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Residential architects who specialize in the hot, humid, southern climate

Designing for Hurricanes

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The National Oceanic and Atmospheric Association’s Climate Prediction Center (NOAA’s CPC) is predicting an “above normal” hurricane season with 11 to 17 named storms, 5 to 9 hurricanes and 2 to 4 major hurricanes over category three. The historic method of learning about building performance is through experiencing hurricanes such as Matthew and Irma in 2016 and 2017, respectively.  The better, less risky way is through research.

The nonprofit Insurance Institute for Business & Home Safety (IBHS) has a research center in Chester County, South Carolina.  The building performance testing is done on full-scale 2- story models in a 21,000 square foot, 6 stories tall building. They can create a broad spectrum of weather – ranging from hurricane conditions, windstorms, wildfires, and hailstorms. They use the data to develop best practices in building construction.

The research center also has a “roof farm” which is an exterior installation to test decay and deterioration caused by severe weather. This allows them to conduct long term evaluations on new materials and systems.

Recently, a contractor said to me that impact windows were a waste of money because they still can crack and the insurance will pay for any damage anyway. This is false logic. The IBHS research shows that a key mitigation step is protecting the windows and doors with either impact rated windows and doors, shutters, or plywood. When the openings are not protected, wind pressure can build up inside the house. Then, when a door or window is forced open, the roof blows off and the walls can collapse.

Their research also shows that roof cover damage is the most frequent source of hurricane related insurance claims. Metal roofs tend to perform better than asphalt shingles but it is essential for the roofing material to be rated for high wind speeds. The roof assembly, deck, flashing, and the approved roof cover all must be installed to be the current building code.

Fortunately, here in South Carolina, we have stringent building codes. The IBHS rates the 18 hurricane-prone states on the quality of their building codes. Of the 18 states, South Carolina is third with a score of 92. Florida (95) and Virginia (94) are first and second, respectively.

Julie Rochman, former IBHS CEO, said “ States with strong, updated codes saw stunning proof this year that updated, well-enforced building codes have led to the construction of homes and buildings that can stand up to fierce hurricane winds. It can’t be any clearer: these codes work.”