Snug retrofit

Hurricane Katrina struck the Gulf Coast with a vengeance, leaving a trail of destruction in her wake. Waterfront businesses took the onslaught head on. The Seventh Street Wharf of the Port of New Orleans was among her victims and its roof needed immediate attention.

Roofing contractor J. Reynolds & Company tapped Architectural Building Components for the job. To avoid the great cost of replacing the roof entirely, the team elected to retrofit the roof’s existing R-panels with a 22-gauge, 18-inch wide, 238T system. While 24-gauge panels would have met International Building Code requirements for wind uplift pressure, the Port of New Orleans chose not to take any chances, opting instead for the thicker, sturdier material.

Port authorities chose a Roof Hugger application for the project, in which a notched 16-gauge “Z”-shaped metal piece fits over the ribs of the existing standing seam metal roof and acts as the purlin, or structural framing, underneath the new roof panels. The Roof Hugger system attaches through the existing roof to the original structure, maintains the integrity of the original design loadings and allows for optional insulation, both of which were important for the client.

Port authorities decided to metal-retrofit the roof for several reasons. This solution offers numerous benefits including improved energy efficiency and R-values and minimal need for maintenance over its 30- to 50-year lifespan. This resolution also enabled business to function as usual without the costly interruptions and environmental exposure of a total roof replacement.

“The engineers at the Port of New Orleans quickly recognized the 238T panels were the best roof system they could find for this project,” says Charlie Smith, president of Architectural Building Components. “We were able to provide multi-span clips on the edge zones to eliminate the need for additional framing with a system that allows for individual panel replacement anywhere on the roof and unlimited thermal movement.”

The installation team was led by J. Reynolds & Company vice president and program manager John Camp. Under his direction, the 110-foot long panels were manufactured onto the roof using Architectural Building Components’ “Archzilla” truck. The installers then easily carried the flexible sheets up and over the ridge of the roof.

“We decided to use this metal retrofit system due to its long-term performance and superior weatherability in a notoriously hurricane-prone region,” says Camp. “The convenience of using Architectural Building Components’ Archzilla roll forming truck onsite and its ability to produce long, uninterrupted panels onto the roof were other key factors in our decision to select the 238T system.”

The symmetrical 238T panels have fixed clips that can be installed in any direction, along with a separate seam cover that makes repair or replacement of panels a simple task. Additionally, by using the system’s multi-span clip over regular, fixed clips, the client achieved double the wind-load capacity, from 45 to 130 pounds per square foot over purlins at 60 inches on center. Because the system uses a separate cap, the sealant has no contact with the clip, making the 238T panels much more water-tight at installation than traditional two-inch panels.

The installation team is putting the final touches on this metal roofing retrofit just as forecasters predict another especially busy hurricane season. With the new 238T metal roof securely in place, the Port of New Orleans can expect to weather the harshest hits from Mother Nature ­— at least inside the Seventh Street Wharf.

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