Blog Post

Mid-Century Modern Structures: Materials and Preservation

A symposium organized by the National Center for Preservation Technology, the National Park Service, and World Monuments Fund, April 13-16, 2015, St. Louis, MO

Modern structures are subject to the same risks as older structures, including neglect, inappropriate renovation, the effects of climate change and even demolition, but additional risks arise from the very qualities that make them modern: innovative technologies, experimental materials, and novel design. The lack of understanding that buildings of our own time can be important enough to be kept for the future, or that modern buildings might need the same care as older structures, may be the greatest challenge.

World Monuments Fund’s concern for modern sites began in the 1980s, and the establishment of WMF’s Modernism at Risk Initiative, launched in 2006 with founding sponsor Knoll, allows WMF to take a more active role in addressing the distinct threats facing great works of modern architecture around the world.

The iconic St. Louis Gateway Arch, a symbol of midcentury modernist architecture designed by renowned architect Eero Saarinen, was included on the 2014 World Monuments Watch because of concerns of the apparent corrosion and staining on the stainless steel structure. In 2004, the National Parks Service initiated an investigation into these causes, which culminated in an inspection of the heretofore inaccessible upper reaches of the Arch in October 2014. A final report was published in April 2015 and the findings were presented at the symposium "Mid-Century Modern Structures: Materials and Preservation," organized by the National Center for Preservation Technology, the National Park Service, and World Monuments Fund. The report reveals that the exterior staining is an aesthetic rather than structural issue, resulting from the collection of significant airborne pollutant particles on the Arch during its first decades of existence. In ensuing years, the industry and highways, which were the source of these pollutants, were removed and the soiling rate is consequently much reduced.

The timing and location of the symposium were chosen to commemorate the 50th anniversary of the Arch, completed in 1965. Presentations and panels focused not only on the findings of the studies of the Arch, but also on the unique needs of preserving materials used in mid-century modern architecture and best practices in their ongoing care and maintenance.

The symposium opened with an evening lecture by Susan Saarinen, landscape architect and daughter of Eero, and Ken Kolkmeier, who worked as project manager during the construction of the Arch. Presentations also included preservation and restoration challenges at other notable modern sites, including two additional WMF Watch sites, the Chinati Foundation, and Philip Johnson’s New York State Pavilion.

David Bright, Senior VP of Communications at Knoll, Inc. discussed our special initiative "Modernism at Risk," and illustrated WMF’s efforts to support advocacy for, conservation of, and public education on the value of modern architectural heritage

The symposium concluded with a tour of commercial, residential, and religious modern structures in St. Louis. For more information on the symposium, including a full schedule, see