Solid as a Rock

The historic portico in Plymouth, Mass., gets a much-needed makeover

There was always something mysterious about the way the vaulted ceiling of the Plymouth Rock portico seemed to defy gravity. Then one day in 1998, nearly 80 years after the Classical Revival structure was completed, part of the terra-cotta ceiling clattered to the floor. Would the rest follow? No one knew, because the construction technique used to build the portico ceiling had essentially been forgotten.

The state agency that maintains the handsome structure, built in 1921 to commemorate the 300th anniversary of the Pilgrims’ landing at Plymouth, 40 miles southeast of Boston, took the precautionary measure of draping black netting beneath the ceiling—protecting visitors who came to see the most symbolic rock in America down below. "The netting looked like a diaper," remembers Shaun Provencher, preservation planner with the Massachusetts Department of Conservation and Recreation. And it was still up six years later, when the department finally found state funding for engineering tests. Before a full-scale restoration could take place, however, experts needed to know more about that tile ceiling.

The man credited with its design was a Spanish architect and builder named Rafael Guastavino. He moved to New York City from Barcelona in 1881, with the idea of updating a 600-year-old vaulting technique he had learned on the Mediterranean coast of Spain. Guastavino’s patented "tile arch system," which featured thin terra-cotta tiles buttered with mortar and sandwiched together in layers, was as strong as reinforced concrete, but had an Old World charm. "He was like a master builder from medieval times who landed in 19th-century America," says MIT engineering professor John Ochsendorf, author of the forthcoming book Guastavino Vaulting: The Art of Structural Tile.

Guastavino teamed up with the top architects of his day, including those at McKim, Mead & White, designers of the Plymouth portico. When Guastavino’s company closed in 1962, it had built soaring vaults—at once structural and decorative—in more than 1,000 buildings in North America, including the Boston Public Library, New York’s Grand Central Terminal, and the Biltmore Estate in Asheville, N.C. But by then, concrete had eclipsed tile as a preferred building material, and Guastavino had been forgotten.

On a cold day in January, standing amid the portico’s Tuscan columns with Plymouth Bay just below, Jack Glassman pulled a buff-colored tile from his parka pocket and tapped it with an acrylic hammer. Glassman, director of historic preservation with the firm Bargmann Hendrie + Archetype, Inc., oversaw the technical aspects of the restoration. The tile he held was a discarded original from the ceiling above, the hammer a diagnostic tool used by masonry experts to check for loose tiles.

Removing and replacing tiles was only part of the restoration challenge. Glassman also had to stop what was causing the tiles to pop free—water seeping into the roof and rusting the steel reinforcing beams at the ceiling’s edge. That meant repointing granite blocks around the top of the portico and replacing copper scuppers to direct rainwater away from the roof.

Persuading the state to allocate $490,000 to make these structural and cosmetic improvements wasn’t easy, but Provencher says the real challenge was marshaling the interested parties—state agencies, local selectmen, the visitors bureau, and the public. All agreed that restoration work was imperative—they were just nervous about its effect on tourism: More than a million people visit Plymouth Rock each year, with dozens of tour buses lining up in the weeks leading to Thanksgiving. Would ongoing construction keep them away? In the end, after much outreach on the part of Provencher’s office, everyone got on board. "It snowballed in a good way," he says.

Despite its popularity, or maybe because of it, Plymouth Rock is, for some, anticlimactic. "People come here expecting to see the Rock of Gibraltar," Provencher says. "They walk up to the railing and say, ‘Where is it?’ " Now that the protective netting is gone and the portico’s pomp and granite-columned glory has been fully restored, he hopes that visitors will be awed by Guastavino’s crisp, herringbone-pattered vault. "For 90 years you’ve had people coming here and looking down," he says. "We want them to start looking up."

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