Is Your House Ready For The Next Natural Disaster?

Updated: Nov 24, 2020


The effects of natural disasters on people’s lives vary by year and geographical location. They may come from weather events such as blizzards, hailstorms, droughts, floods, heat waves, hurricanes, lighting strikes, tornadoes, and tsunamis; or from non-weather events such as earthquakes, mudslides, volcanoes, and wildfires {1}. In the U.S., many regions suffer constantly from natural disasters. The most damaging are often wildfires, hurricanes, floods, tornadoes, hailstorms, and earthquakes. However, many structures present a lack of readiness to these natural phenomena, especially residential structures. This causes billions of dollars in damage, lives lost, and economic wreckage to many households.

In 2017, hurricane Harvey alone caused $180 billion in damage in the Houston metropolitan area {2}. In the short term, it displaced many families from their homes, while the recovery process took place, for a couple of months to even years. The U.S. government estimated that 100,000 houses were either destroyed or damaged. About 30,000 people had to stay in shelters {3}. Many others had to stay with relatives or in hotel rooms, while some others relocated to other areas of the country. Similarly, wildfires in California in 2017 and 2018 caused a lot of damage. They killed a total of 144 people, burned 3.5 million acres and destroyed 36,000 structures {4}.

“Not only the amount of damage seems to be increasing, but also the number of regions in the country being affected.”

Some reports show an increase in the amount of natural disasters in recent years, even as high as three times the amount from 2000 to 2009, compared to 1980 to 1989 {5}. The average number of declared major disasters per year from 1996 to 2019 is 58, compared to 28 from 1953 to 1995, according to FEMA {4}. Additionally, the effect these disasters have seems to be also increasing, in part due to a growth in urbanization. The 2017 natural disaster season was one of the worse in recent history. It tied the 2011 season for the most events (16 total) causing $1 billion or more in damages, when adjusted for inflation. There has been a total of 215 such events from 1980 to 2015 {6,7}.

In 2019, the president declared 61 major disasters. Such events affected more than one-third of the country (1,210 of the nation’s 3,142 counties), with 105 million of the 327 million population residing there {4}. These numbers show the widespread of natural disasters, which is also of concern. In the long term, natural disasters may slow down economic growth in a region, destroy valuable transportation infrastructure, and cause many households, unable to rebuild their homes, to relocate {1}. Those that are uninsured, risk financial ruin and even homelessness. Not only the amount of damage seems to be increasing, but also the number of different regions in the country being affected.

Relocating doesn’t solve the problem.

A risk map developed by ATTOM in 2016 shows the areas in the country of higher risk. They indexed more than 3,000 U.S. counties based on the risk of six major natural disasters: earthquakes, floods, hail, hurricane storm surge, tornadoes, and wildfires. They were divided into five equal groups (quintiles) based on the natural hazard risk index and assigned to one of five risk categories: very high, high, moderate, low, and very low. As expected, many of the coastal counties in Florida, Louisiana, Alabama, North Carolina, South Carolina, and Texas, were found to be high to very high risk due to hurricane storm surge. Most of the state of California is considered moderate, high, and very high risk. Mostly due to earthquakes, wildfires, and floods. Some counties in other areas of the country, such as Oklahoma, Kansas, and Nebraska, are more at risk of hail and tornadoes, ranking in the very high quintile of the country for those disasters {8}.

This study also observed a trend in the relocation of many households from higher to lower risk areas. When comparing the change in homes sales in the previous five years, they found a significant difference between the very high and very low risk counties for earthquakes, floods, hurricane storms surge, and wildfires. Counties with very low risk saw a significantly higher increase in homes sales than those in very high risk for the aforementioned natural disasters {8}.

Many people migrated from 2011 to 2016 to avoid risking their lives and property from being destroyed. However, as they relocated to other parts of the country, they most likely found themselves in regions of medium to very high risk for other natural disasters, such as tornadoes and hailstorms. This is shown by the same study, which found a significantly higher increase in home sales for high risk areas of tornadoes and hailstorms, when compared to low risk areas of the same natural disasters {8}. As people moved away from the coasts, rivers, and forests, they most likely relocated to plains, which are more prone to tornadoes and hailstorms.

“It seems natural disasters, of different varieties, threaten homeowners in many areas of the country, regardless of relocation efforts.”

It seems natural disasters, of different varieties, threaten homeowners in many areas of the country, regardless of relocation efforts. With such high numbers in terms of economic damage, instead of trying to relocate millions of people, the solution must be in the improvements to the way residential structures are built. Although the recent wave of disasters has brought about changes to building codes, many traditionally built homes are still not equipped to withstand high wind forces, wildfire temperatures, or impact due to flying debris.

Resistance to natural disasters.

In the aftermath of Hurricane Katrina, some of the people who lost their homes were relocated to manufactured housing and travel trailers. They ended up blaming such housing for causing severe breathing and other medical problems. The use of such housing was later assessed by FEMA to help victims of Hurricane Harvey and it was found to be a costly solution. It can cost as much as $250,000 to purchase, set up and maintain a unit. According to FEMA, making fast, minimal repairs to allow people to return to their homes while further repairs are being completed is preferable than using manufactured housing and travel trailers {3}. In that sense, home resilience has become an important topic of discussion for regions high in risk of natural disasters.

The ability of a residential structure to withstand a natural disaster, even if mildly affected by it, could save thousands of homes from being destroyed, and billions of dollars to property owners and insurance companies. An example is a home that survived the Valley Fire wildfire in Lake County, California in 2015. This house was built using offsite construction methods. It used pre-manufactured, interlocking panels covered with a reinforced concrete layer. It only suffered window damage and soot cover in some areas inside. Even though its construction cost 20% more than a traditional wood frame house, it was well worth the investment after all the other houses in the area were destroyed completely {9}. This type of resilience in a wildfire was possible due to the fire-resistant concrete used in its wall construction.

“The ability of a residential structure to withstand a natural disaster, even if mildly affected by it, could save thousands of homes from being destroyed, and billions of dollars to property owners and insurance companies.”

Materials selection has become increasingly important for resistance to natural disasters, including wildfires. The average forest fire has flames with temperatures up to almost 1,500 degrees Fahrenheit (800 degrees Celsius). Considering wood begins burning at around 572 degrees Fahrenheit, more resistant materials are needed {10}. Tile and steel are recommended as roofing options, and cement or stucco materials as siding options {11}. Even though those materials are not completely fireproof, they do increase the level of resistance and give a higher probability for the home to withstand.

Similarly, having a hail-resistant material on the roof can help limit the damage caused by a hailstorm. Such materials include asphalt, metal, slate or tiles roofs, which also help resist high wind caused by major storms {11}. High winds are the main cause of damage to homes during tornadoes and hurricanes. Traditionally built homes are usually not prepared to withstand the forces associated to such winds and flying debris {12}. Window resistance to natural disaster is also important. To protect from hail damage, high winds, and flying debris caused by tornadoes, hurricanes, and other storms, window shutters are usually recommended. If window shutters are not available, installing impact resistant windows is another option to help resist some of the damage. Windows with rounded corners are also suggested to reduce cracking {11}.

The strength of the overall structure is also of high importance. When designing for hurricane resistance, FEMA suggests reinforcing cripple walls, chimneys, and the roof; and making sure the walls have steel frames and are well anchored to the foundation using sill plates. In general, there are two main areas of hurricane preparedness related to the structure envelope. Anchoring the roof to avoid lift-up from high winds; and increasing the impact resistance of walls, windows, doors, and roof to protect from flying debris {13}. It is also recommended to create load path continuity from the roof to the walls, and from the walls to the foundation {12}. This helps avoid roofs from flying off and increases the bending strength of walls and windows to impacting objects.

Resistance to a tornado requires similar preparedness in terms of the building envelope. Improvements in materials and structural strength does not make a house tornado proof. For that, a concrete box strongly anchored to the foundation, with no windows and a steel door would be necessary {11}. However, these improvements do help reduce the risk of costly damage. While a strong structure is desired to resist impact and high winds during storms, ductility is needed when preparing a residence in an earthquake risk zone. Ductility allows a structure to bend or stretch without breaking. A material such as steel, highly ductile, should be used in the structure to prevent building collapse during earthquakes {12}.

As of 2018, in the U.S., about 36 million people reside in places with a high risk of flooding {12}. Resistance to flooding is one of the most difficult tasks when designing a resilient house, even though flooding is the most common natural disaster. The common solution is to build the house on an elevated lot or on stilts, if one is near a coastal area. Also, grading the property properly allows water to drain; planting trees helps prevent soil erosion {11}. However, flood waters sometimes rise higher than expected, even when building away from flood plains. Thus, it is important to use materials on the building envelope that reduce water penetration. High-quality concrete has low water permeability {14}. It is commonly used in dams and channels for water control. Concrete walls are recommended for increased flood resistance.

Home durability.

Building a home resistant to natural disasters seems a daunting endeavor. Nevertheless, there are three main points that can help guide the decision-making process. First, a resilient home will be a durable home. Lasting structures are better for the environment because they help avoid material waste generated when demolishing a damaged one. The rebuilding process requires additional materials that already underwent an industrial process to manufacture them. All this rebuilding is largely unnecessary if houses were more resilient to disasters. Even if some damaged is incurred, fixing a resilient house requires much less effort than rebuilding. Therefore, the added resistance will contribute to longer durability.

Second, many of the materials needed to increase resilience to a particular natural disaster are also helpful to withstand others. For example, a concrete wall can help decrease water penetration during a flood, increase impact resistance to airborne objects during a tornado or hurricane, and decrease flammability to wildfires. Similarly, the roof, windows, foundation, doors, and structural components can all be designed and selected to increase resistance to natural disasters. Research efforts by government and private laboratories will continue to develop new materials for the construction industry that will further the pursuit of natural disaster resistance. It is the job of the builder to find and use the best materials available.

“Durable homes should not be a luxury reserved to wealthy households. If that’s the case, many will continue to suffer from the devastation of natural disasters in the years to come.”

Third, a resilient, durable home will have a lower cost of ownership. Although most insurance companies haven’t seen many homes with the resistant capabilities outlined above, more evidence coming from recent disaster zones will convince them of the difference between traditionally built and resilient structures. This advantage will eventually translate into lower homeowner’s insurance premiums. Additionally, the degradation of the house materials due to the surrounding environment will occur at a slower rate. This will translate into lower maintenance costs for the homeowner in the long term.

Finally, a durable home can also be an affordable home. Durable homes should not be a luxury reserved only to wealthy households. If that’s the case, many will continue to suffer from the devastation of natural disasters in the years to come. A different approach to homebuilding needs to be adopted to provide durable and affordable housing.

Petros Builders has developed a house design using resilient materials, such as concrete walls and metal roof panels; and properly reinforced roof-to-wall and wall-to-foundation junctions. Such design can withstand high winds, resist impact of flying debris, including hail, and maintain its strength under exposure to fire {15}. Additionally, a proprietary window and door shutter design can help provide resistance to rising waters.

Petros' approach to offsite construction uses manufacturing methods to build wall and roof panels more efficiently. By housing its manufacturing operations under a controlled environment, Petros can produce high-quality components consistently. Such repeatability allows for economies of scale to be introduced into the process, which generates cost savings for the customers. The materials selected and the structural design of the house make it more durable, specially to natural disasters. The method of construction makes it affordable.

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1. Amadeo, K. Natural Disasters’ Economic Impact. the balance (2019). Available at:

2. Paris, E. The Natural Disasters Of 2017’s Impact On The Housing Market Will Surprise You. Forbes (2018).

3. Fessler, P. At Least 100,000 Homes Were Affected By Harvey. Moving Back In Won’t Be Easy. NPR (2017).

4. Frank, T. Fires and Flood Cap Off a Decade of U.S. Disasters. Scientific American (2019).

5. Hill, C. 43% of U.S. homes are at high risk of natural disaster. MarketWatch (2015).

6. Mooney, C. & Dennis, B. Extreme hurricanes and wildfires made 2017 the most costly U.S. disaster year on record. The Washington Post (2018).

7. McGrath, M. Most expensive year on record for US natural disasters. BBC News (2018).

8. Realtytract. 2016 Home Sales Increasing Twice as Fast in Counties with Low Natural Hazard Risk Compared to High-Risk Counties. RealtyTract (2016).

9. Bahney, A. These homes can withstand hurricanes, earthquakes and fires. CNN

10. Gabbert, B. At what temperature does a forest fire burn? Wildfire Today (2011).

11. Is Your New Home Safe from Natural Disasters? NewHomeSource Available at:

12. Heigl, C. How Building Design Has Evolved in the Wake of Increased Natural Disasters. Construct Connect (2018).

13. How to Build a Hurricane-Resistant Home. NewHomeSource Available at:

14. Goguen, C. 5 Rules of Watertightness. Precast Inc. Magazine (2012).

15. Petros Builders. Home. (2020). Available at:

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