Forensic engineers play leading roles in
setting future building policies
Garry McAlpin, an inspector under contract to FEMA, inspects a
home damaged by Hurricane Charley.
The hurricane shifted the 1930s-era waterfront home off its
pilings, sending them shooting through the living-room floor. That
much was clear. Wilbur T. "Dusty" Yaxley's job was to find out
whether the storm's winds or surge were to blame.
Yaxley, of Seffner, Fla., is among a small cadre of structural
forensic engineers whose date books filled as four hurricanes
struck Florida last fall. Their job: To distill, from a home's
jumbled and sodden remains, the drama of how wind, rain, flooding,
construction, materials, or a combination led to its demise. Hired
by insurers, homeowners, or builders, forensic engineers typically
help settle private disputes about who should pay for repairs. But
as building costs escalate and a river of new non-field-tested
materials reaches the construction market, they're also playing a
bigger public policy role.
Yaxley noticed that although water entered the house, the waterline
was near the floor, suggesting the surge's force wasn't sufficient
to move the structure. But what cinched the case was that the line
was not parallel to the floor, meaning the house was already
listing off the pilings before it flooded.
End result: The wind insurer had to write the check.
Most cases aren't so clear-cut. The confusion common in chaotic
post-hurricane devastation is the very thing that gives forensic
engineering its biggest challenges — and greatest power.
That's particularly true in a post-storm public arena, when
constituencies of homeowners, home builders, insurers, and
bureaucrats vie to evade responsibility for widespread
A strict interpretation of the Florida Building Code suggests
that application of self-adhesive underlayment directly to the roof
deck is a violation. Instead it must be applied over a nail-down
roofing felt — a rule identified as "stunningly
Case in Point: Central Florida
Take, for example, the 2004 hurricane-induced moisture problems in
Central Florida homes: At least 680 homeowners in Orlando's Orange
County, and hundreds more in four neighboring counties, complained
water poured through their windows and walls, ruining carpet, wood
floors, and cabinetry. Many residents and insurers claimed home
builders cut corners, with hundreds of insurers reportedly refusing
Stung by the allegations, the Florida Home Builders Association
(FHBA) hired a forensic engineer and leading national expert on
moisture-related building problems, Joe Lstiburek, to investigate.
Lstiburek analyzed the complaints, observed local builders at work,
and did experiments on separate systems, such as stucco-covered
His January 2005 report found the storms constituted "overwhelming"
weather, causing failure in systems that would hold up to more
moderate conditions. But he also faulted the Florida Building Code,
regional code-enforcement practices, building materials such as
housewraps, manufacturing testing standards for such major
components as windows — in short, a multiplicity of elements
in Florida homes. "There were at least a dozen things we could do
better and should do better next time around," Lstiburek
As one of several "stunningly stupid" shortcomings, he singled out
a Florida Building Code requirement that waterproof self-adhering
roof membranes be attached to nailed-down roofing paper rather than
directly to the sheathing. If hurricane-force winds blow off the
shingles, they can pick up and carry away the roofing felt and the
waterproof material at just the moment when it would be needed
most, he said.
On the sensitive issue of workmanship, Lstiburek said he found some
"atrocious" examples, but they did not constitute consistent,
repeated causes of the flooding.
From Blame to Prevention
While home builders would have liked to put all the blame on
extreme weather, they will likely use the report in their defense
in damage disputes with insurers or homeowners. "I think they would
be foolish not to," said Jack Glenn, director of technical services
for the FHBA.
But Glenn said the FHBA's main goal in hiring Lstiburek was to
pinpoint causes of water damage and ways to prevent it in future
homes. The association will tap Lstiburek's findings as it seeks to
influence the 2006 revision of the Florida Building Code, he said.
In the meantime, staffers are developing a training program on ways
contractors can beef up water protection in homes.
Florida's hurricanes are only the latest cause of the increasing
demand for structural forensic engineers, Lstiburek noted. "We have
more problems because we're building with different materials, and
these materials are put together in ways nobody ever thought of or
considered," he said. "And in many cases it takes an extreme set of
circumstances for people to take a breath and ask the question,
‘Why are we doing it this way?' That's what I do." —
To meet the demand for new roofs, out-of-state
roofing contractors flock to the storm-torn Sunshine
Roofing contractor Dan Walters has spent two months living with his
crew in cheap motels nearly 1,400 miles from his family. But the
60-hour workweeks and abundant jobs in hurricane-devastated Florida
make the conditions worthwhile for the New York-based contractor
and his eight employees, who would normally spend the winter idled
or doing other work.
The U.S. Army Corps of Engineers' "Operation Blue Roof" covered
143,000 storm-damaged roofs last fall, while local jurisdictions
gave out 500,000 smaller tarps to help keep water out of homes. Six
months later, many of the tarps remain.
"A lot of companies lay guys off in the winter," says Walters,
owner of Hamburg, N.Y.-based Coast to Coast Restoration. "We wanted
to keep our guys working, plus I've got new equipment I want to pay
Walters, whose company has reroofed about four homes weekly since
arriving in Southwest Florida in late November, is hardly alone.
Hundreds of roofing contractors from states as from away as Texas,
Kentucky, and New York relocated to the Sunshine State following
quadruple hurricane strikes last fall. With an estimated 300,000
roofs in need of replacement statewide and only about 2,500 active
state-certified Florida roofing contractors, out-of-staters have
helped Floridians get out of the rain, says Steve Munnell,
executive director of the Florida Roofing, Sheet Metal and Air
Conditioning Contracting Association.
But the migration has also caused some problems. For out-of-state
roofers, these ranged from confusion about the rules for setting up
shop in Florida to allegations that supply houses reserved
much-in-demand shingles and other supplies for local
Some out-of-staters also had trouble obtaining Florida workers'
compensation insurance, one of the requirements for the temporary
roofing contractors' licenses first made available in September.
According to Munnell, few Florida private market insurers wrote
workers' comp policies for out-of-state roofers, leaving those
whose policies didn't transfer from home with only one option: the
state's expensive insurer-of-last-resort, the Florida Workers'
Compensation Joint Underwriting Association.
Roofers from as far away as Texas and New York State have
traded the slow northern work season for warmer climes and
extra-long work hours.
Still, counties and cities had granted at least 1,119 temporary
permits by late January, according to the Florida Department of
Professional Regulation. Even with the help, Munnell estimates that
some 2004-hurricane-related roof repairs won't be finished until
mid-2006. As the ubiquitous blue tarps in Charlotte, Escambia, and
other hard-hit counties slowly disappear, the next issue
surrounding the out-of-state roofers may be what happens when
customers discover flaws with their new roofs.
"If there are workmanship problems and they're [the roofers] from
Texas, they're not coming back," Munnell notes. His organization
failed in its bid to require all out-of-state roofers to work as
subcontractors to Florida roofers, a change he says would increase
homeowner cost but also put local roofers on the hook for repairs.
Building expert joins post-storm
Two hours after Hurricane Ivan made landfall, a Coast Guard HH-60
Jayhawk helicopter lifted off to do the first airborne
reconnaissance of the Florida Panhandle coast. Among those on
board: Forensics engineer Bill Bracken.
Bracken is Florida's lead Federal Emergency Management
Agency-qualified structures specialist. His primary job: Size up
damaged or destroyed structures and advise firefighters and rescue
workers before they attempt entry. Hired by the state during major
emergencies, Bracken and four colleagues joined rescue swimmers,
firefighters, and other first responders immediately after
hurricanes Charley, Frances, Ivan, and Jeanne.
Engineers joined first responders in the search for missing persons
in homes destroyed by Hurricane Ivan near Pensacola,
Forensic engineering typically values careful consideration over
quick judgment calls. But Bracken, president of Tampa-based Bracken
Engineering, said he's trained to give immediate advice after
examining cracking or listing buildings — making the call on
whether the building "is in a state of equilibrium or of imminent
"Our role is to do a very rapid assessment, because in our absence
these firemen are going to rush in there," he explained.
The engineers are also expected to put their expertise to use in
the air. Jostled by 60-knot crosswinds from Ivan's feeder bands,
Bracken flew from near Pensacola, Fla., to Mobile, Ala., on
September 16, 2004. Among the first to spot the collapsed
oceanfront condos that are among Ivan's most enduring images, he
helped direct ground-based rescue teams past obstacles such as
downed bridges to where they were needed most.
Last year's four hurricanes are thought to have left at least 100
Floridians dead. Bracken may well have helped keep that number from
rising any higher. In February, the Florida Fire Chiefs'
Association awarded him Search and Rescue Responder of the Year
— making him the first forensic engineer to receive the
award. — A.H.