Edited by Ted
Deck Collapse Injures Scores
Soil Tests Required in Upstate New York
Trench Work Poses On-Going Hazard
Light Heavyweight: New Concrete Lets In the
FEMA Will Pay to Move Threatened
Painting Brown-Coat Stucco Causing Problems
in the Southwest
Ledger splits from faulty lag screw installation
Summer seldom passes without at least one report of a
serious structural failure of an outdoor deck, with large
numbers of casualties. Unfortunately, the summer of 2004 is no
exception: On July 30, a wood deck collapsed suddenly under the
weight of a party crowd at the Diamond Horseshoe Casino in
Polson, Mont., injuring dozens of people and sending four with
life-threatening injuries to hospitals by helicopter.
Area hospitals were flooded with injured, according to a report
by Sherry Devlin of the Missoulian newspaper. "In addition to
the four life-threatening injuries, three others were
classified as critical and 27 as non-life-threatening by EMTs
on the scene," writes Devlin. "At least 20 other people arrived
at Polson's St. Joseph Hospital in cars and pickup trucks soon
after the accident, and another 20 sought medical help during
the day on Saturday." Nurses set up a triage center on the St.
Joseph's hospital lawn to handle the overflow, according to
Devlin's report. Emergency crews responded from five nearby
towns, some ambulances driving an hour over rural roads to
reach the scene.
Lag screws and fragments of the split
ledger board remain attached to the building, and the mostly
intact deck lies on the ground below, in these photos taken the
morning after the structure's sudden collapse sent dozens of
injured to the hospital.
surprisingly, the Montana collapse was traced to a failure of
the connection point between the deck and the building. Hired
by the city of Polson to investigate, architect Paul Bishop of
Building Solutions LLC, reported that the deck's untreated
Douglas fir ledger "failed downward and outward as a result of
vertical loading well below the maximum allowed by the building
"My conclusions were threefold," Bishop told JLC in a telephone
interview. "The initial problem was that the ledger was
attached directly to the siding with no weather protection.
That allowed moisture to get between it and the building, and
it began to rot. The second issue was that the lag screws were
too few and far between, and they were driven through the
ledger with a rotary hammer rather than through pre-drilled
holes, which induced a splitting force. And then, all of the
screws were in exactly the same plane, so that the splitting
force was aligned along the entire 57 feet of ledger. The straw
that broke the camel's back was that the builder used 2x8 joist
hangers on a 2x12, so that all of the weight was distributed to
that ledger below that plane of lag bolts."
The deck collapsed after midnight Friday night, and Bishop
inspected the wreckage the next morning with a group of town
officials. "When I got there, I saw that the ledger had
basically unzipped itself," he says. "There were fragments of
ledger on the building, and the rest of the ledger remained
securely fastened to the deck, which remained intact, on the
concrete patio below." Two loud cracking noises, heard by
people on the deck just before the collapse, must have been the
sound of the ledger splitting, says Bishop: "I didn't see
anything else broken."
A morning-after photo shows the bottom
half of the split ledger board still attached to the otherwise
intact deck assembly.
Evidence removal. Paul Bishop
is the only architect in the county surrounding Polson. "And I
knew that the only engineer in the county was on vacation," he
said. "That's why I offered my services to the town on Saturday
morning." Bishop made his inspection barely in time to view the
scene undisturbed: By Saturday afternoon, the building owner
had allegedly hired a local firm to cut the wreckage up and
take it to the landfill. Police have reportedly opened a
criminal investigation, centering in part on "exfoliation"
(illegal removal) of evidence. At least one victim has already
filed a civil lawsuit. "There will probably be condos there
instead of a casino, in the end," said one town official.
Bishop says, "My firm has been hired to go to the landfill and
retrieve every scrap of the deck and put it into storage.
Ultimately it may be reconstructed, the way they put crashed
airplanes together." At the bottom of the pile of debris, he
said, was a significant find: "We got some pieces of split
ledger that showed weathering around the fasteners. Maybe at
some previous event where there were a lot of people on the
deck, the ledger split partially, and then water was able to
get in there and discolor the split. And then there were some
areas of raw wood where it really split when it collapsed. But
the thing had been trying to tear itself apart for some
Lag screws driven through the centerline
of the deck ledger created a critical split line in the member,
which was loaded below that line by undersized joist hangers,
according to an architect's report. When the ledger suddenly
split, the deck toppled out and down, injuring dozens of
In the immediate aftermath of the collapse, a lawyer for the
building owner had pointed to the fact that the deck was
inspected in recent years by fire officials, and passed. But
Bishop says those inspections had no relation to the deck's
structural integrity. "The fire department inspects for things
like if their fire extinguishers are charged, if their
emergency and exit lights function, if their exits weren't
blocked by keno machines — it was a very cursory kind of
a thing." The fire inspectors aren't trained to evaluate
structure, he said.
Allowable load vs. occupancy.
The misunderstanding points up a common source of confusion in
reporting about deck failures: the difference between a deck's
allowable occupant load and its required structural bearing
capacity. The two unrelated issues are addressed in different
chapters of the code: Occupancy is part of the safe egress
requirements, while deck bearing capacity is a structural
Bishop and Polson Fire Chief Thomas Maloney had to thrash the
issues out as they probed the Polson failure. "It took a little
time for him to explain it to me," says Maloney. "He kept
telling me that by code, the deck should support more people
than could fit onto it. And I kept saying, 'I don't care if you
could park ten Abrams M-1 tanks up there — they aren't
allowed to have that many people on it."
The issue of whether the deck had more people on it than its
permitted occupancy load is debatable, but irrelevant, says
Bishop. "A lot more people wanted to be outside on the deck
that night than wanted to be inside the building, so it was
loaded. I don't think it was over the code max, but the bar
owner can say that the number of people made it fail, and that
is true in a sense. But by code it should hold more than that
weight. And given enough time, it could have collapsed under
two people some day, the way it was deteriorating and coming
Bishop draws lessons from the catastrophe. "The way the
building code is structured," he points out, "nobody is going
to come back and re-inspect that deck for you over the years.
You have one chance to do it right — when it is first
built and inspected. The contractor and the carpenters and the
inspectors — you need to have a conscience about what you
are doing. It is so simple to do it right, but the consequences
of doing it wrong are so grave."
"A lot of people, especially in rural areas, moan and complain
about the building code," Bishop comments. "'Oh, the building
code, the building inspector, that miserable son of a bitch.'
But that building code is the basic threshold standard for
safety, as far as I am concerned. We have absolutely nothing
else to protect us, even from ourselves, but that building
code. And when guys just flout it — I mean, this
particular deck was something you wouldn't want on the back of
a trailer house."
The disaster could have been far worse, he observes: "That deck
was filled with young people, athletes who were in town for a
basketball tournament. Even so, there were some hideous
injuries. If it had been a wedding party, with elderly people,
a lot of them would not have survived."
Soil Tests Required in Upstate
New York Community
Building officials in Amherst, N.Y., where soil and
foundation problems have attracted widespread press attention
(see "Foundation Flaws Spark Buffalo Brouhaha,"
In the News
8/03), are now requiring a soil test for every new house
project north of the Onondaga Escarpment, a geologic feature
that marks the boundary of the area's deep clay deposits,
reports the Buffalo News. A town rule requiring rebar in all
foundations and footings was shot down last year by a state
building code review board, but the town's latest move is
consistent with International Residential Code provisions
allowing local authorities to mandate soil testing where
conditions warrant. Where testing reveals problematic soil
types, permit applications will have to include an architect's
or engineer's letter stating that the foundation design is
appropriate for site conditions.
Trench Work Poses On-Going
Working in a trench is one of the most dangerous jobs on a
construction site. Federal statistics show 542 worker deaths
associated with excavation or trenching between 1992 and 2001
(the Feds say the true number is higher). Construction laborers
were the most frequent victims — 236 laborers died in
digging accidents during the period — but other trades
also suffered: 42 plumbers, 38 excavator operators, and 27 con-
struction supervisors were counted among the dead.
By type of employer, the largest class of victims — 141
— worked for excavating firms, while 131 were water,
sewer, or other utility workers, and 59 worked for plumbing or
hvac contractors. Only 19 of the dead were employed by
homebuilders. But anecdotal evidence shows that many of the
laborers who lost their lives digging were working on homes at
the time, for foundation contractors or other subs on the
Things haven't changed in the new century, judging by recent
press reports. The summer's rushed construction pace and heavy
rains that soften the earth have contributed to a series of
fatal accidents that made local papers. In one case,
40-year-old worker Gary Dillon died in a 4-foot-deep sewer
trench for a new development in Newark, Ohio, on July 27,
according to a Newark Advocate report.
Concrete workers nearby rushed to free Dillon from the earth,
but their efforts were in vain. "We found him and pulled his
head up, and he still had a pulse, and we kept digging and
digging, trying to yank him out of there," one told a reporter.
"We couldn't get him out, and his pulse stopped somewhere
The Pipe Man (short for "pipe
manipulator") robotic pipe-laying device could prevent
dozens of deaths a year by avoiding the need for sewer
and utility workers to work in trenches.
Trench collapses account for the majority of excavation
deaths in recent government statistics. Although OSHA safety
requirements for sloping or shoring trench sides are effective
the agency says deaths declined by 60% after rules were
tightened in 1989 — the precautions are still widely
omitted. In the case of the Newark accident that killed Gary
Dillon, the rules might not have applied in any case: The
4-foot-deep trench that buried Dillon did not reach the safety
rule's 5-foot threshold.
But even a shallow trench can kill. One reason trench risks are
taken lightly in the field may be that people underestimate
soil's deadly nature. As Small Flows Quarterly pointed out last
year, "A cubic yard of trench soil weighs 2,700 pounds, about
the same as a mid-sized automobile. A person buried under only
a couple of feet of soil would experience enough pressure on
the chest to prevent the lungs from expanding. Suffocation
would occur within about three minutes." The force of falling
earth can also crush organs and break bones, and the crushing
of large and small blood vessels and cells releases toxins into
the body. Victims who don't suffocate often die of internal
bleeding or shock.
The Fall 2003 Small Flows article introduced a new technology
that could sharply reduce trench risks, if adopted. The robotic
"Pipe Man" device developed by Leonhard Bernold and colleagues
at the North Carolina State University's Construction
Automation and Robotics Laboratory
(www2.ncsu.edu/ncsu/CIL/CARL) eliminates the
need for workers to hand-lay pipe in the trench. In tests,
Bernold says, the device was faster and cheaper than
traditional methods. But he says commercialization is held up
by a lack of funding for final refinements.
More information on trench safety is available at
Light Heavyweight: New
Concrete Lets In the Sun
For a material that dates back to Roman times, concrete is
surprisingly able to throw the world a few new twists. In the
new "Liquid Stone" exhibition at the National Building Museum
in Washington, D.C., architects and inventors are putting
concrete through a few paces designed to amaze and amuse. One
standout: translucent concrete that uses glass fibers in the
mix to allow the passage of light.
Glass fibers in
the mix let LiTraCon concrete blocks achieve
translucency, opening up a new set of options for
daylighting and night-time illumination in concrete
Hungarian architect Aron Losonczi developed the new material
several years ago while studying in Stockholm, Sweden, after
being inspired by a glass-and-concrete sculpture he had seen in
Budapest, Hungary. But the material has potential uses that are
as practical as they are artistic: Andreas Bittis, an executive
at LiTraCon, a German company that plans to bring the product
to market within the year, suggested that translucent concrete
could be used to bring natural light into subway stations, or
to provide fire egress structures that would have day-lit
visibility even if power failed in an emergency. An early
demonstration project uses LiTraCon blocks to make a sidewalk
that glows at night with artificial light; Bittis suggests that
the same product could create lighted speed bumps or pedestrian
crosswalks for streets.
The "Liquid Stone" exhibit is free to the public, and will be
open until January 23, 2005. More information is available at
FEMA Will Pay to Move
In a rare decision, the Federal Emergency Management Agency
(FEMA) has agreed to help the owners of a North Carolina
beachfront condominium project cover the cost of moving the
building back from its eroding beach frontage. In July, FEMA
announced a $3.6 million grant to the town of Kure Beach to
help the building's owners tear it down and rebuild it on the
other side of U.S. Highway 421.
Known as "The Riggings," the wood-frame clapboarded multifamily
building has been threatened by encroaching waves for years.
Federal erosion-control programs are active all around the
site, but because of environmental restrictions, The Riggings'
own particular beach isn't included. On the northern side, the
U.S. Army Corps of Engineers runs a "beach nourishment" project
that feeds sand onto the eroding beach to keep it from
disappearing. To the south sits a rock breakwater more than
half a mile long (technically illegal, but allowed as an
exception because it protects parts of historic Fort Fisher
from washing away). But near The Riggings, rare "coquina rock"
outcroppings form a critical habitat that the Corps isn't
allowed to dump sand on; the Riggins has been relying on giant
sandbags near the base of the building as a temporary
protection since 1985, when an older rock wall failed.
Public interest groups have questioned the expense of a federal
relocation program that leaves the building still in an exposed
location. But residents say it's justified because their
problem is at least partly the result of other federal efforts
Stucco Causing Problems in the Southwest
As if the stucco industry needed another black eye in the
wake of the much-publicized latent defect issues surrounding
EIFS a few years ago, suppliers and contractors in some
Southwest markets are witnessing a public backlash against the
material as moisture problems arise from improperly painted
exterior stucco on new homes. "It's become a lucrative repair
business for me, but the [stucco] industry is suffering," says
Steve Scutt, owner of Scutt Plastering in Albuquerque, N. Mex.
"I've seen problems on homes that are just completed to those
that are four years old."
The problem, says Scutt and others, is that builders at the
lower end of the market aren't waiting long enough for a single
brown coat of stucco to properly cure before applying a
non-porous latex or elastomeric paint. As a result, the coating
traps moisture in the wall, hindering the stucco's ability to
properly cure and reduce its pH level to mitigate efflorescence
and other problems on the surface. "The brown coat needs to
cure at least 28 days so the pH can drop [to neutral]," says
Richard Owens, sales director for El Rey Stucco in Albuquerque,
a supplier to several Southwest markets.
Painted stucco has replaced pigmented
applications in some Southwest markets, but suppliers worry
that builders aren't allowing the cladding to cure properly and
possibly causing latent moisture problems.
Moisture generated from evaporative cooling systems, an
inexpensive air-conditioning alternative in the Southwest, as
well as building code and warranty issues resulting from
one-coat applications, add to the potential for failure,
callbacks, and maintenance issues.
Painting the textured brown coat of stucco (as opposed to
applying a pigmented finish layer) has become standard practice
in affordable housing projects in markets such as Las Vegas and
parts of Southern California, saving builders a few hundred
dollars per house on the stucco contract and making it easier
to match surface repairs to the original color of the
But as the trend migrates to Arizona and New Mexico, climate
issues in those markets — especially seasonal and even
daily temperature swings — have caused problems ranging
from excessive stucco cracking and spalling to latent moisture
issues, including mold growth and structural degradation. "It's
a cardinal sin to paint stucco in this part of the country,"
says Scutt, in light of the freeze-thaw cycles of the
Albuquerque climate. "There's been a big influx of builders
coming in with no clue about our market."
It's also critical to get a proper mix and thickness; ICC-ES
specifies a 1/2-inch thickness for one-coat (or base-only)
stucco applications as a comparable alternative to a three-coat
application. In addition, a proper base coat mix is essential
to lasting performance. "The mixer is the most important guy
when it comes to stucco quality and its ability to take paint,"
says Scutt. "Too much sand, and it'll never cure
While no stucco-specific paint exists, coating manufacturers
recommend that both traditional or synthetic stucco surfaces be
clean, dry, and dull and have a neutral pH level prior to
painting with two coats of a high-quality exterior latex or
elastomeric coating, the latter of which helps bridge cracks.
Walls with a high pH level need an exterior acrylic masonry
primer that is high in alkali and resistant to efflorescence
prior to the finish application. "Moisture leaks and high pH
are typically the reasons for stucco failures," says Steve
Revnew, director of architectural marketing at The
Sherwin-Williams Company in Columbus, Ohio.
— Rich Binsacca is a freelance
writer in Boise, Idaho.
OffcutsBuilders and county officials in greater Cincinnati,
Ohio, are battling over proposals to limit the expansion of
housing developments around the city,
according to the
Cincinnati Post. Warren County Commissioner Mike Kilburn is
proposing to put all subdivision permits on hold while the
county finds out whether it can charge a $10,000-per-house
impact fee for street and school construction costs. But
Cincinnati HBA president Timothy Hensley says new home
construction pays back more than it costs localities within
five years, and that with the region "crying for construction,"
talk of a building moratorium is "scary."
The Colorado Supreme Court says developer W.O. Brisben
must pay the court costs of Air Force Captain Eric
Krystkowiak after losing a lawsuit for damages based
on the captain's outspoken opposition to a Brisben project,
according to a story in the Rocky Mountain News. Colorado law
provides for citizens to recover court costs if they defeat a
lawsuit brought in retaliation for democratic participation.
Brisben had argued that Krystkowiak broke a contract when he
spoke against Brisben's application to build apartments near
his condo (Krystkowiak had joined the condo association's
effort to stop the apartment project, but left the group when
it struck a deal with Brisben). However, the high court ruled
that the association's decision could not abridge Krystkowiak's
constitutionally guaranteed freedom of speech.Back to