Edited by Ted
Cushman
CONTENTS:
Fatal Chicago Porch Collapse Highlights
Flimsy Connections
Housewrap Aims to Drain Walls
New Wood Treatments May Be More
Corrosive
Polka Dot Paint Job Makes Protest
Point
Offcuts
Fatal Chicago Porch Collapse
Highlights Flimsy Connections
Chicago officials were quick to blame heedless crowding for
the three-decker porch collapse that killed 13 partygoers in
the city's Lincoln Park district on June 29. "It is a tragic
case of overloading the back porches," Chicago Fire
Commissioner James Joyce told CNN. The Reuters news agency
quoted Joyce as saying, "It appears to be a case of too many
people in a small space." City Emergency Management Director
Cortez Trotter told the press, "Common sense should prevail at
some point."
But in the following days, the city sued the building owner
and the contractor who built the porch, charging that the porch
was unsafe and was built without a permit. In turn, attorneys
for the estates of people killed in the catastrophe have sued
the city as well as the owners and builders, saying Chicago
fell short of its duty to inspect properties and regulate
construction. Suits focused immediately on undersized
joists.
Seeking clues to the catastrophe's
cause, attorneys and forensic experts are poring over dozens of
blurry digital images released by the City of Chicago. The
images show some of the construction details. At top left, the
main posts away from the house are still in place, supporting
the roof. At top right, a ledger board intended to carry joists
at the end next to the house has separated from brick exterior.
The ledger board was installed in pieces and fastened into the
wall face with bolts (bottom left). View of the ground level
(bottom right) shows concrete post piers. Victims on the
ground- and second-floor levels were crushed by the weight of
falling upper stories.
At least one expert view runs sharply counter to the
off-the-cuff comments of city officials about "overloading."
Frank Woeste, P.E., Ph.D., a professor of engineering at
Virginia Tech and one of the authors of the heavily researched
new Manual for the Inspection of Residential Wood Decks and
Balconies (available in October from the Forest Products
Society, 608/231-1361), told JLC, "From what I could see from
TV reports, it is hard to believe that porch was overloaded.
The code says the allowable live load is 40 pounds per square
foot. The average person weighs 160 pounds, so that deck should
support one person for every 4 square feet — a 12 by 20
area should safely support 60 people." Early eyewitness reports
estimated the crowd of partygoers at 70 people sharing all
three levels of the three-story porch structure and its
staircases.
"I don't know what that fire chief based his statement on, or
why the media kept repeating it," said Woeste. "But if you know
the code and take 30 seconds to do the math, you would think
this deck should not have failed."
Woeste
was critical of press coverage of the collapse, saying, "All
day long, the television rebroadcast that fire official saying
the deck was overloaded. That gives people all over the country
the idea, 'I don't have to worry about my deck — those
fools in Chicago just had too many people out there.'" In fact,
says Woeste, most decks are not built strong enough to handle
allowable loads. "When we went out and surveyed decks for our
manual," he says, "we didn't find one that was totally code
compliant. Not one."
Collapses are common. Deck
failures occur every year across the country. Collapses that
cause mass casualties at Independence Day celebrations or
special occasions such as weddings and birthdays tend to get
the most press, but decks often fail under lighter loads. Two
weeks before Chicago's tragic disaster, for instance, four
porches collapsed at once on a row house building in Camden,
N.J., under no unusual load at all (the story was not widely
reported).
Failed ledger connection is visible in
photo released by the Chicago building department to justify
removing the porch wreckage as a hazard. The ledger board was
not continuous and was attached by bolts driven into mortar
joints in the brick exterior, witnesses said.
Like Woeste's research team, Chicago city inspectors found
widespread deficiencies in their belated inspections of 700
decks and porches after the tragedy. Officials cited at least
545 structures for violations, and condemned 70 outright.
Ounces of prevention. But Chicago policymakers
continued to focus on overloading in discussions of
post-disaster reforms. Some proposed to solve the problem with
signage: State lawmakers Susan Garrett and John Fritchey
announced plans to introduce a bill requiring signs limiting
porch capacity to be posted near porch entrances, while Chicago
Alderman Edward Burke brought a similar measure to the city
council.
Other aldermen wanted to reemphasize the distinction between a
"deck" and a "porch," and limit "porch" use to smaller groups,
although none had any immediate plan for making the
case-by-case distinction or enforcing any limits on the size of
gatherings.
But some city leaders began to consider how to make sure that
decks were built to support the numbers of people that can
actually fit onto them.
John Roberson, executive director of the city's newly created
Department of Construction and Permits, proposed that the city
require an architect's plan before granting a permit to repair
or replace a porch. And Mayor Richard Daley's office revived an
idea to require licensing for general contractors.
But the mayor dismissed calls to increase staffing at the
city's building department, saying, "I can't hire 25,000
inspectors. Everybody would go bankrupt. You would be paying
huge property taxes, and people don't like to pay property
taxes." And building owners and deck builders continue to
resist reforms, citing the problem of added costs and delays.
Meanwhile, the city is talking about a "ghost payroll" scandal
at the building department involving an inspector who filed
bogus inspection reports for buildings he never visited.
Paying the price. Whether or
not Chicago's building owners, contractors, and city government
want to shoulder the responsibility for safe construction in
the future, lawyers intend to force it on them retroactively in
the case of June's tragedy. And if precedent is a guide, the
argument of "overloading" is likely to prove a weak one for the
defense. On July 29, for instance, a Memphis court awarded $1
million to seven people injured (not killed) in a deck collapse
at a 1999 graduation party — despite defense arguments
that 16 people on the 9x34-foot deck was too large a
group.
Do the math. Concerned
builders needn't wait for the dust to settle to take action. As
Woeste's observations above make clear, many decks are
underbuilt and survive only because they rarely if ever see
full code design loads. If you build decks or porches, apply
the code's 40-pound live load to the entire area and consider
whether the structure is truly up to the task. It's relatively
easy to choose joist size and spacing, but don't overlook
ledger attachment (see
"Attaching Deck
Ledgers," 8/03) and post stability, especially as the deck
gets higher. Revisit and inspect past jobs; if they're not up
to snuff, reinforce the structures. If you have any doubts,
call an engineer.
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Housewrap Aims to
Drain Walls
Housewraps are intended as "weather resistive" materials
that block water as well as wind. But they defend best against
rain when there's an air space between the cladding and the
wrap; when water is held against the wrap by tightly nailed
siding, wraps may leak, especially if the water contains
surfactants from paint or extractive compounds from wood.
This is the rationale behind "water-managed" or "rainscreen"
wall designs, which typically call for vertical strapping over
the housewrap, with siding nailed to the strapping. But
GreenGuard RainDrop, a new product from Pactiv, Inc., aims to
cut out the middleman. Vertical cords worked into the new
housewrap's woven plastic are thicker than the rest of the
sheet and don't compress when siding is nailed over them. The
result, claims the company, is an array of channels big enough
to break the capillary bond and allow water to drain.
A new housewrap product called RainDrop
has heavy cords worked into its plastic weave to allow free
drainage of water, even under tightly nailed wood or
fiber-cement siding. The wrap should be applied with cords
aligned vertically.
Company marketing exec Dan Partrich says, "In tests, we
sandwich the stuff between two layers of Plexiglass, clamp it
down, and pour water in the top. Water scoots right through,
and air can also run up the back side."
The wrap won't work directly under stucco, says Partrich,
because the cement will bond to it. It might be effective with
a layer of regular paper between the stucco and the RainDrop
wrap, he notes, but Pactiv has not tested that application.
"Eventually, we're going to have a wet stucco wrap anyway," he
says. "Where this really works best is under fiber cement or
wood clapboards. Of course, you have to remember to put it on
with the cords in the up-and-down direction."
Partrich says housewrap prices fall into tiers, with premium
wraps like DuPont's Tyvek and Pactiv's Ultra Wrap at the top.
Pactiv's Value Wrap is priced at the bottom to compete with
regular building papers, and their Classic Wrap is somewhere in
the middle. "RainDrop will come in higher than our Classic Wrap
and lower than our Ultra Wrap," says Partrich. For drainable
systems, however, it should offer significant savings compared
to the labor and material cost of nailing on strapping and
adapting windows, doors, and trim to the fattened walls.
For information on RainDrop, go to
www.green-guard.com.
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New Wood Treatments May Be More
Corrosive
Wood treaters and hanger manufacturers are circling warily
around an issue that makes the whole industry nervous: the
tendency of alternative preservative treatments including
alkaline copper quaternary (ACQ) and ammoniacal copper zinc
arsenate (ACZA) to eat through steel and galvanizing coatings
much faster than the chromated copper arsenate (CCA) formulas
they are replacing in the market. As treaters make the switch
from CCA to alternative formulas in January 2004, corrosion
questions will throw new uncertainty onto the field performance
of treated wood structures.
This galvanized base connector, placed
under a post treated with a nonarsenic ACQ formula, is rusting
after only a few months in service. Wood treating companies
continue to recommend either hot-dipped galvanized or
stainless-steel fasteners for use with wood treated with new
preservative formulas. But Simpson Strong-Tie execs say
extra-heavy galvanizing will be needed to protect connectors,
and they will not predict how long galvanized connectors will
hold up in service.
The issue is becoming contentious already. Simpson Strong-Tie
sales exec Mike Bugbee says, "The treating companies are upset
with me for even bringing it up." University experts we called
wouldn't talk openly about the issue, reluctant to jeopardize
connections with industry colleagues. But some test numbers
show that in the laboratory, ACQ corrodes steel about four
times faster than CCA does, and removes galvanizing coatings
twice as fast. In fact, one lab report found that ACQ-treated
wood attacked galvanized metal slightly faster than CCA
corroded the mild steel used for ordinary nails.
No one is sure what the lab numbers imply for treated-wood
structures in service, but hanger manufacturers like Simpson
Strong-Tie are plainly uneasy. Simpson has done more than 1,700
tests of various metals in contact with treated wood samples,
but the company's website is vague about what the tests
revealed; it says only that new formulations may corrode metals
at a different rate than the old ones did. Simpson advises
using hot-dipped galvanized products at a minimum and stainless
steel where possible, but warns against mixing the two, which
can cause a reaction that will degrade the galvanized coating.
With ACZA (which contains both zinc and arsenic but is not
being phased out), Simpson recommends only stainless
steel.
Other factors being equal, Simpson points out, heavier
galvanizing coats last longer. The company provides a line of
heavy-duty galvanized products as well as some stainless-steel
items. But citing the "many variables involved," Simpson won't
recommend any specific galvanized coating or provide an
estimated service life for any hangers or fasteners.
Meanwhile, wood treaters are hustling to reduce the
corrosiveness of their formulas. In the case of ACQ, chlorine
in the salt solution used to carry the active ingredients may
be replaced with a less corrosive carbonate. But EPA approval
of any new formulas takes time. For now, say experts, builders
should turn to the wood manufacturer for guidance on fastener
choice.
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Polka Dot Paint Job Makes
Protest Point
Homeowner Stan Pike was frustrated this spring when the
Historic Preservation Commission in Avondale Estates, Ga.,
wouldn't approve his plans for a round porch on his newly
purchased house. Pike thought the decision was a bit arbitrary
— his 1950s-era home wasn't historic itself (just located
within the historic district), and it already had a round room
on one end.
So Pike decided to exercise his own arbitrary powers as a
homeowner. The commission couldn't stop him from painting the
building lime green with fluorescent purple polka dots —
so he did.
Some neighbors disapproved, but others expressed support, even
to the extent of adorning their own properties with purple dots
(although one couple used plastic cutouts).
After a brief moment of fame including an interview on NBC's
Today show, Pike won his appeal of the commission's
ruling and repainted his house a sedate off-white. Pike told
reporters he was glad he'd stood up on behalf of residents who
thought the preservation commission needed to unbend a little.
But town mayor John Lawson wasn't conceding any points of
principle. The commission had turned down only 4 of 114 plans
in 2 1/2 years, he said, and required changes in 20. Said
Lawson, "I think the numbers speak for themselves."
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Offcuts
North Carolina officials are studying options for "buffer
zones" to limit housing and commercial development around the
state's military facilities. State planners hope that
leaving the bases some open space to work with will help them
survive the Pentagon's next round of base closings. Large
installations such as Fort Bragg and Camp Lejeune generate jobs
and incomes for local communities, but encroachment of housing
and other civilian uses near the bases can reduce their value
to the military by restricting training activities such as
low-level flights and heavy equipment airdrops.
No one is entirely satisfied with Florida's newly passed
reform of the state workers' compensation law, according to
a report in the Palm Beach Post. The bill passed on a
party-line vote in the Republican-controlled legislature, but
the Post says even one Republican legislator labeled it
"horrible," while Senate President Jim King called sections of
it "problematic" and promised to study the issues further. The
new law limits attorney fees in comp cases, toughens fraud
provisions, and provides a backup system to insure contractors
with clean safety records who can't get coverage in the market.
Most of Florida's large comp carriers have left the state,
leaving many builders unable to get coverage at any
price.
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