Historic Structure Weatherization Retrofit – Thetford

Case Studies

Historic Structure Weatherization Retrofit – Thetford

Community overview

Thetford, with a population of 2,588 people, is comprised of five villages: Thetford Hill, Thetford Center, Post Mills, North Thetford, and Union Village. There is a strong ethic of both natural and architectural resource preservation to help preserve the town’s character. The focus of this weatherization and retrofit project was the Thetford Center Community Center, a historic schoolhouse that serves as the location for a variety of events including community suppers and town recreation activities. The project was undertaken to weatherize and retrofit this in-use historic building, to make it more energy efficient.

Tools you can use

A partnership between the Sustainable Energy Resource Group (SERG) and the Thetford Energy Committee catalyzed the weatherization project for the Thetford Center Community Center (TCCC), which started in 2009 and took a year to complete. Because the TCCC is a historic building, the groups engaged historic preservation experts early on, including the Preservation Trust of Vermont and the state’s Division of Historic Preservation, to assess and design energy efficiency implementation strategies. The success of this project was the result of many volunteer hours, and funding from a variety of sources.

The main motivation behind the project was to preserve the historic building, and reduce energy costs. The anticipated energy savings from the weatherization project are 70% over the previous year’s energy costs. This was achieved by performing work that included:
Reducing air leakage by almost 80%, as demonstrated by blower door tests.

  • Installing 2” of foam insulation on basement walls, 16” of cellulose in the attic and dense-packed cellulose in the walls.
  • Installing a curtain drain to keep moisture out.
  • Restoring parts of the foundation that were failing.
  • Installing 150 CFM bath fan with motion controls to ventilate building when in use and help maintain healthy indoor air quality.
  • Installing a new high-efficiency sealed-combustion furnace, to further reduce fuel use and assure proper ventilation of combustion gases.

Because it is a historic building, certain precautions had to be taken when updating the existing construction. For example, a historic preservationist trained volunteers to refurbish the building’s windows onsite. This both improved the building’s efficiency by reducing leaks and taught volunteers to do the same work on their home’s windows—while going about the process in a careful and historically appropriate manner.

Overall, the building gets far more use from the community as a result of this effort because the retrofit made the space more comfortable. In this way, weatherizing a historic building is a way to keep it in use, since if a building is too cold, expensive, or uncomfortable to use, a building – even a historic one at the center of a community – is likely to fall into disrepair. This project serves as a model for how other Vermont communities can make energy efficiency improvements on beautiful, old buildings while preserving their historic character.

Lessons learned

  • The support of the Thetford Selectboard, as well as generous support from a variety of organizations and individuals, was vital to the success of this project.
  • Making sure volunteers received technical assistance from energy efficiency experts as they undertook their work ensured they were making the improvements correctly.
  • The project leaders consulted with historic preservationists early in the process to take historic features into consideration while making efficiency improvements.

Contact: Robert Walker, Sustainable Energy Resource Group (SERG), SERG@valley.net, 802-785-4126

Related tools:
• Weatherizing Town Buildings

Related Issues:
• Historic Preservation
• Energy Solutions for Communities


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