After the storm

03 Oct 2011

The Big Easy of retro-fit cladding wins the day

Images of the Louisiana Superdome, New Orleans sheltering thousands of homeless residents in the aftermath of Hurricane Katrina are burned in the minds of most of us who watched in horror from the safety of our arm chairs. But as the media’s attention swiftly moved onto new topics, the city was left with the formidable task of restoring the battered icon.

Taking stock
The first step was to assess the damage. Trahan Architects, Baton Rouge, La., conducted the initial study. “The original system was riveted into the decking and the only way to repair a panel was to take out the ones around it. We took an inventory of every damaged panel on the building to prepare a repair package for FEMA. We could have replaced just the damaged panels, but we would have had a striped façade that looked like a zebra,” explains Brad McWhirter, project manager.

The Brief
The brief demanded a system that would allow repair of single panels without requiring removal of the whole system. In essence this was a call for a custom system that had to meet specifications for resistance to wind and other severe weather conditions. The incumbent structure utilised an unwieldy, horizontal overlapping panel system.

The Challenge
The project team’s biggest challenge was the timeframe - 180 days to design and develop the system. According to Doug Bruza, senior project manager for Gibbs Construction: “The biggest thing was to provide an individually replaceable metal wall panel and attachment system. The original wall system was installed from bottom to top. So if a panel was damaged you would have to take off 118ft of panels to replace just one,” he says. The scale of the project was such that any savings on installation time per unit would be multiplied up and equate to a substantial reduction in man hours and subsequent cost saving overall.

The Solution
Time was of the essence, but thanks to a specially developed Kalzip system, the installation team were able to draw on the benefits of a new façade system previously unavailable. “Because of its ease of installation, the façade system can drastically reduce time and labour. It uses a mullion clip and a notch system, which is an adjustable clip system that provides a slot connection point for the mullion. It is also a rainscreen system,” Bruza said.

This state of the art system sees the waterproof joint moved from the exterior of the skin to behind it in the form of a hermitically sealed barrier. The team went through three or four different designs before deciding on the final system. “This system is lightweight and performs very well in testing for wind, rain and severe weather conditions. The testing also determines the spacing of the panels. A big part of installing the panels on this new façade system is lining up the mullions. If that’s not done right the panels will not fit well, nor click or press into place as they should,” explains Chad Schexnayder, sales manager for Ryerson Metals, the panel supplier.

Because of the complexities of the new system and the fact that it was essentially untried, a third-party testing lab was engaged. The first task was to build a wind tunnel analysis model as the Superdome had acquired some neighbours since the original plans were drawn up in 1967. These adjacent buildings significantly affected the wind loads on the structure which had to be taken into account.

In the end, the Kalzip system proved to be excellent, saving both time and money on installation, Brad, “this has probably added a lifespan of over 30 years to the building….”

Quick Facts
Renovation architects: Trahan Architects + Billes Architects & Sizler Thompson Brown
Contractor: Gibbs Construction
Product: Kalzip FC Façade
Panel supplier: Ryerson Metals
Lower section: 85,000 sq ft
Upper (curved) walls: 280,000 sq ft

Click here to listen to a podcast with Trahan Architects’ Brad McWhirter.

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