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A Bold Change

A metal roof is the crowning glory of a decade-long renovation and earns an MCN Building and Roofing award for 2017

Christ Church Dec17 2
Photos: Martin Knowles Photo/Media

Surrounded by towering giants, Christ Church Cathedral in Vancouver, British Columbia, Canada, had undergone a 22-year, four-phase renovation program that included a complete restoration of the interior, seismic upgrade and new bell tower. Its final flourish was the installation of a new metal roof to replace the faded, failing asbestos shingles, which themselves had replaced wood shingles. The judges of the 2017 Metal Construction News Building and Roofing Awards called the decision to install a zinc-coated standing seam roof on the 123-year-old church a bold one, and admired how the new roof complemented the old bones of the church, lightening the heavy, stone walls. For that, they awarded the project the best in metal roof retrofits.

One Solution for Three Problems

“We’d been working on the church for a very long time,” says Hugh Cochlin, MRAIC, LEED AP, principal at Vancouver-based Proscenium Architecture & Interiors. “In the third phase, the roof installation, we tied three elements together.” The first of those elements was the installation of large, steel trusses that finalized the seismic improvements.

The second was sound insulation. “The building is right on George’s Street,” says Cochlin, explaining the second problem, “and it gets lots of traffic noise. Acoustically, we used the roof to isolate the noise by installing acoustic batt insulation.”

The third problem was improving the weather protection. The wood and asbestos roofs had failed, and the congregants wanted a solution that would last. “Everybody thought the original roof was slate,” says Cochlin. “We looked at slate, but the building couldn’t carry a slate roof. Cedar made no sense. Asphalt shingles made no sense. That led us to a metal roof, which made complete sense. We led the client to a zinc roof.”

Before the new zinc-coated metal roof

Finding Zinc

Proscenium associate architect, Ben Nielsen, researched precedents and found a photo of a cathedral in Montreal that had a standing seam copper roof, and another in England with a standing seam metal roof. “We were looking for consistency and integrity of the original form,” Nielsen says. Because of the importance and age of the cathedral, it was a heritage project and needed to follow the “Heritage Practice Guidelines.”

The team selected the traditional prePATINA blue-grey color from Woburn, Mass.-based RHEINZINK America Inc. “We looked at different roofing materials and focused on durability,” says Proscenium associate, Ron Clay, MRAIC, who managed the project along with Nielsen. “We wanted it to be a hundred-year solution. We weren’t looking at ongoing maintenance or want it to fall apart in a windstorm. There was enough copper in the area. Zinc came up pretty quickly.” One of the considerations was how the roof would weather, and the judges agreed with the design team that its aging patina would suit the cathedral even more completely.

The completed project showing the new roof and the bell tower

An Installation Challenge

Installing the roof was, in itself, a monumental task. General contractor, Scott Construction Group, Burnaby, British Columbia, built a scaffolded second roof to weather-in the building during the re-roofing. There were structural problems that needed to be addressed as well. “When stripped all back,” Cochlin says, “the original roof had a slope like a saddle.”

Pacific Building Envelope Maintenance Ltd., Delta, British Columbia, did all the framing and leveling. Above the original rafters, carpenters built up the roof, using tapered rafters to run on top of each of the existing rafters.

Because of the seismic upgrades, acoustic improvements and the build-up, the roof was much thicker than the previous roof, which created all kinds of problems on the reveals on the fascia, gables and eyebrows. During the structural build-up phase, the team also discovered lead dust that dropped down into the newly refinished interior and needed to be abated.

When it finally came time for the installation of the metal roof, Terry Kellogg, president of TEK Roofing Ltd., Vancouver, put his team on it and then joined them during part of the build. “It was so much fun,” he says. “We had to do a lot of intricate detailing. I came up as a tradesman, and you kind of miss that side of life. It was very nice to get the tools on again.”

A second roof held up by scaffolding protects the already refurbished interior during the roof replacement

Because of the age of the building, TEK Roofing resorted to old-school methods, including using water levels. “It was one constant struggle to get everything true,” he says.

It took about five months to level the roof. TEK Roofing began work in March 2016, overlapping with the framers a bit, and completed the project in November that year. In all, the roofers formed 900 panels and worked on areas of intricate detail around eyebrows. “None of the transitions were straight and square,” Kellogg says. “It was very time consuming; very traditional. We had to solder joints here and there, and there was not a lot of caulking. It was about as close to traditional construction as you can get with materials that are state of the art.”