Of the 49 acres that make up the New Canaan, Connecticut, enclave of architect Philip Johnson, 1,815 square feet belong to his Glass House. The rest of the compound, added after 1949, is an architectural laboratory comprising 13 multifarious buildings, like the Sculpture Gallery, a skylighted showcase for Johnson’s art collection, which he briefly considered making his home once it was finished in 1970.

It was his high regard for the space that motivated a fastidious restoration by the National Trust for Historic Preservation last year. Months of touch-ups targeted a brewing crisis: Water had begun to penetrate the gallery’s distinctive skylights. A replacement system, donated by Oldcastle BuildingEnvelope, mimics the exact interplay of light and shadow that was created by the original. The sculptures, including work by Robert Rauschenberg, Frank Stella, and others, will be safely reunited under its roof this October.