Overview of Restoration Work
As the stewards of this iconic monument, the National Parks of Boston is taking action to preserve the Bunker Hill Monument to prevent additional and possibly irreparable damage.
In this project, workers will replace the mortar on the pyramidion roof and on the upper levels of the Monument. This work will prevent further leaks into the Monument; these leaks have led to the breakdown of mortar, deterioration of masonry, and slippery conditions in the stairway. This work on the Monument is necessary every 20 - 30 years.
In order to conduct this work, scaffolding will cover the entirety of the Monument. To put up and subsequently take down the scaffolding will take several weeks. Once the scaffolding is assembled, work can begin on the pyramidion.
This work is anticipated to conclude before the end of 2023.
What is a Pyramidion?
A pyramidion is an equally sided pyramid that tops an obelisk. The Bunker Hill Monument's pyramidion serves as the roof of the Monument. About twenty granite blocks make up the exterior of the Monument's pyramidion, adding thirteen feet to the height of the Monument. Though the pyramidion's blocks make up a small fraction of the 3,000 blocks used to construct the Monument, they play a crucial role. These blocks help protect the Monument from the elements, like any roof does. The Monument's pyramidion also has a distinctive capstone, the very top of the Monument. This 2 ½ ton triangular granite block, the weight of a small car, was the last block hoisted into place when workers completed the Monument in 1842.
Current State of the Pyramidion
Just like the rest of the Monument, workers constructed the pyramidion out of granite blocks and mortar. Mortar is composed of cement and sand; it helps bind the granite blocks together and protects against weather. Over the years, the mortar near the outside surface of the granite blocks breaks down. Though the granite blocks are still bound together, gaps in the mortar leave the Monument vulnerable to the weather.
The slow deterioration of the mortar between the granite blocks in the pyramidion has led to water leaking into the Monument. This seepage has resulted in stains on the walls, floor, and dome of the observatory, the open space at the top of the Monument where visitors can enjoy a view the surrounding area. Water also washes out mortar between the granite blocks and causes damage to the masonry when it freezes and thaws.
The water leaking into the Monument through the pyramidion has also impacted the stairway. Slippery conditions on the stairs have resulted in Monument closures for visitor safety.
At 180 years old, the Bunker Hill Monument requires regular maintenance so it can remain preserved for many years to come.
What Can Visitors Expect?
This preservation work will affect the Bunker Hill Monument Grounds from July 31 through the end of 2023.
Visitors will be able to access the Monument grounds outside of the construction zone fencing. The National Parks of Boston plans to keep the Monument open as often as possible during this project, while also recognizing that construction and restoration work may cause the Monument to close without notice. When the Monument is open, a covered path will lead visitors from the Monument grounds to the Bunker Hill Lodge. Here, visitors will be able to enter the Monument.
Please note, the view from the Monument observatory windows will be obstructed due to scaffolding and scrim. Scrim is mesh netting, almost resembling a large cheese cloth. The Scrim will be wrapped around the scaffolding as a safety measure to protect construction crews and visitors. Visitors can view live footage from the top of the Bunker Hill Monument by visiting Views of the Revolution: 360 Monument Webcams.
Historical Significance of the Monument
Commemorating the first pitched battle of the American War for Independence in 1775, Bunker Hill Monument has stood as a symbol for the nation’s hope and possibility since its opening in 1843. For generations, people have visited the Monument to remember and reflect on the motivations and enduring legacies of those who fought in the Battle of Bunker Hill.
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Source: U.S. Department of the Interior, National Park Service