Another key factor was Hurricane Charley, which Glenn called the “ultimate test” of tougher standards the Florida Legislature enacted in 2002 after a decade of wrangling with the powerful development lobby.
After Charley hit the Southwest coast with 150 mph winds in 2005, damage surveys conducted by the University of Florida showed homes built under the 2002 code suffered far less damage than older ones. That made a case that “very conservative’’ standards could be rolled back in lower-risk zones, Glenn said.
“The general feeling was that in 2005 we were over-designing,’’ he said. “We needed to relax a bit because there is a cost impact.’’
Costs have always been a consideration in code calculations, said Glenn, with the aim of finding a prudent balance between structural integrity and affordability.
Generally, the higher the projected wind load, the higher the cost of construction. Depending on location, builders estimate wind codes add from 1 percent to 5 percent to home prices — thousands, even tens of thousands of dollars.
“We have to make structures that people will buy and live in,’’ Glenn said.
Though often misunderstood, building to code doesn’t mean designing for worst-case scenarios like a Category 5. Instead, the goal is to protect lives and minimize property losses from more likely risks.
The state’s wind-speed map, for instance, is based on a projected 3 percent chance that a region will be exposed to gusts of certain speeds at least once in 50 years. The wind speeds are key to the complex calculations of the winds loads or pressures that buildings are supposed to withstand.
For most homes and buildings, those speeds now range from 180 mph in the Lower Keys to 115 mph in inland North Florida, with Miami-Dade at 175 mph and Broward at 170 mph.
Tim Reinhold, vice president of engineering for the insurance-industry-supported Institute for Business and Home Safety in Tampa, which has long pressed for tougher hurricane codes, called the lowered wind loads “realistic’’ and said he didn’t expect them to result in substantially weaker building designs or materials. Standard products like roof shingles, he said, typically have safety margins 50 percent higher than they are rated.
“They’re backing off wind loads a bit,’’ he said, “but it’s probably not enough to really get you in trouble.’’
In Miami-Dade and Broward, building officials also see little effect, with impact windows and shutters already meeting new standards.
Still, some South Florida-based experts question why the rest of the state would accept relaxed standards, given the devastating lessons of Andrew, the nation’s most expensive natural disaster until Hurricane Katrina nearly drowned New Orleans in 2005.
Most of South Miami-Dade escaped Andrew’s worst winds, among the most intense on record. Engineering surveys and grand jury probes in the aftermath showed inadequate codes, worsened by shoddy workmanship and sloppy enforcement, contributed heavily to the damage.
Cheaper vs. safer:
The balancing act
Eugenio Santiago, Key Biscayne’s chief building official and longtime advocate of stricter standards, believes the bottom-line concerns of the building industry continue to exert too much influence in setting wind codes — at least outside of Miami-Dade.