Featured, Preservation

Restoring the Painting Gallery Roof

Designed by Philip Johnson and constructed in 1965, the Painting Gallery is an earth-berm structure, a modern interpretation of the ancient monument, the Treasury of Atreus in Mycenae, Greece. Shaped roughly like a cloverleaf, the structure resembles a large grassy mound on the outside with concrete roof deck forming a cap on top. The building houses Johnson’s earthly treasures and an important part of his legacy: his art collection. This collection tells the story of Johnson as a patron of the arts, as well as the story of his relationship with his partner, David Whitney. Johnson had been involved with The Museum of Modern Art since its establishment in 1929, but after meeting David Whitney in 1960, Johnson became an avid art collector.

Preservation Challenges

The advantages and challenges of maintaining an art gallery housed in an earth-berm building were revealed early on. In a 1979 interview with the New Canaan Historical Society, Johnson remarked, “There is enough earth to give it insulation, and the advantage, of course, is that it is always cool; the disadvantages are that you are in a basement, and you know the inherent problems of a basement that contractors don’t tell you about when they build for you. Moisture.”  (Interview with Philip Johnson, New Canaan Historical Society, June 24, 1979.)

Before the site opened to the public, the National Trust undertook environmental stabilization, cleaning, and maintenance of the interior of the Painting Gallery, as well as the active conservation of its collections. The negative effects of deferred maintenance were obvious. Moisture infiltration and inconsistent temperature and humidity levels had resulted in mold growth on walls, exhibition panels, and several artworks. In addition there were cracks in the plaster wall surfaces, salt efflorescence in the terrazzo floor, and oxidation of the bronze floor joints. To bring the building up to public museum standards, a security system was added, and a consistent 50 to 55 percent humidity level was finally achieved in February 2007. Throughout the inaugural tour season in 2007, Glass House staff scheduled in-situ art conservation projects to showcase the site’s commitment to conservation and preservation. The curatorial thesis was “conservation as exhibition.”

Once the interior of the Painting Gallery was stabilized, it became clear that the building’s exterior envelope was compromised as evidenced by persistent staining, blistering, and flaking of the plaster ceilings and concrete walls. A review of the original construction documents and other records revealed piecemeal repairs to the sub-grade waterproofing system over the years. Several test pits were dug to further examine the waterproofing on the rising walls of the building and the limited areas of sub-grade concrete roof deck (at the vestibule, bar, bathroom, and mechanical room). Although the original rubber roofing membrane on the above-grade portion remained intact, it was at the end of its useful life, and the National Trust decided that the best course of action would be to replace it. Glass House staff brought waterproofing and roofing product specialists and manufacturers to the site help determine the best construction practices and products currently on the market.

The unique features of the building and the valuable collection it houses added significant layers of complexity to the project. First, the roofing membrane was held in place by 50 red coping stones, each weighing from 1,000 to 1,500 pounds. In order to replace the roofing membrane, these stones would have to be removed with a crane, stored on the site, and then returned to their exact location on the roof once the new membrane was in place. Second, the individual pieces that compose the valuable art collection inside the Painting Gallery were large in size and, in some cases, were complex multi-media compositions. Deconstructing these works in order to remove them from the Painting Gallery would have risked damaging or de-valuing them, so the National Trust decided that the pieces would remain in the gallery during construction and would be protected in place.

Due to the public nature of this project, a thoughtful communication plan was essential to managing expectations of neighbors, the community of New Canaan, and site visitors.

After careful internal deliberations and discussions with the contractor, public tours were allowed to walk along the perimeter of the construction site and to enter the Painting Gallery. Once inside, visitors could watch a video of the artwork, since the art collection was wrapped and otherwise protected from dust during construction. A virtual tour was also created to allow visitors to the site and online visitors to “walk through” the building and to view the collection.

Before construction began, and then on a weekly basis during the project, the guides and visitor center staff were provided with a detailed schedule on the scope of work and a diagram of the mobilization and staging areas that clearly indicated the tour path. This communication plan was critical to the project’s success, creating an engaging visitor experience and learning opportunity about the preservation of an iconic Modern structure.

Project Team

Mary Kay Judy – Architectural & Cultural Heritage Conservation

Robert Silman Associates, New York

Nicholson & Galloway


The Painting Gallery roof replacement and the berm restoration were made possible in part by a matching grant from the Historic Sites Fund. The Historic Sites Fund is endowed in part by grants from the National Park Service and the National Trust’s Gifts of Heritage Program.

Related Content

  • Brick House Restoration

  • Bloomberg Connects

  • Breath of Life:
    The Art of Charles Ethan Porter

  • Philip Johnson Biography