Palladio Awards

Project: The Cathedral of St. John the Baptist, Charleston, SC

Architect: Glenn Keyes Architects, Charleston, SC; Glenn F. Keyes, AIA, principal in charge; Rueben J. Solar, AIA, project architect.

Contractor: Hightower Construction Co., Jimmy Hightower, President

 

 

JUNE 2011 » 2011 Palladio Winners

Sympathetic Addition

Winner: Glenn Keyes Architects

A Storied Steeple

By Nancy A. Ruhling

When the Cathedral of St. John the Baptist, an architectural icon in historic Charleston, SC, celebrated its centennial, the Diocese of Charleston decided to top off the celebration by erecting a steeple. For a century, the Gothic Revival brownstone cathedral, which was completed in 1907, had stood sans steeple on Broad Street, which is also home to City Hall, the County Courthouse and St. Michael's Church. It was always intended to have a heavenly spire that inspired, but time and money took their toll, and somehow the project never got off the ground.

So when the congregation decided to do a much-needed renovation in 2007, it commissioned Glenn Keyes Architects in Charleston not only to refurbish the brownstone exterior and dismantle and re-lead the 14 antique stained-glass windows by the German-based company Mayer Studio, but also to design a belfry and steeple. "The importance and location of the building mandated that we create something architecturally appropriate and significant," says architect Glenn F. Keyes, AIA, adding that although he has worked on many historic restorations, he had never designed a steeple. Keyes and his team were familiar with the cathedral because they had restored its sanctuary in 1995, and the project architect, Rueben J. Solar, AIA, has been a parishioner for nearly two decades.

The original building, designed by architect Patrick Keely, burned in the Great Fire of 1861. When Keely, who designed a great number of churches in New England, was called upon to design its replacement, he followed the existing footprint and presumably included a spire. But no drawings have ever been found. "All we had was a bird's-eye-view sketch of the original building's 1851 steeple, but we couldn't determine any real detail from it," says Keyes.

Instead, Keyes turned to the existing building for inspiration. "We decided to incorporate design motifs from the church into the spire so it would be compatible with the original," he says. "But there were huge structural constraints that at first glance appeared to tie our hands."

In addition to adhering to rules for historic structures, the Charleston team faced three obstacles that, using conventional construction techniques, probably would have shrunk or sunk the soaring steeple:

  • The soil has deep layers of very soft clay.
  • The city is in a hurricane zone.
  • Anti-earthquake standards are on a par with California's strict codes.

Thus, the steeple had to be sturdy and substantial enough to carry on the architecture of the cathedral, but it also had to be virtually as light as a goose feather.

"This project was a pure structural engineering problem," says project structural engineer John Moore, PE, of Charleston-based 4SE. "The existing tower had settled a little, but it was minor because the site had been pre-consolidated by the weight of the previous church and had almost reached equilibrium. The tower also was in good condition because they used Portland cement, which is stronger than what was used on older structures, and it had not deteriorated. We determined that adding a low, lightweight steeple wouldn't hurt."

But to be aesthetically pleasing, the 86-ft.-high cathedral needed a steeple that looked as though it touched heaven. "We couldn't do something conventional like modify the soil," Keyes says. "It would have cost $600,000 just to do that, and we only had $2 million of the total $6.2-million renovation budget for the belfry and steeple."

Jimmy Hightower, president of Charleston-based Hightower Construction Co., came up with a sea-change solution: Using boat-building technology to erect an 82-ft. open-style steeple and lightweight belfry that would nearly double the cathedral's height.

"It was a Eureka moment," says Jesse Rhodes, Hightower's special projects manager. "Nobody working on the team had ever done this before. When I checked with steeple makers, they primarily offered closed-in designs hiding a matrix of internal framing. I did a lot of research and found out that up in New England, a lot of historic steeples were built by boat builders. Boats have to stand up to high dynamic loads similar to a steeple in high winds. I had a lot of experience building boats because Hightower also has a boat-crafting company, so it all came together."

It was a great idea that was easier said than set into stone. "If we didn't do this right, the steeple could overturn like a mast," Keyes says. "It was like a big sail, so we used that idea to our advantage. We had to design a steeple that was lightweight and would allow air to flow through to minimize the wind load on our 'sail.'"

Rhodes, who had never worked on a steeple before, used lightweight cold-mold construction for the belfry, spire and towers. "A stainless steel frame that goes from the spire to the belfry and drops down to the existing building is the backbone of the addition," he says. "It ties everything together."

Beneath the spire, which is an open-mesh lantern that flows with the wind, the steel frame was encased by engineered wood boxes that were constructed of marine-grade plywood and epoxy and encapsulated in Fiberglass. The 12-ft.-high belfry was made of 8-in.-thick pre-cast structural concrete that matches the color and pattern of the century-old "weathered" brownstone building. The upper towers were veneered in 2-in. cast stone that picks up the architectural detail and hue of the 1907 cathedral.

"I drew in details of the stone in a 3-D computer model and cut foam forms to cast," Rhodes says. "The details are incorporated into the wall, so down the road, there's no worry about their coming loose or falling off. Overall, our No. 1 goal was to make the addition as maintenance-free as possible for a 100-year lifespan. With the help of one of our gifted superintendents, Paul Willis, we constructed the pre-cast elements in-house."

Hightower and Rhodes' lightweight solution played heavily into the success of the project. "The light and airy design allowed us to take the steeple higher than if it were solid," says Moore. "I worked with a geotechnical engineer to help make a computer model of the tower and soil, and we went back and forth with the architects until we figured out how high we could go."

To make the belfry and spire "match" the cathedral, Keyes built upon the motifs of the historic building. The Gothic Revival arch that tops the lantern level is a copy of the one above the door by which worshippers enter, and the louvered frames of its trio of arches at the belfry are copper copies of the wooden windows in the rest of the church. The stone chalice that acts as a finial to the front door's arch is repeated in the spire's archway but in lighter-weight copper.

"The belfry and steeple are high, and we didn't want to have to worry about routine maintenance," says Keyes. "The copper cladding won't rot like wood and doesn't have to be painted, and the pre-cast stone doesn't need routine care."

For the crowning touch, the cross, Keyes again turned to the original architecture, replicating the Celtic cross on the rear parapet. "But this one is bigger – it's 14 ft. tall, not seven," he says. "The one in back is copper that has aged green, but the congregation decided that the front copper cross should be gilded to make it more prominent."

Once the 14 cold molds for the middle arch and spire were made, they were shipped in pieces to Erno Ovari, president of Copper Exclusive in Midvale, UT, who applied the copper cladding to them and the cross, creating a design that has no visible seams by combining different thicknesses of the metal.

Ovari, a European native who has spent his career restoring castles and cathedrals, says elongation issues were a challenge. "In Charleston, the summer heat is relentless but can be shocked into freezing temperatures within moments when a storm hits. This extremely abrupt change in temperature causes metal to go from an expanded state to a contracted one. Copper expands and contracts to a much higher degree than the subsurface it covers. This condition eliminated the option for direct fastening of the metal on the steeple. In this case, we had to resort to 'old technology' that has kept buildings in Europe standing strong and maintenance-free for centuries."

There was no room for error, Ovari says, because the middle arch and steeple had to be assembled on the ground in Charleston then lifted to the cathedral's roof. "Doing it this way was innovative, and we needed to engineer perfect transitions between the parts because of this," he says. "And we had to be sure they were watertight."

Flatbed trucks transported the 30 elements, which ranged from the 28,000-lb. middle archway to the 15-lb. tower finials, to the cathedral, where they were fitted together like a custom jigsaw puzzle. "It was challenging to get the pieces to the church," says Rhodes. "The Charleston streets are narrow, so we had to figure out how to turn the trucks, and we were limited by how much weight we could lift because only a certain size of crane would fit into the churchyard. We had to do a weight study to figure it out. Constructing the upper towers to withstand the mobilization was the hardest part."

To put the spire in an eternal spotlight, Holland Lighting Design, which is based in Charleston, used a fiber-optic system that makes the gold cross glitter in the night sky. "We wanted to emphasize the steeple rather than wash the entire building in light," Keyes says. "The fact that it's a fiber-optic light source makes it easier to maintain. The lights are inside and shine up through the spire underneath the lantern. And they are relatively easy to reach and replace."

Once the steeple and belfry were designed, everything else fell into place. During the renovation, Hightower chose Dan Lepore & Sons Co. of Philadelphia and stone consultant Ivan Myjer, principal of Building and Monument Conservation based in Arlington, MA, to replace more than 2,000 of the cathedral's brownstones and re-point the building with 23 miles of mortar. The project, started in 2007, and was finished in 2010.

In addition to the Palladio award, the project has received awards from The Associated General Contractors of America, AIA South Carolina, AIA Charleston, the Historic Charleston Foundation and the Preservation Society of Charleston. "Since completion, the response has been overwhelmingly generous toward not only the design with regards to the cathedral itself but also to her place in the skyline of the city," says Solar. "Most parishioners have said that the design seems to be what the original church was supposed to have as its steeple. Others respond about the pride they have as they drive into the city and see their church steeple finally being represented in the Holy City with the other steeples."

Today, when the Cathedral of St. John the Baptist's three new French bells call worshippers to mass, they also call attention to the new addition. "Charleston is so flat, and most of the buildings are only three to four stories," says Rhodes, "With the steeple, people can now see the cathedral above the rooftops." Keyes agrees, adding that "this was a once-in-lifetime project. Broad Street is a major east-west street, and the cathedral's new spire has changed the skyline of Historic Charleston forever." TB

 

«BACK TO JUNE 2011 TABLE OF CONTENTS

 

Have something to say about this article? Feel free to comment!

Comments feed Comment Feed RSS 2.0

1. Terry Kearns (06/24/2011 18:05:30)  
Cathedral of St. John the Baptist new steeple

Congratulations to all for this wonderful project. And thanks to Traditional Building for the excellent documentation of the challenges and solutions. Bravo.








 

www.traditional-building.com
Home | Free Product Literature | Advertising Information | Subscribe | Privacy Policy | Site Map | Contact Us

Traditional Building Period Homes Traditional Building Portfolio traditional product galleries traditional product reports
rexbilt BuildingPort.com Tradweb Traditional Building Conference Palladio Awards
Twitter Facebook

Copyright 2014. Active Interest Media. All Rights Reserved.