1994: Kingdome Emergency Roof Repair
Feb 09, 2017 | by Lisa Schaefer
Named after its location in King County, the Kingdome opened in 1976 and was best known as the home stadium for the Seattle Seahawks and Mariners respective football and baseball franchises.
The roof of the Kingdome had been problematic from the beginning. Due to several leaks in the foam roof early on, King County decided to replace the roof with a special coating in 1993.
A consultant was hired to evaluate the stadium and assess the situation. It was determined that the ceiling panels, made of tectum, needed to be removed, and revealed damaged, softened concrete that was in dire need of repair and replacement.
A local coatings application company began to strip the outer roof coating using an abrasive pressure washing method, which resulted in water seepage through the roof.
John Fisher, had been working at Long Painting Company as a project manager at the time and was brought on to assist with the repairs.
“The problem with pressure washing the roof was that it soaked the insulation which then dripped into the inside of the dome,” Fisher said. “Inside the lid of the Kingdome roof were tectum panels, which look like shredded wheat biscuits. They’re supposed to absorb sound, but they also absorb a lot of water.”
Mike Cassidy, president of Long Services Corporation, (a division of Long Painting Company), and his team were brought on to help with the emergency repairs.
“The Kingdome roof could handle a pressure of 7500 pounds per square inch (psi),” Cassidy said. “The City of Seattle wanted to remove the foam roof with a 20,000 psi pressure washer. At that level, you’re using more pressure than the concrete can handle.”
Over time, the tectum panels absorbed enough water that they became extremely heavy. So heavy, in fact, that one day before a Mariner’s game on July 19, 1994, four 26-pound waterlogged acoustic ceiling tiles crashed into the seating area below.
Cassidy said it was this flawed calculation and immense amount of water pressure that caused the roof tiles to soften and start falling from the ceiling.
“All hell broke loose because no one knew how extensive the damage was,” Fisher said. “They had to shut the Kingdome down immediately.”
After about two weeks of another contractor struggling with a pressure washing method on the lid, Long Painting was brought on to provide a sample using an alternative method in hopes of speeding up the laborious process of cleaning adhesive off the ceiling.
“It had taken them about two and a half days to do a 10 by 10 foot patch,” Fisher said. “They estimated it would take years to complete.”
This daunting prediction prompted the engineer in charge of the project to call Long Painting and consult about alternative options to speed up the process without creating more damage.
After observing the ceiling, John Fisher suggested sandblasting, a more aggressive method than pressure washing, would be ten times as efficient.
To hit his point home, Fisher had his team sandblast a small section of roof.
“We got through about 100 square feet in about 15 minutes,” Fisher said. “They calculated that with our method, they could get through the entire roof in about three weeks.”
The Kingdome was losing about $1 million each week it remained closed. So with time constraints taking precedent over budgetary concerns, Long Painting was hired as the new contractor to repair the ceiling as quickly as possible.
Mike Cassidy and his team at Long Services Corporation were brought on to remove all coating and insulation down to bare concrete on the roof and then sandblast that concrete so a new roof could be put on. All this had to happen while work was being completed on the underside of the roof.
“Long Painting had guys working on the ceiling inside while Long Services was working on the roof outside,” said Fisher. “At one point there were about 500 people on that project with the common goal of trying to get the thing fixed.”
Long Painting alone had over 300 people working on the Kingdome emergency roof repairs.
“We mobilized like an army would arrive,” Fisher said. “We brought in all the trucks, man lifts, and equipment necessary. We worked 24 hours, seven days a week, for 71 days straight.”
Access issues proved to be a concern as there were no cranes tall enough in the area to reach to the top of the 250 foot tall ceiling.
Cranes from a German heavy equipment manufacturer, Demag, were brought in, allowing Long employees to reach the ceiling. At one point, all the Demag cranes in America were being used at the Kingdome job site.
Once the sandblasting was completed, liquid concrete, or Gunite, was sprayed onto the concrete lid in order to further stabilize the structure. Upon applying the Gunite, it was found that while the roof was secure, the acoustic value had severely diminished.
“The place sounded like an echo chamber,” Fisher said.
Fisher suggested spray applying cellulose insulation onto the ceiling which brought the acoustic value back to its original quality.
The emergency roof repairs remain, to this day, the largest and fastest job Long Painting has been a part of.
“This was, by far, one of the biggest projects I’ve ever worked on as a project manager during my entire career at Long Painting,” Fisher said. “There were times I slept in the job trailer since we had crews going around the clock.”
It was a common theme at Long Painting to meet a client’s needs by any means necessary, and the Kingdome roof repair was no exception to that rule.
“When you talk about company culture that was the culture at Long – there isn’t anything we can’t do and part of why I joined the company is because of that can-do attitude,” said Fisher. “I don’t care what it is; we’ll engineer it, we’ll design it, and we’ll get it done.”
Repairing the roof cost King County $51 million. A reopening ceremony was held on November 4, 1994, with the Seattle Seahawks returning to the stadium for a regular season game against the Cincinnati Bengals.
The Kingdome was ultimately demolished by implosion on March 26, 2000.