Can buildings withstand Michael's ferocious winds based on current codes?

(Photo: NOAA)

(Photo: NOAA)

As Hurricane Michael stays on course to slam into the Florida panhandle this afternoon, some people may be wondering if homes and other buildings can handle the Category 4 winds. Since Andrew demolished parts of south Florida in August of 1992 with Category 5 winds of more than 155 mph, state officials looked at building codes and began to making changes.

After Andrew, Florida adopted the strictest building codes in the nation. For example, codes began requiring the use of plywood in roof construction instead of particle board. Instead of roofing nails, staples hd to be used. Other new codes required specifications such as shatterproof windows, roof fortification, and reinforced concrete pillars, just to name a few.

The Real Deal, a real estate publication in South Florida, reported last September that builders had to begin making sure their structures could withstand winds of at least 111 mph in most parts of the state; at least 130 mph in Miami-Dade and Broward Counties in south Florida.

The mandatory codes went into effect in 2002, including rules on everything from windows and doors to skylights - anything that could let in wind. Their first test came in 2004 when four hurricanes hit the state: Charley, Frances, Ivan, and Jeanne.

A report from FEMA found that homes built after the codes took effect held up better than homes prior to the codes. A separate report from the Insurance Institute for Business & Home Safety found the owners of post-Andrew homes filed 60% fewer insurance claims and the severity of those claims was 42% lower. The institute also said about 80% of the homes in the path of Hurricane Irma in 2017 were built after the new codes took effect, and those homes also fared well compared to pre-codes homes.

However, after the Florida Building Commission analyzed data from the four storms it decided to re-calibrate how much wind a Florida home would need to withstand, citing too much “over-designing” in 2005.

During last year’s legislative session legislators pushed for big changes which slacken the codes a bit, including a proposal calling for state officials to freeze the code as it stands with only occasional updates. Another proposal called for a six-year cycle instead of a three-year. Negotiations ended with a compromise: The codes would still be updated every three years but would no longer adopt to the codes of the International Code Council (ICC). Instead, Florida would keep its current code and choose which parts of the ICC code to adopt.

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Mario Gisbert, City Manager of panama City, Florida, told the Today show this morning that lots of buildings in the city made it through Hurricane Opal okay back in 1995, before the codes were tightened. Opal produced winds of 115 mph at landfall. However, he didn’t take any chances in getting as many people evacuated as possible. He said about 50% of locals have left as well as most visitors.

The takeaway: Michael will cause extensive wind damage to homes, offices, and other buildings, but it remains to be seen if the damage will be as devastating as that produced by hurricane Andrew prior to the new building codes. Trees and power lines will definitely not be able to handle the impact.

Michael is very dangerous, life-threatening Category 4 hurricane. As of 11 a.m. EDT Wednesday, sustained winds had increased to 145 mph. Gusts of 68 mph have been reported in Apalachicola. The storm is closing in on the Florida panhandle and is centered just 60 miles southwest of Panama City, Florida. The National Hurricane Center expects landfall early this afternoon.

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This would be the first Category 4 hurricane to ever make landfall on the Florida panhandle.