Bennington Battle Monument study finds heavy moisture; multi‑year drying and repair plan proposed

State Historic Preservation Officer Laura Trisham and Jamie Duggan, director of preservation at Vermont State Historic Sites, told the Senate Institutions Committee on Feb. 11 that a multi‑year preservation effort is needed at the Bennington Battle Monument after a multi‑year technical study found the structure heavily saturated with water and continuing to shed stone.

Trisham said the monument is “stable” and “not going to tip over,” but engineers estimate the masonry could be holding as much as 66,000 gallons of water and the team has documented about 1,300 instances of failed mortar requiring repair. Trisham said those conditions make drying the monument before any exterior or interior repairs essential: “Drying out the stone interior and exterior is a priority prior to any repairs because they will fail if we do not dry out the monument first.”

Why it matters: The monument is Vermont’s tallest man‑made building, draws thousands of visitors and supports a busy gift shop; the site also carries FAA lighting and public access considerations. Officials said failing to begin a comprehensive program now will increase future repair needs and costs.

What the study found and the next steps Jamie Duggan described the technical work: coring, crack monitoring, petrographic analysis of the Hudson Falls (Sandy Hill) dolomitic limestone, laser scanning and season‑long environmental monitoring. The testing showed multiple crack patterns within individual stones and moisture‑driven expansion and contraction that have caused the stone to delaminate in places.

Duggan and Trisham said the recommended immediate work is the design and erection of a building‑enclosure/scaffold system — effectively a full‑height protective enclosure with weatherproof scrim — plus a controlled dehumidification campaign to remove moisture slowly. Duggan said that design work must come first because the engineering of the enclosure will determine foundation and footing needs for the scaffolding and thus the project’s larger costs.

Costs, timeline and funding Trisham and Duggan said phase 1a and 1b — the enclosure design, geotechnical work, archaeology, and initial drying system installation and bidding — are expected to take roughly three years. Public remarks in the meeting cited example scaffold/enclosure costs in the millions: Duggan referenced prior large‑monument scaffolding projects and suggested the erection of a custom enclosure could cost in the mid‑single‑digit millions to low‑double‑digit millions, with planners also citing an illustrative $40 million total projection that officials said is not final and will be informed by the phase‑1 design.

Trisham said the division has secured conversations with the federal delegation and has obtained $500,000 in congressionally directed spending from Senator Bernie Sanders; she said that money has not yet been expended and would be allocated to archaeology, seismic monitoring and vertical‑access work. Trisham said other federal conversations have included senators Patrick Leahy and Peter Welch.

Public safety, interim measures and community access Officials described interim safety steps already taken: a perimeter fence and a covered walkway to protect visitors and staff, and contracted vertical‑access teams that have removed loose stone and provided a geo‑referenced photographic record of the exterior. Trisham said staff will keep the monument open as long as it is safe, and that they plan community outreach and remote viewing so the public can follow work while scaffolding or enclosures are in place.

Operational and revenue context Trisham told the committee visitation to the monument’s interior was approaching levels not seen since 2002 — nearly 40,000 annual visitors to the paid exhibition level — and that the onsite gift shop generated about $276,000 in revenue in the most recent reporting year. She said elevator failures and computer control problems have been tied to the high moisture levels inside the monument.

Maintenance and monitoring Officials recommended establishing a cyclical maintenance and monitoring program. Trisham said an initial annual monitoring and maintenance cost estimated for the first year is about $158,509 (largely driven by monitoring setup), with much lower recurring annual costs thereafter (Duggan cited a figure roughly in the low‑to‑mid five figures for ongoing monitoring once systems are established).

What lawmakers asked Committee members pressed for timelines and for the division to return with more detailed budget line items informed by the phase‑1 design. Senator Rob Hong, vice chair and committee chairing member, and other senators emphasized the monument’s importance to Bennington and the state and asked that preservation teams coordinate with local partners.

What remains undecided Officials said the precise total cost and the final implementation schedule depend on the design and mock‑up testing planned in phase 1b; they cautioned that delays will likely increase the scope of stone replacement required.

Ending Trisham said staff plan to continue monitoring the monument and to engage the community as design work proceeds. “We will be opening this year,” she added, while also warning that the full preservation work will be multi‑year and will require multiple funding sources.