Massachusetts Historical Commission - 2009 Preservation Award Winners
Plymouth Rock Portico • Plymouth
 
Plymouth Rock Portico • Plymouth

Rehabilitation & Restoration

The Classical Revival-style Plymouth Rock Portico was built over the famous rock in 1921 to honor the 300th anniversary of the landing of the Pilgrims. Designed by the prominent architectural firm of McKim, Mead, and White, the portico’s features include a magnificent Guastavino-tiled dome. The structure’s waterfront location and open design had allowed seawater to penetrate inside and below the building at high tides. Over time, saltwater combined with other environmental factors to cause extensive surface and structural damage. Little mortar remained between the granite blocks, and decomposing tiles were falling from the dome. Conditions required the installation of a large net under the dome to catch falling tiles and prevent injury to tourists and staff.

The restoration of the Plymouth Rock Portico has returned the structure to its original aesthetic intent and has corrected significant structural problems. Mortar analysis was conducted to determine appropriate mortar replacement, with specific formulas for tidal and non-tidal areas. The granite was completely cleaned, and copper scuppers were replaced to ensure proper precipitation drainage. Restoration of the Guastavino dome involved custom manufacturing of matching replacement tiles, which required four test firings. Newly restored, the Plymouth Rock Portico has been ensured a place of continued prominence on the Plymouth waterfront, where it will continue to greatly benefit area tourism.

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