New copper roof renews iconic St. Louis airport
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Almost 60 years after they were first installed, the historic copper domed roof vaults at Lambert-St. Louis International Airport’s Terminal 1 had been through a lot. Its original installation didn’t allow for thermal movement and its metal roof had torn itself apart by fatigue in numerous locations. After weathering much wear and tear, including a brush with an F4 tornado, the aging, leaking roof was in definite need of replacement. A $6.7 million project replaced this iconic architectural landmark and won the metal roofing retrofit category.
With a tight budget and a milestone completion date that could not move, general contractor Kozeny-Wagner, Arnold, Mo., was challenged to provide a competitive and responsible solution. It also had to adhere to the historical significance of renowned architect Minoru Yamasaki’s ultra-modern iconic design from the 1950s. The results are energy efficient and mirror the original design. The scope of the project included a new high-tech, cool roofing design with enhanced life expectancy. The existing copper roof was removed along with existing wood and insulation down to the domed concrete deck. New insulation was installed with strips and plywood over the top to create a vent under the entire roof. Center parapet walls now allow the air to flow to and from the outside parapets.
Four Roof Domes
To restore the four roof domes to their original historic look, the architect, Jacobs, Pasadena, Calif., specified 102,000 square feet of 24-gauge CopperPlus panels from Heyco Metals, Reading, Pa. The CopperPlus panels feature two outer layers of 100 percent copper metallurgically bonded to a core of Type 430 Stainless Steel. “Panel widths were custom manufactured for the unique curvature of the dome geometries,” says Shane Williams, vice president of civil construction services, Kozeny-Wagner Inc., Arnold, Mo., the general contractor. “Each panel was precisely measured, cut and installed on-site by skilled sheet metal workers
[from Missouri Builders Service Inc., Jefferson City, Mo].”
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CopperPlus minimizes thermal movement and reduces hail damage risk due to the support of the stainless steel base material. Bonding the copper with stainless steel core adds durability. The roof is laid with a layer of high temperature ice and water shield. There are fully soldered valleys that tie into the flat lock panels at the center of the domes.
“As an engineer, I wanted to make sure the replacement material would be watertight and hold up well in storm events,” says Jerry Beckmann, the deputy airport director of planning and development. “The airport directors were concerned about maintaining the historic architectural integrity of the roof. I did some investigating and liked what I heard about the copper-clad material. It looks identical to solid copper, but doesn’t expand and contract as much in the heat, and has better soldering characteristics.”
“CopperPlus provides a significant strength advantage for the St. Louis Airport,” says Richard Petty, Heyco architectural product manager. “There have been wind uplift tests in Miami-Dade County showing the strength of CopperPlus is equal to steel at the same gauge. It’s the perfect material for wind events like those seen in St. Louis.”
Williams says Kozeny-Wagner inspected and documented construction activities during every phase of the project, assuring quality from start to finish, preserving the project’s historical significance. Extensive pre-construction planning resulted in a schedule and sequencing plan that finished the project on time.
A New Skin
Now installed, the original light bronze color of the copper is slowly beginning to turn dark brown due to exposure to the elements. Over the next 20 years or so, the roof will patina to a soft green.
“The days are numbered to see the wonderful green patina on top of this architecturally historic building,” says St. Louis Mayor Francis Slay. “The new skin will shine of raw copper like it did in the mid-1950s when the terminal was built. The roof will slowly transform in color again with time as this airport serves new generations in this region.”
The judges unanimously awarded the terminal restoration winner in its category. They cited its use of metal to capture its unique look, and the craftsmanship and attention to detail required for the soldering of its many seams.
Sidebar: Terminal 1 Cooper Roof Replacement, St. Louis
Completed: December 2014
Total square footage: 77,000 square feet
Building owner: City of St. Louis, Lambert-St. Louis International Airport
Architect: Jacobs, Pasadena, Calif.
General contractor: Kozeny-Wagner Inc., Arnold, Mo.
Metal installer: Missouri Builders Service Inc., Jefferson City, Mo.
Copper panels: Heyco Metals Inc., Reading, Pa., www.heycometals.com
