Les Quatre Saisons (The Four Seasons) mosaic by artist Marc Chagall, was created as a gift to the people of Chicago by the artist and constructed in 1974 with funding by the Prince Charitable Trust. The mosaic consists of tesserae placed on precast concrete panels, which are mounted on a cast in place concrete structure, and is approximately 70 feet long by 14 feet wide by 10 feet tall. The mosaic is located at Chase Tower Plaza (formerly First National Bank of Chicago Plaza) in Chicago, Illinois. Stewardship of the mosaic is overseen by a consortium of Chicago arts entities including the Art Institute of Chicago
Due to its installation in an exterior environment and the materials and methods selected for its initial construction, the mosaic is highly susceptible to distress related to weather. Since its installation, several projects have been initiated to clean, repair, and monitor the mosaic. The first repair project commenced in 1988, fourteen years after the mosaic was installed, after extensive deterioration of the walls and original mosaic top surface was observed. At that time, large areas of the walls were restored and the top was replaced with granite panels. Following further deterioration observed in the 1990s, WJE conducted an investigation and laboratory studies, and developed the design of repairs implemented in 1993.. In addition, a canopy featuring a glazed roof to allow light to enter the space below, and open sides to preserve the immediacy of the viewer experience, was constructed to protect the mosaic.
WJE has had an ongoing relationship with the mosaic since performing the assessment and repairs in the early 1990s, including vibration monitoring during repairs to the adjacent plaza and monitoring during the recent micro-abrasive cleaning of adjacent Chase Tower. Since completion of the 1993 repair program and construction of the protective canopy, only minor repairs and gentle cleaning have been required to the mosaic. Most recently, WJE conducted a condition assessment (2010) and performed cleaning the walls of the mosaic and the reinstallation of a few delaminated tesserae (2011).
This presentation will explore the original materials and methods of the mosaic’s construction and the role of environmental and physical site conditions in the creation of early-forming distress conditions, as well as the results of repair methods used in the 1980s. The investigation approach and methods as well as the analytical methods used to develop the 1993 repairs will be discussed, along with the investigation findings and recommendations, and the techniques used in the recent repair program. It has been nearly twenty years since the last large-scale repair program, and the 2010‒2011 condition assessment and repair program support the benefits of laboratory studies to guide the 1990s repairs, as well as the effectiveness of the protective canopy. The presentation will also address the monitoring efforts implemented to protect the mosaic since 1993.
