Teams may go, but Dome roof is here to stay
A recent inspection found little wrong with the 28-year-old bubble, though it has lasted well past its 20-year life expectancy.
By KEVIN DUCHSCHERE, Star Tribune
Last update:
July 16, 2010 - 1:42 AM
The Metrodome is a dinosaur among professional sports stadiums, but its once tear-able roof sure is holding up.
A recent inspection of the 10-acre roof found some holes in the inner liner and some areas on the outer Teflon-coated fabric that need repair.
But, overall, the 28-year-old bubble looks to be in fine shape and should be OK for at least another four years.
"In this climate, with less UV [ultraviolet rays] and less humidity [than other areas], the materials continue to perform well," Metrodome engineer Steve Maki told the Metropolitan Sports Facilities Commission on Thursday.
Replacing the roof would cost $12 million to $15 million and take about five years to make it happen. By then the Dome's lone remaining tenant -- the Minnesota Vikings -- hopes to be moving into a new facility.
The roof consists of two layers -- the outside Teflon surface, 1/32nd of an inch thick, and the inner liner of woven fiberglass that is 1/64th of an inch thick.
Three fabric samples taken from the outside layer revealed a film of oily grime on the underside, likely a remnant of years of monster truck rallies.
The inspection, performed by roof contractor Birdair Structures, showed fabric strength comparable to original specs although it's past its 20-year life expectancy.
Inflatable stadiums have fallen into disfavor in recent years, and some have been pulled down in favor of open or retractable-roof arenas. Big fans needed to keep the roof inflated cost a lot to operate. In northern climes, snow must be melted to avoid roof collapse.
The Metrodome roof deflated three times shortly after it was built, because of snow. In 1990, the commission sued its builders for alleged defects and won $3.6 million, about a fourth of what it had sought.
Recently workers pulled the plug on fans keeping aloft the fabric bubble in Vancouver's B.C. Place; it will be replaced with a retractable roof. Remaining fabric-domed stadiums include the Silverdome in Pontiac, Mich., and Syracuse University's Carrier Dome in Syracuse, N.Y.
That leaves the Dome, commission executive director Bill Lester said, "on the edge of the oldest fabric roof in existence."