInnovation.com/NGBSGreenPlus). While programs like FORTIFIED are designed for resistance to hurricanes or other severe weather events, the NGBS takes a more holistic approach and focuses on overall building resilience. The 2020 NGBS provides points toward certification for buildings that incorporate practices that enhance resilience, such as, selecting advanced framing techniques or structural design standards, foundation system that minimizes soil disturbance and covers 50% or more of building footprint, moisture management practices and control measures, termite barrier, ice barrier, etc. 2020 NGBS Section 613 specifically provides points for designing resilience above base construction and awards points in increment order. NGBS also recognizes practices like rainwater collection and on-site renewable energy that help achieve resiliency post-disaster to some degree.
In a perfect world, all resilient construction practices would also be sustainable and vice versa, but in the real world, that’s not always the case. There are green building construction practices that don’t improve resiliency and in fact, might conflict with more resilient construction. For example, a vegetated roof is not suitable for areas prone to hurricanes or wildfires. Similarly, the most energy efficient insulation choice is not the most fire resistant. At the same time, stronger, more resilient structures might use more resources for construction, but, of course, this is mitigated if the home remains standing after a disaster.
In situations like these, when deciding on whether to select resilience or sustainability, several factors should be considered including the site location, its climate zone as well as historical and predicted frequency of disaster in the area. Project teams should discuss overall goals of sustainability and resilience during the planning and design phase and identify tradeoffs and synergies between both. While mere common sense should guide us to build to resilient construction practices in high hazard areas that are prone to higher frequency of disaster, it should not prevent the builder and designers from incorporating other sustainable construction practices in the project because building energy efficient homes helps lower greenhouse gases emission which directly helps mitigate climate change, one of the causes of emergent natural disasters.
Resilience has always been a huge part of sustainability but with climate change impacts being ever more apparent, we can expect a roller-coaster of flood, wind, fire, and weather events to stun us more frequently in the near future. It’s high time we rethink resilience and sustainability as one entity and include both in our construction practices.
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