Duluth City Hall Undergoes Major Wall Restoration Project

For the first time in nearly a century, the travertine walls of the Duluth City Hall building in Minnesota will be properly cleaned and restored to their former glory.

The Duluth News Tribune reports that the City of Duluth architect Tari Rayala is leading a major restoration project in cleaning the building’s walls. Since the city hall opened in 1928, the walls, once vibrant and pristine white, have slowly decayed after decades of indoor smoking, indoor heating, and skin oils from people touching the walls. The walls now look worn, dingy, and jaundiced.

The travertine cleaning work began last month after the Duluth City Council approved of $107,000 in funding in April. The cleaning is expected to wrap up by the end of the month.

The contractor responsible for the project, Premium Plant Services, works at night using an innovative technique invented by Sponge Jet, a company based in New Hampshire. Representative from both companies were in Duluth last week observing the work.

“I’m very pleased,” said Ted Valoria, Sponge Jet’s Vice President for North America.

The process involves delivering aluminum oxide particles wrapped in small dry sponges to the travertine walls via an air hose that projects air at 40 pounds per square inch.

“In historical preservation, it’s called ‘micro-abrasion,'” Valoria said, who pointed out that since the technique was invented 27 years ago it has been used in more than 100 countries, in buildings as illustrious as the White House and the Guggenheim Museum in New York.

“The workmanship is truly professional,” she continued, complimenting the project crew. “They’ve got an appreciation for the finesse that’s required.”

The city hall is part of a prominent city district that houses the Federal Building and the St. Louis County Courthouse. Rayala hopes that the restoration work on City Hall will motivate the other buildings to follow suit.

“Once they see what we’ve done,” Rayala said, “they’ll be copying us.”

With a demand in the United States at about 0.85 million tons every year, travertine is one of the most popular natural stone building materials in the country.

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