Years Of Fixes Turned Leaky Kingdome Roof Into Sodden Disaster -- Flawed From The Start, Structure Fell Prey To Birds, Bad Weather, Bad Maintenance
Three months before it opened, the Kingdome roof began to leak. Nearly two decades later, it hasn't stopped.
High-priced consultants were called in and various fixes were attempted as the roof just seemed to get soggier and soggier. Some only made things worse:
-- A 1983 project to resurface and ventilate the roof had to be completely undone two years later when severe winter weather damaged the vent system and let in even more water.
-- In the late 1980s, desperate maintenance crews gouged crude channels in parts of the roof in hopes they would drain chronically soggy foam insulation. Those channels had to be filled and resealed later when they were discovered apparently letting in more water than they drained.
There is no clear accounting of how much money has been been spent on all the roofing consultants and contractors, on work time by county employees and administrators. The price tag for the newest reroofing project alone, started more than a year ago, is $6 million.
Through it all, through 18 years of football, baseball and soccer games, rock concerts, revivals and tractor pulls, 53 million people clicked through the Kingdome turnstiles with little idea of the problems overhead. Periodically there were reports of annoying drips or puddles.
Then on July 19, a half-hour before fans were admitted for a Mariners baseball game, four 26-pound, water-damaged ceiling tiles crashed into seats below.
An investigator, forensic engineer Robert LeFraugh, said: "I am surprised that only four tiles fell. It could have been 100 or all 850" in the immediate area.
A review of thousands of pages of Kingdome documents, memos and court records, plus interviews with engineers, architects, construction and maintenance officials, and consultants, suggests why LeFraugh was surprised.
The records show that from the very beginning, because of tight budgets, bad luck and oversights, the Kingdome wound up with a ceiling and roof that were destined to be trouble.
A CONTROVERSIAL PROJECT
The omens weren't good from the beginning. King County voters twice rejected proposals for a big-league ballpark before February 1968, when they OK'd a $40 million stadium bond issue (while rejecting rapid transit).
Lawsuits and public protests threatened to derail the project at every stage. When ground eventually was broken, protesters threw mud balls at dignitaries. A Seattle Times columnist predicted, three years before the stadium opened its doors, that the roof would leak.
Architects and engineers had first planned for a domed stadium at the Seattle Center. But voters rejected that site in a ballot initiative, and in 1971 the current site was chosen.
The designers were given just six months to redesign the stadium.
The new site, on unstable fill, was totally different from the old one on solid ground. It took 135 architects and engineers to beat the deadline. With only two days to spare, they designed a stadium that would rest on 1,800 pilings driven 60 feet into the ground and be covered by the longest-spanning thin-shelled concrete roof in the world.
Then there was the budget: $40 million at a time when other covered stadiums were costing three times as much.
"If you want a Cadillac, specify a Cadillac or you will get a Ford," construction magnate Howard S. Wright had warned. In King County, the public specified a Ford; the trick for designers was to avoid creating an Edsel.
In every detail, designers spared expense while emphasizing function. Stadium parts would serve dual purposes: Structural beams would double as architectural finishing; ceiling tiles would serve as form liners for the poured concrete roof slabs.
In the process, the designers produced a ceiling and roof cursed by several weaknesses:
-- Lack of moisture control.
Fans at a sporting event emit hundreds of gallons of water vapor from breathing, drinking and damp clothing. The ventilation system evacuates some of it, but a fair amount gets trapped in the ceiling, where it can damage tiles and insulation.
Experts say they can prevent moisture build-up two ways. One is with a vapor barrier that stops rising moisture near the inside surface of the roof. The other is with a roof porous enough to let the vapor out.
The Kingdome roof had neither attribute. Water vapor moved through the roof's four innermost layers - ceiling tiles, a paper liner, the concrete shell itself and a layer of insulating polyurethane foam sprayed over the concrete. Then the moisture was blocked by a relatively impermeable outer coating.
The roof couldn't breathe, said Adrian Jenkins, whose Tukwila company supplied the outer coating. Moisture condensed in the foam insulation and soaked back down into the ceiling tiles.
Unfortunately, a lot of polyurethane roofs were built that way at the time because installers didn't properly plan for "vapor drive," said Arizona State University engineering professor Dean Kashiwagi, a polyurethane expert.
-- Acoustical tiles were not bonded to the ceiling.
The rectangular tiles, known by the brand name Tectum and made of wood fiber and glue, were held in place by six metal clips along the edges. During construction, the tiles lined the bottom of the roof-section forms. Concrete was poured over the tiles, hardening around the clips. The system worked for 18 years, but once moisture weakened the tiles they delaminated and loosened from the clips.
LeFraugh, the forensic engineer, says the tiles might have stayed in place had the concrete been allowed to ooze into and bond with the surface of the tiles, which have a texture like Shredded Wheat cereal. But the tiles were installed with a backing of black felt paper, and that prevented an extra bond.
Before the roof was poured, Kingdome architect Dean Hardy asked the Tectum supplier whether it would be prudent to remove the paper lining. Dick Eide, the manufacturer's representative, replied, in a Jan. 18, 1974, letter, that the felt would protect the tiles from becoming stained during construction.
"National Gypsum Company (the manufacturer) does stand behind the use of clips alone and sees no gain in using Tectum without felt backing . . . The clips are sufficient in holding the Tectum," Eide wrote.
Eide, who went into the computer business a year later, says today he stands by his advice. He said stains would have taken away the "nice architectural look" of the tiles. He blames poor ceiling maintenance, not the lack of a concrete bond, for the falling tiles.
The paper might also have served as a much-needed vapor barrier had it been installed differently. But no one sealed the seams between tiles, effectively leaving 50 miles of cracks through which vapor could travel. During construction, the paper was further torn as steel was dragged across it and workers walked on the tiles with spiked shoes.
-- The Dome's reverse-arch sections work against the ceiling tiles. Unlike the arched ceiling of a cathedral, the 40 segments of the Kingdome roof arch downward into the building. This left the tiles bowed around the outside of a curve, rather than pressed edge-to-edge as they would be inside an arch. Bowed around the curve, natural tension would work to pull the tiles' edges away from the ceiling.
This was not a mistake, but a consequence of a design concept, known as the hyperbolic paraboloid, that allowed a lightweight roof, only 5 inches thick, that could span an eighth of a mile unsupported.
PROBLEMS FROM THE START
Seattle architect Fred Bassetti once said that "construction is largely a matter of figuring out who to blame." That aptly described the Kingdome project.
Towers collapsed at the beginning, and about halfway through the job - in November 1974 - the original contractor quit, complaining of design changes. There were less publicly obvious problems, too, such as those between carpenters and ironworkers.
Carpenter-foreman Gordon Rich recalls how his crews laid the Tectum tiles on the concrete forms only to see ironworkers walk on the metal clips, bending them down so they wouldn't stick into the concrete. Construction superintendent Vivan Godbey said he ordered carpenters to bend the tabs back up (and investigators say it appears to have worked).
But Rich said he never visited the Kingdome because he feared the tiles could fall. "And I told my friends to stay away, too."
During the summer of 1975, as polyurethane was sprayed on the outside roof, contractors needed dry weather. Instead, they got the rainiest August on record. September was dry, but October and November were very wet, and some polyurethane was permanently damaged because it was installed damp, court records show.
After that there was a steady drip, drip, drip of signs that all was not well with the roof.
Three months before opening ceremonies, a county contract officer wrote to the roofing contractor, Vertecs Corp. of Kirkland: ". . . there is evidence of water on the underside of the Tectum in several places . . . there should be no water leakage before the roof is considered substantially complete."
The roof was accepted, anyway, with a five-year warranty. The Dome opened to raves; soccer star Pele and evangelist Billy Graham packed it with the first 500,000 people. Though it had ultimately cost $70 million, the Dome was still built for half the cost of other covered stadiums. The financing worked: Dome revenues paid operating costs during most of its years, and the hotel-motel tax is on its way to retiring the original construction bonds by the year 2014.
Nevertheless, the roof leaked. Contractors tried patching it during the summer of 1976, but two years later some of the outer membrane had pulled away from the foam. Also, birds had pecked holes in the polyurethane insulation near the cupola - the cap atop the dome. And without proper maintenance, so much dirt was accumulating that trees and grass were sprouting in places. The contractor urged the county to clean it, but the job was difficult on such a steep slope.
Drip, drip, drip: On Sept. 28, 1981, stadium facilities manager Ron Cline wrote to Vertecs: "For your information, we did have two serious leaks during Sunday's Seahawk game."
With water trapped under the roof membrane and heated by the sun, a chemical reaction was breaking down the tiny bubbles inside the polyurethane. It turned the stuff into a sponge. In some places, the insulation was so squishy it felt like a waterbed. And, with age, the concrete roof shell was predictably cracking, forming paths for leaks.
In November, the county asked consulting architect David Nordfors to craft a solution. He hired William LeMasters, a former rodeo cowboy and deputy sheriff who studied engineering and became a roofing contractor. Feisty and opinionated, LeMasters had no college degree, but he did have ideas.
On his advice, Vertecs covered the roof with an additional membrane. It looked better, but it also trapped water inside the polyurethane. LeMasters designed a system to dry out the foam: Troughs were cut 50 feet up the outside surface of each roof section and vents were installed at either end.
In theory, moisture would escape through the covered troughs and out the vents. In practice only small sections of the roof, near the troughs, dried out. Then in November 1985, shortly after Tim Hill was elected county executive, avalanching snow and ice on the Kingdome roof sheared off many of the vents. During the thaw, water gushed into the polyurethane through the gaping holes. The $628,000 roofing job was a bust. The repairs cost even more.
Drip, drip, drip: On Nov. 3, 1986, Cline wrote: "Today we received calls regarding leaks in the roof at the following locations . . ."
In 1988, Kingdome workers discovered two loose ceiling tiles. They eventually fixed one, but reportedly couldn't reach the other.
On the outside, especially at the tension ring, where there are flat roof expanses, the polyurethane foam was obviously soggy. With little money to fix the roof, Kingdome maintenance supervisor John Hopkins told his staff to cut 32 trenches in the foam layer on the outer roof ring, presumably to help the water drain away. Kingdome facilities manager Donald Suiter was unaware of the impromptu project until he visited the roof and saw the bare concrete in 1989, according to court records.
"It was a bad idea," said Roger Tikka, a contractor who was paid $40,000 to repair the mistake. "It was crazy."
Hopkins, now living in eastern Washington, acknowledges cutting the trenches, but said, "I really don't want to talk about this."
Drip, drip, drip: An in-house Kingdome memo in August 1991 observed: "Old leak. Built up stalagmite on bench and floor. Wet and dripping, 30 sec. intervals."
In a meeting with several Kingdome officials that month, Michigan roofing consultant Ed Schreiber suggested that someone check the condition of the Tectum tiles. Product manuals warn that the Tectum tiles will degrade over time when continuously dampened.
Without a crane, though, the only way to examine the tiles was with binoculars. They looked fine, said Kingdome officials.
In January 1992, the ceiling tile manufacturer, Tectum Inc., told Schreiber that it could examine the tiles for $400 a day plus expenses. There's no indication Tectum inspectors were hired.
By now, Kingdome officials and their consultants were thinking about an ultimate roof repair. Schreiber proposed a metal roof over the old roof, but a County Council committee nixed the $10 million idea as too expensive.
The county was building a plastic pavilion next to the stadium, to accommodate trade shows, and that was eating up some of the money set aside for the roof.
At a May 18, 1992, meeting, Kingdome officials discussed a suggestion from Spokane consultant Thomas Gerard that the old, moisture-prone roof insulation be entirely removed. The officials noted that state law prohibits removing insulation without replacing it, but Kingdome architect Dick Gemperle suggested that the law, in this case, was illogical. "The county might have some influence with the state," he said, according to meeting notes.
In early 1993, at the request of the County Council, facilities managers from another county department took over the Kingdome roof project. During transition, the new team, headed by county official Jim Napolitano and Doug Haner, decided to strip off the old roof and replace it with a thin layer of specially treated cement and rubberized paint. The new coating would breathe, but it would have no insulation.
In an early test, workers cleaned a patch of the roof with high-pressure water washers.
THE LAST STRAW
In hindsight, it was the beginning of the end - inescapable recognition of just how serious the Dome's roof problems were.
In March 1993, before reroofing began, Gemperle wrote in a memo to Haner: Dome facilities manager Don Suiter "wants to go on record as having concern about pressure-washing the bare concrete on the roof shells. The concern is that if any hairline cracks exist, water could get through and soak the Tectum, which might then fall down on people."
In the summer of 1993, the roof contractor failed to clean the roof properly with trowels and sandblasters. When work resumed this past March, workers switched to high-pressure water blasters. On April 1, water-stained tiles underneath a water-blasted bay began to bulge.
County officials did a series of tests, including a pull test on one tile, and decided the tiles were OK.
On July 19, the four tiles fell and the Dome was shut down.
A week later, city officials informed the county that it was violating state law by stripping off the roof's insulation without replacing it. The county has asked the city to waive the insulation requirement.
Two days ago, a new interim stadium director, Dick Sandaas, appointed a task force to study the Dome and all its problems.
Where that leads, no one knows.
Kingdome spokeswoman Carol Keaton wonders how long it will take for the stadium to recover. She said everybody seems to forget the $50 million worth of improvements that have been made over the years to the lighting, the turf, the seating and the restrooms.
"The Kingdome has been nationally renowned, and will continue to be, once we get back on our feet and with the roof over our heads," she said.
--------------------------------- A 20-YEAR LIST OF FLUBS AND FIXES ---------------------------------
November 1972: Ground is broken for the Kingdome, six years after voters approved funding.
November 1973: Contractors decide to use Tectum for the Dome ceiling based on the tile's fire-resistance and acoustical properties.
December 1975: Foam insulation is finished on the last two roof sections and Seattle immediately gets 22 straight days of rain before the sections can be sealed. The foam is covered while still damp.
January 1976: Two months before the stadium is to open, various roof leaks are discovered.
March 1976: The Kingdome opens.
July 1981: Just before the roof's five-year warranty expires, the contractor is called upon to repair cracks in the outer membrane.
Fall 1982: Because of leaks, damage from weather and birds, and general unsightliness, King County hires a consultant, David Nordfors, to recommend what should be done. Nordfors and another consultant eventually conclude the roof should be completely recoated with a new waterproof membrane.
Fall 1983: A contractor, Vertecs, begins the reroofing, with a design that calls for using vents and channels in the roof to help moisture escape.
November 1985: Avalanching ice and snow on the Kingdome roof shear off and destroy many of the vents. The damage goes unnoticed for some time. Eventually, large leaks begin appearing. King County rehires Vertecs to remove the vents, fill the channels and return the roof to roughly its 1975 design.
October 1986: In the annual roof inspection, it is found that birds have pecked holes up to 6 inches wide in the roof coating, allowing water to leak into the foam insulation.
Sometime in the late 1980s: County employees cut 32 crude trenches into portions of the insulation and roof membrane, trying to release trapped water. The trenches were left uncovered and more water leaked into the roof system.
March 1989: The county sues contractors and consultants involved in the 1983 reroofing. It settles out of court two years later for $600,000 - not much more than it cost to press the litigation.
1991: Through the year, several reports indicate new tears in the roof membrane, new holes pecked by birds and a variety of leaks creating puddles in the arena below.
May 1992: Kingdome officials and consultants discuss tearing off the old roof and putting on a thin membrane of cement and rubberized paint.
March 1993: As it prepares to award a new roofing contract, a Kingdome official tells other county officials that he worries pressure-washing the roof could force water through small cracks and endanger the Tectum tiles.
April 1994: With baseball season imminent, a Kingdome worker points out discolored ceiling tiles, prompting a week of concern and investigations about whether the tiles are secure. After further inspections and physically pulling on various tiles, stadium officials assure the Seattle Mariners that everything seems OK.
July 19, 1994: Four Tectum tiles crash into the seats just before a Mariners game. That game is canceled, the Dome is closed and on July 23 crews begin stripping the ceiling of its 40,000 tiles.
Copyright (c) 1994 Seattle Times Company, All Rights Reserved.