It was cracked, creaked and leaked.
Ever since famed Spanish architect Rafael Guastavino designed the massive dome in the early 20th century at the Cathedral of Saint John the Divine in northern Manhattan, it has been a source of wonder. It has also been a source of grief, requiring seemingly endless repairs.
But now, after a three-year, $17 million rehabilitation, the woes of the 113-year-old leadership have been tended to. Its striking terracotta tiles were repaired and a new copper exterior was added.
“The new roof could easily last 50 to 100 years and there’s no reason why it couldn’t last for centuries with good maintenance,” said Kevin Seymour, associate principal at Ennead, the architectural firm that was in charge of work on the cathedral. , seat of the Episcopal Diocese of New York.
Built in 1909, the dome was one of the first things built on the famously unfinished cathedral, which still lacks a south transept (an arm extending south to complete the cross-shaped plan of the church), not to mention the rest of the two towers on the west façade, facing Amsterdam Avenue and 112th Street. The cathedral, a mix of Byzantine, Romanesque and Gothic styles that is the length of two football fields, making it the The largest in the world, it is nonetheless an official City monument, as well as a beloved New York institution and a popular tourist destination.
The approximately 40 meter diameter dome was never intended to be permanent; rather, it was a temporary cover over the crossing’s four gigantic granite arches until a spire could be erected, at which time it had to be removed. However, the best dome maker of the day was called upon for the encomienda: the firm of architect Rafael Guastavino and his son, Rafael Guastavino Jr., renowned for its beautiful, lightweight, durable, self-loading vaults and arches made of fine interlocking tiles and fast drying mortar.
The Guastavino Fireproof Construction Company constructed the dome by lapping terracotta tiles—more layers near the base and less toward the (thinner) center of the dome—and attaching the base with a steel tension ring. The company completed the work in 15 weeks, including vaults below the crossing floor. However, because the dome was only temporary, it was never given a proper outer covering; instead, asphalt was smeared on top.
The interior of the dome, which rises 50 meters, was also unadorned—what one sees, looking up from inside the church, is simply the reddish, rough underside of the tile.
By 1916, the dome was flattening and required reinforcement with concrete-encased steel rods. A decade later, mesh was hung below the dome to catch bits that might come loose.
The main problem with the dome was that it expanded when the sun heated the materials, and contracted when they cooled at night. All the movement caused cracks. The cracks allowed rainwater to seep through. And the water slid down the inside of the walls, causing all kinds of damage.
Insulation added in the 1970s moderated temperature swings, which helped for a while.
But a waterproofing membrane installed in the 1990s eventually ruptured, allowing water to soak through the insulation.
“We realized we had to get back to base and start over,” said James Patterson, the cathedral’s director of facilities and capital projects.
Even after all the care lavished on the dome, it’s still considered only temporary, Patterson said. The plan is still to build a spire one day. But that won’t happen anytime soon, he added.
“We are talking hundreds of years from now,” he said.
By: Jane Margolies
BBC-NEWS-SRC: http://www.nytsyn.com/subscribed/stories/6534399, IMPORTING DATE: 2023-01-17 23:00:07
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