Hurricane Resistant Building Techniques for New and Restorative Residential Construction in Coastal Communities

Emma Curran- Environmental Science

Erika Smith- NRC

Dean Jenssen- BCT

George Baidoo- BCT

From Webster’s Dictionary, the word ‘claustrophobia’ is the fear of being enclosed in a small space or room and unable to escape or get out. Many people in the world suffer from this phobia, while others simply feel uncomfortable with the idea of being stuck in place. This is a feeling thousands of people have endured, especially in times of a natural disaster, faced with a rising storm surge and trying to escape. This is the fate many residents in hurricane prone areas, particularly the Gulf Coast and Florida have encountered. Unfortunately, a storm surge rises irrespective to one’s claustrophobia. Brendan Smialowski and Gianrigo Marletta interviewed Mexico beach resident Loren Beltran after the recent devastation Hurricane Michael caused. “My house, which is in Mexico Beach, is under water,” said Beltran, distraught after learning that water had reached the ceiling of her damaged home (Smialowski, B et al. 2018, October 11). Climate change is progressing, and factors like storm surge, sea level rise, and sea surface temperature (SST) increase are causing high intensity hurricanes to happen at a higher rate. This has led to more much more flood damage in coastal communities.  The only viable solution to better protect the homes of residents living in coastal areas is building with flood proof materials and methods, such as concrete foundations, to ensure minimal damage possible from the hurricane.

Coastal communities are already heavily developed. According to the US Census Bureau, 94 million people lived along the United States’ coastlines in 2016, about 30 percent of the country’s total population. Figures provided by the Census Bureau depict a steady positive increase in the Atlantic and Gulf Coastline populations from the years 2000 to 2016 despite the major hurricanes that have torn through those areas, such as Hurricane Katrina in 2005, Hurricane Sandy in 2012, and Hurricane Matthew in 2016 (US Census Bureau, 2018).

Although located in high risk zones, many coastal areas along the US Gulf Coast and Florida are very desirable places for people to live due to nice weather, close proximity to the beach, and many things to do in the bustling towns and cities. Despite the many good things that come with living by the beach, these areas are known to be extremely prone to hurricanes. In 2005, Hurricane Katrina caused 1833 fatalities and $108 billion property damage in several coastal regions along the Gulf of Mexico. In 2012, flooding alone from Hurricane Sandy caused over $62 million in property damage (Cui, W et al. 2016). Hurricane Harvey in 2017 damaged at least 204,000 homes along the Texas coast, where about 39 percent of homes damaged were due to flood waters up to 18 inches inside the house (Diduch, 2018; Hampton et al. 2018). Coastal cities are already extremely populated and continue to draw people in despite the known negatives of hurricanes, so it is unreasonable to expect people to not build there. In Texas, building permits are already being issued in places the hardest hit by Hurricane Harvey (Flavelle, 2018).  Since people won’t stop building in these areas vulnerable to flooding from hurricanes, and most will not opt for a safer (but more immediately expensive) building construction, it’s necessary to find a solution that minimizes the consequences of hurricane damage. that building requirements add stricter building regulations to ensure their safety. To avoid the possibility of billions of dollars in flood damage again, it should be mandatory that houses built in areas high at risk for flood damage should meet criteria for flood safety.

Hurricanes are a part of living on the coast, but climate change is making the impacts of hurricanes worse. Global warming, a consequence of human activities that releases more heat-trapping greenhouse gasses into the air, has caused the Earth’s overall temperature to increase slightly over the years. However, since Earth’s ecosystems are so intricately intertwined, what seems like a small increase to humans is actually catastrophic to natural events and other organisms. Factors such as sea surface temperature, storm surge, and sea level rise contribute to more intense, more frequent hurricanes.

One aspect of climate change that impacts hurricanes is sea surface temperature. Sea surface temperature is one of the main drivers of the formation of hurricanes, and studies indicate that there is a positive correlation between sea surface temperature and hurricane intensity (Hosseini, S. R. et al. 2018, Strazzo, et al. 2013, Mousavi, et al 2011).  Since the oceans are absorbing more heat and becoming warmer, hurricanes are forming more frequently and with more power. Several studies show that category 5 hurricanes are closely linked to rising ocean temperatures, so as climate change progresses and sea surface temperature increases, the frequency of extreme hurricanes is predicted to increase as well (Hosseini, S. R. et al. 2018, Strazzo, et al. 2013, Mousavi, et al 2011). With more category 5 hurricanes and an increasing population, worse damage is expected at a higher frequency.

Coastal populations are one of the major targets of a rising storm surge. Storm surge is the abnormal rise of ocean water above the expected tide level. It’s caused by atmospheric pressure changes and high winds that push water towards a storm center (NOAA, 2018). Climate change impacts storm surge through sea level rise. Sea level rise is caused by thermal expansion, which is what happens when sea surface temperature increases and the water molecules expand, thus warmer water takes up a larger volume and sea level rises (NOAA, 2018). Mousavi et al. (2011) indicate that flood elevations, or generated storm surge plus sea level rise, will rise by 0.3 meters by 2030 and 0.8 meters by 2080. To put this number into perspective, this would mean one to three feet of added water to the already high recent hurricane storm surge heights. The colossal damage that resulted after Hurricane Katrina has been documented by blogger Margie Kieper during a series of blog posts that she document in the summer of 2006 (Kieper, M. 2006, August). In an interview with a Judith and Bill Bradford, a couple that survived the surge staying in their Waveland home explained that an 18-inch truss between the 1st and 2nd floors, was what saved their 2nd floor from being flooded (Kieper, M. 2006, August). The storm surge for Katrina was up to 28 feet, therefore an anticipated rise of up to another three feet would be devastating. With the average height of a two story home ranging from 24 to 27 feet, both of these storm surge numbers exceed the top of the dwelling. Judith states that in a matter of only five to ten minutes, the water came up 6 feet, quickly filling the first floor (Kieper, M. 2006, August). According to Balaguru et al. (2016), with increases in hurricane intensity and sea-level rise, 30 to 154 percent more of the coastal population is at risk due to storm surge flooding. Although population density accounts for the large range of people at risk, studies suggest that very small increases in storm surge will cause an asymmetrically high impact on the coastal populations (Balaguru et al. (2016). A study focused on Sarasota County, Florida shows that contrasting ‘hurricane storm-surge hazard zones’ with a ‘120 cm sea-level rise scenario’ for a Category 4 or 5 hurricane could increase the number of coastal residents affected, accounting for 70% of the entire county’s population (Frazier et al. 2010).

Storm surge is also affected by higher winds generated from more extreme storms. Higher winds create bigger waves and can push more water past normal tide levels. With rising sea surface temperatures increasing category 5 hurricane formation, hurricanes are experiencing larger surges from higher winds. The results that Frazier et al. 2010 gathered from their research and wind-driven storm surge simulations along with Balaguru et al. 2016’s climate models and projections of thermodynamic potential intensity (PI) show that as the wind speed of hurricanes increase during the peak hurricane months of August to October, coastal cities and populations along the Gulf and Florida are more likely to face a greater amount of storm surge.

A common, yet costly effect of hurricanes is flooding. As climate change continues to cause more frequent hurricanes, more intense flooding occurs at a higher rate and therefore is becoming more expensive to repair the damages. Based on costs caused by previous hurricanes and the lack of large scale preemptive measures taken against residential flooding, damage costs will only become greater for future storms. There is lots of energy and research put towards effective methods to withstand flooding, but few regulations ensure that people include them in new buildings. New building techniques for coastal, residential new-builds or restoration building will make houses more resistant to damage from hurricane flooding. In order to prevent future severe flood damage, cities along the US Gulf and Florida coasts should make it mandatory to use concrete foundations and insulation in future and restorative residential structures to better withstand hurricanes and minimize flood damage costs.

With hurricanes strengthening over time and producing more storm surge, flooding from hurricanes across the United States has become very common. There is a growing need for a consensus on safer zoning, planning, and building regulations coastal communities in high risk flooding zones.  According to the National Institute of Building Sciences (2017), for every $1 the government puts into mitigation projects, such as raising homes at risk of flooding, improving stormwater management systems, and adding hurricane panels, reduces future costs of damage by $6. This data shows a positive return on the government’s investments in hurricane flood protection. In Florida, about 800,000 single-family houses were built last year, but only about eight percent had concrete frames (Census Bureau). Recently, there have been calls for a major reform to ensure that proper investments are made to minimize flood damage. Elected officials from coastal cities in states such as Texas, Florida, and Louisiana have come together and signed the ‘Flood-Ready Infrastructure Statement of Principles’, which was unveiled in 2017 at an event in Washington D.C. This statement calls on the federal government to make changes to building and infrastructure requirements, utilize natural defenses like wetlands, and regulate developments that are not suitable in areas at high risk of flooding (Lightbody et al., 2018). In order to prevent the recurrence of severe flood damages, future residential structures and homes that are being rebuilt after a disaster along coastal areas need to be designed with hurricane flood protection materials in order to save on rebuilding costs. By incorporating flood resistant materials into homes, complete destruction or major damages will be avoided, thus leading to low fixing costs. Important materials such as concrete, tile, brick, metal, and stone are able to withstand at least 72 hours of direct contact with floodwaters while only receiving minor cosmetic damage (Maloney, 2016). In comparison to an average wooden frame, the use of concrete between stacked foam blocks as a form of insulation (insulated concrete forms, or ICFs) has resulted in a much stronger structure that is able to withstand both hurricanes and flooding (Flavelle, 2018). Although this method can be about 15 percent more expensive than typical insulation and framing designs, this initial investment in stronger and safer building material will in the long run protect the home from future impacts. The inclusion of these materials into standard building regulations along coastal areas would significantly lower the amount of repairs to be made post hurricane. A project located in a FEMA D-Rated area (susceptible to undetermined flood hazards) in Putnam County, Florida used this method. This particular home was hit directly by Hurricane Matthew and emerged with only minimal damages. It was recorded that storm surge rose over the house’s front patio, but no water was able to get through both the exterior and interior concrete-insulated walls and enter the home. Although the house withstood winds around 160 MPH during the hurricane, the ICF it was built with are made to sustain up to 250 MPH. In addition to security from hurricane winds and flood waters, homes built with ICF are extremely energy efficient (ICF Builder, 2017). The homeowner stated that the energy bill has not gone above $18 per month, while the Florida average is up to ~$129, according to a 2018 estimate (ICF Builder, 2017, Josephson, 2018). In an experiment done by Flynn et al. 2010, it was found that applying a ½ inch of stucco, a type of cement plaster, to concrete block walls significantly improved its water resistance. After a 4 hour testing period of wind-driven rains that reached 62 MPH, a 24 hour test was done where 110 MPH wind-driven rains were reached. The latter test’s winds are comparable to those of a Category 2 hurricane, which typically have winds that range from 96 to 110 MPH (Flynn et al, 2010, pg. 64,  National Hurricane Center). When a concrete block wall with no stucco materials included underwent the same experiment, Flynn et al. 2010 found that the wall was much less water resistant and began showing leaks at just 62 MPH, which is less than the 74 to 95 MPH winds that are typically categorized for Category 1 hurricanes (National Hurricane Center). A paper by Hochrainer-Stigler et al. 2018 illustrates an application of a benefit-cost analysis (BCA) for assessing investments in structural flood-proofing of low-income, high-risk houses in India. The estimates of the paper by Hochrainer-Stigler et al. 2018 shows a positive benefit-cost ratio for building new houses on a raised plinth, while the ratio is less than one for demolishing existing houses to rebuild on a raised plinth. Putting effort into safer, more flood resistant structures now will lead to much lower costs of repair in the future. This is one of the main ways houses are strengthened against extreme weather, however even in areas at high risk of extreme flooding homeowners opted for less safe options because they are immediately cheaper, despite the data that shows there is a large long term payoff.

Despite a higher initial building cost for safer hurricane and flood-proof homes, it is clear that the investment will save many states hundreds of millions, or even billions of dollars in rebuilding expenses. Too many homes in the Gulf Coast and Florida do not have foundations that are able to withstand the intense flooding, leaving homeowners with high repair costs at a higher frequency. We are not able to reverse the impacts of climate change at a rate that helps current residents, so measures need to be taken to mitigate the damage that will certainly occur. Areas prone to hurricane damage need to enforce building regulations that ensure people incorporate materials like concrete into their structures, rather than opting for an immediately cheaper option. Incorporating ICF into coastal city zoning and planning regulations would have several positive effects in communities. These buildings are much more stable structures than common wooden frames, so severe damages to communities would be easily prevented. ICF structures are also extremely energy efficient, so another way that investing more initially pays off in the long run is that monthly energy bills greatly decrease due to the concrete wall’s thermal mass. While many officials and mayors in cities greatly affected by hurricane damage have advocated for regulations to change for safer living, we are still a long way from getting this goal accomplished. More research on the benefits concrete insulation over typical wooden frames has come out recently, with experiments simulating hurricane-like winds and storm surges. With the success of these experiments, and concrete insulated walls holding up and keeping water out, there are hopes that in the near future, zoning laws will be adjusted to protect new builds in coastal communities. With the main concern being finances, it is important to remember that the investments made now are in stronger, more stable and resistant structures that will not have to be rebuilt or majorly reconstructed after each storm. With this, and the addition of lower energy costs, insulated concrete forms are a perfect substitute for wooden frames in new construction along the US Gulf and Florida Coast.

What do we do?

Evidence of effectiveness

ICF is being used in many parts of canada and the united states. The federal emergency management agency(FEMA), an agency in the U.S department of homeland security whose purpose is to assist in a distature that has occured in the United states. FEMA advocates for ICF over wood insulation in more hurricane prone areas including Florida and the gulf coasts. A brand new Florida home that was build with Logix ICF was left untouched after it was hit by a category 5 hurricane Matthew in 2016 with winds up to 165 miles per hour. The home was later hit again by Hurricane Irma in 2017, the water was surrounding the home, but everything inside was completely dry and was not affected at all from the winds or flooding. The home was not affected because of the “superior-energy” efficiency of ICF.

Offer a discounted price to communities in Florida who use are rebuilding with ICF’s

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