Why James Hardie / Hurricane Resistance Technical FAQ
Read answers to frequently asked questions about hurricane resistance.
The Technical FAQ section contains excerpts from the paper titled: USE OF FIBER-CEMENT IN DISASTER RELIEF HOUSING IN THE US by Basil Naji, published in the proceedings of the World Housing Congress, held in Terengganu, Malaysia, 1-5 July 2007.
What kind of winds do James Hardie® products withstand?Hurricanes (or Tropical Cyclones) cause damage and destruction from high winds, river flooding that results from intense precipitation, and storm surges (wind-driven oceanic waters). The wind speeds of historical hurricanes in the US between 1886 and 1996 are shown in the map below (figure 6). The higher risk counties along the Gulf and Eastern seaboard are clearly shown.
Figure 6: Hurricane Winds (1886 – 1996), (Source: National Hurricane Center - Atlantic and Western Pacific Databases)
The property damage from hurricanes can be staggering. It can cause damage to roofing material, bulking doors and windows, and considerable damage to mobile homes. Due to its impact resistance against hail and windblown debris, fiber-cement siding has been specified by hurricane-zone building codes for building homes in hurricane-, tornado-, and wildfire-prone areas  (figure 7). It can withstand hurricane forces winds up to 150 mph (3-second gust) provided the installation conforms to proper installation methods found within the NER-405 or Miami-Dade County Florida NOA 07-0418.04  (figure 8).
What hurricane-resistant codes do James Hardie products meet?James Hardie® siding products are deemed a FEMA Class V flood resistant material (JHBP FEMA Class V) and are approved for use in Wind Borne Debris Regions and High Velocity Hurricane Zones (Miami-Dade NOA 07-0418.04).
Figure 7: Fiber-cement siding is specified by building codes for use in hurricane-zone housing .
Figure 8: fiber-cement sided house in Jackson County, Mississippi which survived Hurricane Katrina.
What strength were the winds for Hurricane Katrina?Hurricane Katrina was one of the strongest storms to impact the coast of the United States during the past 100 years. It was the most destructive and expensive natural disaster in the history of the United States, with estimated total economic losses in excess of $125 billion and insured losses of $35 billion . On August 25, 2005, the storm made its first landfall on the southeast coast of Florida as a Category 1 hurricane. It then crossed south Florida and moved into the Gulf of Mexico, where it gained strength to a Category 5 hurricane, although it weakened before making its second landfall. According to the National Climatic Data Center (NCDC), Hurricane Katrina made its second landfall on August 29, 2005 as a strong Category 3 storm in southeast Louisiana near Buras, with 1-minute sustained winds estimated at 127 miles per hour (mph). After coming ashore in Louisiana, Katrina continued to move northeastward across Breton Sound, to make a third landfall near Pearlington, Mississippi, as a Category 3 storm with sustained wind speeds estimated at approximately 120 mph or approximately 145 mph 3-second gust (figure 9). The storm surge caused failures of the levee system that protects New Orleans from Lake Pontchartrain, and subsequently an estimated 80 percent of the city was flooded . Destruction on that scale has created a housing emergency likely to last for years, with demand outstripping the capacity of conventional construction techniques .
Figure 9: A map of Hurricane Katrina's movement.
Why does the Katrina Cottage have James Hardie siding?Katrina Cottage I is constructed with wood or steel framing and finished with fiber cement siding and a metal roof. The cottage is designed to withstand heavy rain and winds up to 140 miles per hour (3-second gust) (figure 11). It is estimated that the 308 sf model can be delivered for about $70,000 per unit .
Figure 11: Katrina Cottage I 
Katrina Cottage II is a 770-square-foot, two bedroom model in the architectural traditions of South Louisiana. The cottage is designed to take advantage of the latest approaches in panelized construction techniques, and could eventually be expanded into a full-size permanent home. At 16 by 30 feet, it has 480 square feet on the first floor and a 300-square-foot loft above. The structure can be built and delivered within three weeks for approximately $70,000 - $80,000 . The construction technique uses foam-insulated panels prefabricated by a Florida company, Home Front, specializing in panelized construction that is hurricane-resistant, energy-efficient and environmentally sustainable (figure 12). The Katrina cottage is built like a "sandwich": outer structural panels of fiber-cement board and an inner core of polystyrene foam. The cottages have been lab-tested to withstand 200-miles per hour winds .
Figure 12: Katrina Cottage II [13, 14]
James Hardie's commitment to a better understanding of building systems and practices [ video ]