Photograph ©Elizabeth Felicella

The window walls on the west and north sides of the gallery building were an important part of Kahn’s design. But they had been plagued by problems from the beginning, particularly in the winter, when condensation caused the steel window frames to rust. The seals on the double-pane glass were prone to breakage, allowing moisture between the panes and resulting in many permanently fogged windows. What’s more, the glass offered insufficient protection against heat and sunlight, so curators had resorted to heavy curtains to protect the art inside. Taken together, these problems wrecked Kahn’s vision of a transparent, luminous wall.

In the new design (pictured), which duplicates the appearance and dimensions of Kahn’s original detailing, the steel has been replaced by aluminum, and the frames are designed to prevent outside heat and cold from passing to the inside. The new glass keeps out a great deal of heat and ultraviolet light, so that only translucent scrims are needed in the painting galleries.