Study: Upgraded codes helped withstand winds
Experts find homes built under stringent standards set in 2002 fared better through last year's hurricanes than those built earlier.
By JEFF HARRINGTON
Published June 29, 2005
Ever since Hurricane Charley ripped through Port Charlotte in August, leaving a bizarre trail of totaled and virtually unscathed homes, anecdotal evidence seemed to support one theory: Homes that were built after the state's updated building code of 2002 often fared much better through the big storms than older homes, even those just a few years older.
Now a study backs up those tales.
Engineering researchers from three state universities examined the fate of 195 homes that endured peak winds from hurricanes Charley, Frances, Ivan and Jeanne last year. Among their conclusions, presented Tuesday during a meeting of the Florida Building Commission in St. Petersburg:
Single-roofed homes built under the 2002 code retained more asphalt shingles than homes built under the 1994 code.
In Charlotte County, nearly 30 percent of surveyed homes built under the 2002 code that faced wind gusts as high as 150 mph from Hurricane Charley had no shingle damage. In contrast, every surveyed home built under the previous code experienced at least some shingle loss.
None of the surveyed homes with reinforced garage doors had significant door damage, but many homes built before tighter building codes of 1994 had weaker garage doors that were blown off their tracks and suffered interior wind damage.
To Kurt Gurley, a University of Florida associate professor of engineering and lead investigator on the project, the study gives weight to those who contend Florida's tightened building codes "have made a measurable difference" in limiting storm damage.
Researchers from UF, Florida International University and Florida A&M University did not analyze homes that were built before 1994, when the building code's "high wind standard" became widely used in coastal areas.
The findings are more than academic.
The building commission, which funded the study with a $90,000 grant through the Florida Department of Community Affairs, is weighing the next round of building code changes in light of last year's devastation.
The commission's hurricane research advisory board plans to make recommendations on building code changes today as the group resumes its meeting in St. Petersburg.
Among possible changes: making roofers use a uniform method for installing tile roofs, instead of a manufacturer's recommendation; requiring hurricane shutters in some cases; and improving the construction of soffits. Soffits, vents underneath roof overhangs to allow air to circulate in attics, were a common problem during the hurricanes. Wind often damaged or blew out soffits, allowing wind-driven rain to enter an attic.
"The building code is doing a good job, but there are some tweaks that could be done," said Jeff Burton, building code manager at the Tampa-based Institute for Business and Home Safety. Burton was involved in the university study and a related institute study that looked at building permits pulled poststorm in the area hardest hit by Hurricane Charley.
"Our biggest recommendation is we would like the state of Florida to consider setting up a task force to look at how data is collected by these (local) jurisdictions," Burton said, citing a lack of consistency in how various building departments and property appraisers compiled information after the hurricanes.
Many of the findings weren't surprising. For instance, in the ongoing debate over whether to use a mechanical fastener or adhesive to install tile roofs, researchers found that homes that used both methods fared best.
Overall, both studies indicated, newer was better. But Gurley said shingle statistics on homes built since the 2002 code, for one, prove the building code changes made a difference. For the few new homes that suffered shingle loss, most had minimum damage of less than 5 percent.
In at least one case, new wasn't necessarily the best. Burton said researchers found that the owner of newer pool enclosures, or cages, had to replace them after the hurricanes at a higher rate than owners of older cages.
The cages "are getting larger and larger and that could make them more vulnerable" to high wind, he surmised.
Jeff Harrington can be reached at harrington@sptimes.com or 813 226-3407.