An engineering report reveals $40 million needed for Bennington Monument restoration in Vermont. The 306-ft obelisk faces significant water-related damage, requiring costly repairs and enclosures. Past repairs deemed substandard and urgent funding needed for preservation efforts.
Vermont State Historic Sites photo
An engineering assessment of the Bennington Monument in the village of Old Bennington, Vt., poses a challenge.
An engineering assessment of the Bennington Monument in the village of Old Bennington, Vt., poses a challenge not unlike the one that drew hundreds of Patriots to this area in 1777 to fend off a British attack.
This time, however, the enemy is not a contingent of Hessian or British soldiers but a joltingly high estimate for what is envisioned as a multi-year project to restore and preserve the 306-ft. stone obelisk into the future.
The Bennington Banner reported Feb. 10 that in briefing state lawmakers, preservation officials have referred to a total cost estimate of roughly $40 million to reverse weather-related damage and up to $10 million just to enclose the structure and dry out the stone blocks to allow maintenance and repair work.
"It is truly a monumental project," said state Rep. Mary Morrissey, a member of the Vermont House Committee on Corrections and Institutions, which heard from the state preservationists earlier in Feb.
She said it is likely the local delegation will meet or otherwise discuss the situation, which could negatively affect the historic monument and its significance to both Bennington and Vt.
Built in the late 1880s and dedicated in 1891, the Bennington Monument commemorates a pivotal victory for American forces during the Revolutionary War. On Aug. 16, 1777, Vt.'s Green Mountain Boys, the N.H. Militia and volunteers from Mass. combined to defeat British troops charged with capturing provisions stored at the Bennington military supply depot, located on the site where the monument stands today.
Obelisk's Stone Work ‘Saturated' With Water
A report released in January 2025 by a team of engineering firms working with the state to identify the problems and pose the next steps represents the second phase of the process, the Banner noted.
Earlier, phase one involved assessing the severity of the damage such as cracks in the stones and loss of grout between the blocks, along with deterioration of stairs and other features inside the monument.
Stevens & Associates in Brattleboro, Easton Architects, based in New York City; and Silman Structural Solutions (now part of TYLin) are working with the Vermont Department of Building and General Services to lead the preservation, restoration and conservation project.
According to the recent report, "The primary objective of phase two was to complete additional recommended scopes of work to further identify the architectural, material and engineering conditions of the [Bennington] Monument as it stands today."
The comprehensive study included:
• in-depth stone testing and mortar analysis,
• extraction of stone cores and samples,
• petrography,
• a building enclosure and hygrothermal review,
• a mechanical engineering preliminary assessment,
• water infiltration and IR testing,
• an architectural preservation review and analysis,
• masonry strength testing,
• a structural finite element analysis,
• a lightning protection and grounding assessment,
• a preliminary geotechnical investigation,
• additional electronic crack and moisture monitoring, and
• a non-destructive evaluation carried out via rope access for documentation.
The condition of the stone blocks used in the construction of the monument more than 135 years ago was a prime focus of the assessment, the Bennington news source added.
According to the just released phase two report, the stones have absorbed thousands of gallons of water, which has resulted in damage and deterioration to the obelisk. The study noted that tests determined the structure's walls are "saturated" with moisture.
"The original stone used to construct the monument may not have been the optimal choice for this type of structure," the analysis read. "The stone was identified as dolomitic stone and is a harder and stronger stone than calciferous limestone, but it is nevertheless a sedimentary stone that is porous and permeable, [making it] susceptible to moisture migration and freeze-thaw damage."
In addition, the engineering study noted, "We recognize that this is not something that can be changed about the monument. Preliminary analysis suggests that the strength properties of this stone may not be a primary concern, but rather the vulnerability of the stone to moisture-related processes will need to be further understood to identify an effective restoration strategy."
Past Repairs Have Proven to Be Substandard
Numerous repair efforts have been performed on the Bennington Monument dating as early as 1907 to address persistent issues of humidity, water infiltration and moisture inside the obelisk, the engineering team said.
They added that until the phase one study, completed in 2022, there had not been a full assessment of the structure "to understand the mechanisms of deterioration of the masonry walls." Nor had there been any "testing and analysis of materials in order to develop appropriate repair techniques and perform effective, full-scale repairs."
Previous repointing and mortar repair work "focused on the exterior and interior of the upper third of the monument," the report continued, while some replacement mortars used "were too hard for the masonry, leading to cracking," and the work "did not meet contemporary conservation standards, particularly caulk repairs, and hard cementitious repairs."
Many of the structure's cracks were previously repaired by in-filling with a bead of sealant. Other fixes included cementitious mortar repairs in wider cracks and epoxy injection repairs in narrower ones.
Experts also reported that the monument has no heating, ventilation, or air conditioning systems within it, although an old, unused steam-fed heating system still exists.
Steps Recommended to Dry, Repair Monument
The Banner noted that among the recommendations in the phase two report are adding dehumidification and ventilation systems to dry the stone tower's interior, install a heat source, such as a fuel-fired boiler located off site that would pump stream or hot water to the structure, along with geothermal heat pumps.
Designing the recommended weather-tight obelisk enclosure to allow for drying the structure and performing repairs has been estimated to cost from $5 million to $10 million, part of the estimated $40 million to fully restore and preserve the Bennington Monument.
The enclosure, once designed, is estimated to require eight to 12 months to install and would be in place from three to six years.
Addressing the monument's condition, state Sen. Rob Plunkett said, "I think it is important to emphasize that there is no imminent peril, but dedicating ourselves to finding a path to funding the project is crucial."
Plunkett also serves as vice chair of the Senate Committee on Institutions, which considers issues concerning state lands and buildings.
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