Copper-clad Stainless Steel Replaces a Tornado-damaged Roof at the St. Louis Airport

Hundreds of people milled about the terminals at Lambert-St. Louis International Airport on the evening of April 22, 2011. Three airplanes with passengers on board sat on the tarmac. It was business as usual at one of the largest municipal airports in the country. But meteorological conditions were anything but usual. A powerful supercell over St. Louis spawned an EF4 tornado (view the Enhanced Fujita Scale, which rates the strength of tornados by the damage caused, on page 2) packing 150-mph winds. The twister barreled directly into the airport 11 miles northwest of downtown, blowing out half the floor-to-ceiling windows in the main terminal and inflicting approximately $30 million in damages. In addition, the tornado seriously damaged part of the copper roof over Terminal 1.

CopperPlus was installed in stages over the domes at Lambert-St. Louis International Airport. Like solid copper, copper-clad stainless steel acquires a patina over time.

CopperPlus was installed in stages over the domes at Lambert-St. Louis International Airport. Like solid copper, copper-clad stainless steel acquires a patina over time.

The 55-year-old roof was iconic and beautiful. Its four copper domes had been the crowning glory of Lambert-St. Louis International Airport, welcoming up to 13 million international passengers each year. But the roof had been showing its age for some time, leaking often and requiring frequent maintenance. Following the tornado strike, airport officials made the difficult decision to permanently retire the roof. “The tornado damaged less than 10 percent of the total roof, but that section needed to be totally replaced,” explains Jerry Beckmann, deputy airport director of Planning & Development. “That damage, plus the fact that the roof was almost 60-years old, influenced our decision.”

Airport officials were challenged to install more than 100,000 square feet of material over four domed vaults as quickly as possible with minimal disruption to the public. Beckmann, who is an engineer, wanted a roof that was watertight and capable of withstanding high winds while airport administrators wanted to maintain the roof’s mid-century architectural integrity. All parties wanted the project completed as economically as possible with results that were aesthetically pleasing, historically appropriate and, most important, built for harsh weather events.

COPPER AND STEEL

They found the solution in copper-clad stainless steel, a material that has been used in roofing applications for roughly 50 years. The selected ASTM B506-09 architectural metal features two outer layers of 100 percent copper strip roll bonded at very high pressures to a core of Type 430 stainless steel, the same metallurgical bonding process used to make U.S. quarters and dimes. The material delivered the natural beauty and patination properties of solid copper with the strength and durability of stainless steel—exactly the attributes desired by officials at Lambert-St. Louis International Airport.

“Copper-clad stainless steel is a great-looking material that can be fabricated for any roofing style. You can’t tell the difference between it and straight-up copper,” says Shane Williams, vice president of Civil Construction for Kozeny-Wagner Inc., the Arnold, Mo.-based general contractor awarded the public bid by the city of St. Louis. “It’s stronger, has a better shelf life and costs less than pure copper. This allowed us to bid competitively for the job and even return a credit to the city of St. Louis.”

Workers install CopperPlus batten-seam panels over a dome at Lambert-St. Louis International Airport. Stepby- step, the installation of CopperPlus is virtually identical to that of copper.

Workers install CopperPlus batten-seam panels over a dome at Lambert-St. Louis International Airport. Step-by-step, the installation of CopperPlus is virtually identical to that of copper.

The owners of Missouri Builders Service Inc., the Jefferson, Mo.-based roofing subcontractor, were attracted to the material’s lighter weight and easy solderability. “We were going to have to maneuver a lot of material on the job site and perform a very large amount of soldering to cover four domes,” notes John Kinkade, Missouri Builders Service’s vice president. “We liked that copper-clad stainless steel had a lower thermal conductivity for easier soldering. That was important to us, given the scope of the project.”

The $6.7 million project to replace the airport roof was announced at a press conference in March 2014 by St. Louis Mayor Francis Slay, St. Louis County Executive Charlie Dooley and Lambert-St. Louis International Airport Director Rhonda Hamm-Niebruegge. “The new skin will shine of raw copper like it did in the mid ’50s when the terminal was built,” Slay stated in a press release issued by the airport. “The roof will slowly transform in color again in time as this airport serves new generations in this region.”

WEATHERING NATURE’S WORST

Copper-clad stainless steel has become more popular in tornado and hurricane-prone regions of the U.S. in recent years, thanks to the strengthening of building codes for wind-lift and hail-resistance standards. Copper-clad stainless steel conforms to Miami-Dade BCCO requirements and exceeds UL2218 Class 4 hail-test requirements; wind-uplift tests have shown its strength to be equivalent to steel at the same gauge. It offers a strength advantage compared to solid copper, providing higher tensile strength and yield strength at a thinner gauge than monolithic copper.

Numerous churches, college buildings, museums, private residences and other buildings nationwide now feature copper-clad stainless steel in their custom roofs, dormers, cupolas, flashings and downspouts. Notable installations include the following:

  • Several 67-foot panels of copper-clad stainless steel were rolled onsite, then lifted and put in place by a crane to replace the ice-damaged roof at the St. Francis of Assisi Catholic Church, Traverse City, Mich.
  • In 2012, more than 30,000 square feet of copper-clad stainless steel were installed in the fascia and coping of the Trinka Davis Veterans Village, Carrollton, Ga., the nation’s first privately funded U.S. Department of Veterans Affairs’ VA facility.
  • In 2014, the material was selected for a 2,100-square-foot perforated sunscreen installation in San Francisco’s Mission Bay neighborhood, one of the most significant urban development projects in the U.S.

PHOTOS: MISSOURI BUILDERS SERVICE INC. AND LAMBERT-ST. LOUIS INTERNATIONAL AIRPORT

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A Roof is a Building Owner and Homeowner’s First Line of Defense in a Storm

The Midwest has been battered by unrelenting storms this year. Last week, I spoke to a friend who had just returned from visiting mutual college friends in Minnesota. They experienced a strong storm during the visit, and while they were all sleeping, our friends’ house was struck by lightning. The acrid smell of smoke awoke them and the eight people (four of which were children) scurried outside in their pajamas, leaving all their belongings inside. The local fire department contained the fire to the garage, which is attached to the house. However, the smoke damage inside is so severe that the family of four is currently residing in a hotel while their house is professionally cleaned.

Stories like these are all too common recently and this one hit a little too close to home for me. It seems easier (and less scary) to think storm damage won’t happen to me when those who are affected are strangers on the news. However, according the Alexandria, Va.-based Independent Insurance Agents & Brokers of America Inc., extreme-weather events and natural disasters are becoming more prevalent. The organization reports that since 1987 there have been eight natural disasters with insured losses greater than $1 billion; before 1987, there was one.

Although the Greensburg, Kan., EF5 tornado that occurred in 2007 didn’t cost that much, it destroyed 95 percent of the town, which is scary enough. Greensburg is coming back as a model for the rest of the country—rebuilding stronger and more sustainably. Read about one of the town’s strong, sustainable projects—the BTI-Greensburg John Deere Dealership, which is a metal building featuring roof-integrated daylighting systems designed to withstand high-velocity impacts—in “Tech Point”.

About 550 miles to the east, an EF4 tornado inflicted $30 million in damage on the Lambert-St. Louis International Airport in 2011. To rebuild four copper domes that were the crowning glory of Terminal 1, airport officials opted to use copper-clad stainless steel, specifically because they wanted something beautiful that could withstand harsh weather. Read about the roof system in “Tech Point”.

The other night, a clap of thunder actually shook my house for what seemed like a full minute. I’ve always been the type of person that enjoys storms but, after my friends’ incident, I have to admit I feel less safe in my home. I immediately looked online to determine whether I should move to the basement and then I stayed awake until the storm passed to ensure my roof didn’t catch on fire. I think it’s time I look into a better, stronger roof.