Setting a new precedent for wind codes,
Florida focuses on reroofing
Under a new Florida law, any reroofing job performed in the state
of Florida must now include upgrades to the roof structure and a
peel-and-stick water barrier. These two rules, along with measures
to upgrade roof-to-wall connections and opening protection on some
homes, are intended to update the majority of the state's housing
stock. According to census figures, about 78% of Florida's homes
were built before 1992's Hurricane Andrew. The destruction from
that storm led to a building code change that is widely seen as an
effective standard for building hurricane-resistant homes.
Under a new Florida law, roof sheathing may need renailing, and
a secondary water barrier, such as 4-inch flashing tape, must be
installed before any existing home can be reroofed.
On Every Reroof
The "roofing mitigation rule," as the new law has been dubbed,
essentially requires roofers to nail off the sheathing with
ring-shank nails and apply peel-and-stick — either by taping
panel joints with 4-inch-wide flashing tape or by applying a
continuous SBS roofing membrane — prior to installing a new
roof on existing single-family homes.
There seems to be little argument about the nailing requirement.
"It's a no-brainer," urges Carolyn Ackerland, of Gary's Roofing
Service, based in Sarasota, Fla. "We see so many roofs that are
stapled down; it's not that big a deal to nail them off. This has
just become a standard part of what we do." The rule boils down to
making sure that plank sheathing has two 8d ring-shank nails in
every rafter or truss. If the roof has panel sheathing instead, it
must be nailed off every 6 inches with 8d ring-shank nails.
Homes valued at $300,000 or more may need improvements to the
roof-to-wall connections prior to reroofing. This work must be done
by a licensed general contractor, not a licensed roofer, so
companies like Gary's Roofing Service, which holds both licenses,
will be in the best position to benefit from the new
Ackerland sees value in the peel-and-stick rule, too. Taping the
seams proves more labor intensive than applying a continuous
membrane, she says, but it also allows a roofer to strip back to a
clean deck on the next reroof. "There are always trade-offs,"
Ackerland acknowledges. "We do our best to educate the homeowners
about the options. But some type of secondary water barrier is
needed. Hurricane Charley opened our eyes to that."
For High-End Homes
Besides the two basic reroofing rules, additional mandates apply to
homes in windborne-debris regions that are insured at $300,000 or
more. In this case, the roof-wall connections must be reinforced
with uplift hardware and gable-end bracing. The rule defines the
amount of reinforcing not only in terms of uplift resistance but in
monetary terms as well: a minimum of 15% of the cost of the reroof
must be applied to strengthening the roof-to-wall connections. This
means that if a reroof costs $10,000, at least $1,500 must be spent
on reinforcing the roof-to-wall connections. Since this amount may
not be enough to reinforce all of the roof-to-wall connections on
the home, the law assigns priority to strengthening the gabled
sections of the roof above hipped sections and to strengthening
framing connections near the corners of the roof over connections
in the middle of wall sections.
As first adopted by the Florida Building Commission, the new law
was written to go into effect on October 1, 2007. However,
legislative maneuvers prevented the ruling from being filed with
the Florida State Department, delaying the effective date to
January 1, 2008. Parties seeking the delay argue that the new law
imposes new inspection procedures to verify the sheathing nailing
that have yet to be established. Questions also remain about whose
responsibility it is to establish the value of a home during
permitting, and how contractors are to choose which parts of the
structure must be improved. Citing one example of the confusion the
law is bound to create, Steve Munnell, executive director of the
Florida Roofing, Sheet Metal and Air Conditioning Contractors
Association, writes: "If a residence has four roof ends and the
total cost to improve all four would be 20% of the total cost of
reroofing, should the consumer do only two or three? … If
so, how does the consumer or contractor select which two or three
should be improved?"
While the details have yet to be ironed out, the law will assuredly
provide increased opportunities for contractors, although which
contractors has also been a sticking point. Roofers are restricted
from installing the uplift connectors required to improve the
roof-to-wall connection, providing more opportunity for licensed
general contractors than for licensed roofers. — Clayton
Debating Climate Change
No simple answers in the search for causes
The costliest hurricane in history. Atlanta reduced to 90-day
supply of freshwater. A Florida drought so severe, Lake Okeechobee
Few would argue that the Southeast has experienced its share of
major weather-related catastrophes in recent years: the region is
in its worst drought since record-keeping began in 1895.
But scientists remain uncertain whether Hurricane Katrina, the
widespread Florida fires last spring, or the worsening drought
parching Georgia and neighboring mid-Atlantic states can be blamed
squarely on global climate change.
"None of these can be ironclad links to climate change," says
Stephen Mulkey, a professor of botany at the University of Florida
who recently served as science advisor on global warming to the
Century Commission for a Sustainable Florida. "But they are
indicative of the kind of pattern we expect."
While much of the Southeast experiences severe drought,
elsewhere marshlands have been swamped by rising sea levels. The
exact reasons such changes have occurred are often numerous, making
it tough to pinpoint causes. But evidence is mounting that the
changes are global and likely to get worse.
Global vs. Local Impacts
The Intergovernmental Panel on Climate Change, the United Nations
panel of 2,000 climate experts, in mid-November warned of "abrupt
and irreversible" impacts from global warming. Although the IPCC
has been at its most dire predicting future events, the report
cited many changes already underway, including retreating glaciers,
thawing permafrost, and snow loss in alpine areas. It was hardly
the first to note big events sweeping northern latitudes: this
summer, for example, scientists reported that the Arctic had lost a
third of its summer sea ice since measurements began 30 years ago,
and that the loss had speeded considerably since 2005.
But, at least for now, many changes to weather or natural systems
in warmer regions of the U.S. and Southeast are either less
dramatic or, as scientists sometimes put it, within the range of
historic climatic variation. On other fronts, such as whether
climate change is increasing the severity of hurricanes, the debate
Mulkey says local trends muddy the picture further by either
masking or counteracting the effects of overall climate
Eleven of the last twelve years rank among the twelve warmest years
in the historical record of global surface temperature, according
to the IPCC. But one recent study found that Las Vegas has cooled
in recent years, thanks to the efforts by residents in planting and
irrigating trees and shrubs, Mulkey says. Florida's irrigated
agricultural areas have seen a slight cooling effect for similar
reasons, he says. Historically, Florida freezes have advanced
farther and farther south, as farming and development have uprooted
the state's heat-trapping wetlands.
Of current impacts of climate change on the Southeast, "I wouldn't
use the word ‘minor,' " Mulkey says. "I would use the words
‘obscured' or ‘camouflaged.' "
That said, a handful of studies have documented current impacts.
Mulkey's colleagues at UF have found that palm trees are dying on
Florida's west coast as a result of climate-change-driven sea-level
rise. Although levels globally have risen only 3.1 millimeters, or
.12 inches, annually since 1993 — a far cry from the IPCC's
projected rise of as much as a half meter by 2100 — local
rise, combined with increased tidal flooding, appeared to be severe
enough to kill the most seaward palms in the low-lying study area,
according to research published this year in the journal Global
Change Biology. The trend is accelerating: of 88 large, mature
palms that died at the North Florida site between 1992 and 2005,
66%, or 58, died since 2000, the researchers say.
"With expected increases in the rate of sea-level rise coupled with
increasing drought frequencies resulting from global climate
change, accelerated rates of coastal forests disappearance are
likely and may already be evident," botany Professor Francis "Jack"
Putz and four other authors concluded.
Elsewhere in Florida, widespread coral bleaching in the Florida
Keys may be tied to hikes in ocean temperatures. Saltwater
intrusion from sea-level rise has swamped some low-lying sources of
the Keys' freshwater, says the U.S. General Accountability
Other states also have experienced changes. Maryland's Chesapeake
Bay and coastal Louisiana are among states that have lost thousands
of acres of marshes to open water, though separating the effects of
sea-level rise from those of development, land subsidence, oil
production, and other local changes is problematic. Some species of
ducks have stopped migrating to South Carolina because of warming
temperatures in their northern summer grounds, according to news
accounts. And trees in North Carolina and elsewhere have suffered
from insect infestations tied to prolonged drought.
"It's subtle and small right now," Mulkey notes. "But to ignore
what the huge majority of peer-reviewed literature is saying is
foolhardy." — Aaron Hoover