Plymouth Rock Portico
An Icon Is Preserved
Following two years of planning, testing, and design, the Department of Conservation and Recreation (DCR) is embarking on a comprehensive rehabilitation of the Plymouth Rock Portico. DCR apologizes for any inconvenience to the public caused by this preservation project. However, the work is necessary to ensure many more years of public enjoyment of both the Portico and Plymouth Rock.
History of the Portico
Plymouth Rock rests on a significant historic site where, tradition tells us, the passengers on the Mayflower first made a permanent home in North America in 1620. But the Portico covering Plymouth Rock is itself an historic monument. The Neo-Classical structure was designed by the highly influential architectural firm of McKim, Mead and White and built in 1921, replacing an earlier Gothic-style monument. At that time, many significant buildings across the United States, such as libraries and government centers, were built in the Neo-Classical style to suggest permanence, stability, and strength. Almost fifty years later, in 1970, the Plymouth Rock Portico was listed in the National Register of Historic Places.
What Happened to the Portico?
While the Portico appears to be built from solid granite, it actually contains mortar, terra cotta tiles, and other materials. These are all reinforced by steel beams inside the masonry at the dome's edges. Over time, the mortar between the granite blocks around the top of the Portico has deteriorated. This has allowed water to seep into the structure and cause the interior steel beams to rust and expand. As a result, the surrounding mortar and tiles have crumbled and begun to fall, the exterior of the Portico is being stained by water flowing in and out of the mortar joints, and other associated structural and cosmetic problems have arisen.
Ongoing Rehabilitation Activities
Repairing past damage and preventing future problems with the Portico are the main goals of this project. Due to the historic significance of the Portico, DCR is proceeding with caution, removing as little historic material as possible, and adding as little modern material as possible. The work you see before you includes cleaning rust from the internal steel, replacing damaged tiles with custom-made and historically appropriate copies, cleaning all the granite masonry, replacing failed mortar joints, and replacing the roof. As an added precaution, DCR is installing a "cathodic protection" rust-prevention system. This involves connecting a safe, mild electrical current to the internal steel frame, which halts the chemical process that causes rust. This method has protected pipelines and ships for many years, but has only recently been used to protect historic structures in Europe and the United States. The end result of all this work will be a structurally stable, but visibly unchanged, Plymouth Rock Portico.
What do the Portico, Ellis Island, and the Boston Public Library have in common?
The Portico's vaulted, terra cotta tile dome is based on a traditional Spanish method of building called "Catalan vaulting," which was adopted in the United States at the turn of the century by the Guastavino Company, a firm based at the time in Woburn, MA. Their distinctive constructions are found in a number of famous American buildings, such as the Great Hall at Ellis Island in New York, the Boston Public Library, and the addition to Pilgrim Hall in Plymouth.
March 24 – June 30, 2008
Portico Closed for Rehabilitation
July 1 – September 28, 2008
Visitors will be able to view Plymouth Rock through a viewing corridor.
October 1, 2008
Portico rehabilitation completed.
Agency: Department of Conservation and Recreation
DCR Contact: Shaun Provencher 617 626-1376
Architects: Bargmann Hendrie + Archetype, (BH+A) Boston, MA
Contractor: Chapman Waterproofing Company Boston, MA