It’s difficult to miss a 5-foot crack in a 12-foot span of glass.

And it was one of the last things that Kinney Frelinghuysen, director of Frelinghuysen Morris House and Studio in Lenox, Massachusetts, wanted to see.

The preservation of the house, once occupied by abstract artists Suzy Frelinghuysen and George L. K. Morris and now part of the National Trust's Historic Artists' Homes and Studios program, is more than just a professional matter for Kinney. As a nephew of Frelinghuysen, Kinney knows how much the place meant to his aunt. Her and her husband's Cubist frescoes adorn its interior, but the largest work in the collection is the house itself.

About 12 frescoes decorate the interior of the building, in addition to several on the exterior. Morris handled the living room ones, while Frelinghuysen created the six located in the dining room. Four of those six demand your attention as you enter the room, and the other two can be found in alcoves behind shelves of antiques—glass bowls, a statue of Buddhist goddess of compassion Guanyin, and china that matched the frescoes’ color scheme.

Kinney remembers the antiques fondly from his many visits to the house as a child. “The artist loved to combine antiques with the modern setting […] I always felt that was part of the workings of the room. The murals were integrated with the brass fireplace and these shelf objects. The room had a unity to it, a harmony to it,” he says.

Aunt Suzy was a distant-enough relative for Kinney to feel free to discuss matters he wouldn’t have with his parents. When he decided to commit to painting as a young adult, he was inspired by her works. And when Frelinghuysen passed away in 1988, it was Kinney who served as her executor. The house took on a different meaning to him then.

“It started saying, ‘I’m this big, bold, white block and I don’t compromise, and nature doesn’t compromise, but we complement each other,’” he says. “Somehow it seemed very natural for me to want to be there and watch over the place.” Ten years later, the building was reborn as a house museum, under the stewardship of Kinney and his wife, Linda.

When they began transforming the structure from livable to tour-able, the bones of the structure seemed sturdy. But, as is often the case, the biggest issues are the ones that are hardest to detect early.

The 5-foot crack appeared one day in 2013. The glass pane in question was part of a sliding door connecting the dining room and an outdoor marble ledge. At first, Kinney and the rest of the staff were perplexed. What could have caused such a large fracture?

Eventually, they realized the crack was a symptom of weakness both above and below. A hipped roof added in the 1950s increased the pressure on the slider's steel header. Decades of 20-person tour groups pacing around Suzy’s bedroom directly above conspired to further strain the beam. Meanwhile, water had seeped beneath the marble patio, rotting the bases of some wooden studs.

The result? One giant crack, and many high-priority repairs.

“What seemed to be a very strong piece of steel was not adequate for the job,” Kinney says. “It all came to a head with that cracking of the glass.”

The signs had been easy to miss; lacking blueprints, no one knew that the house even contained any steel components. Regardless, the problem at hand needed to be addressed. Over the next few years, the team brought in structural engineers to devise a plan of attack.

Replacing the weakened beams and posts that had caused the giant crack would require sawing through two inches of stucco and sheathing. But the location of the two smaller frescoes in the dining room alcoves made the difficult job even harder. If the process of cutting through the wall vibrated the 80-year-old frescoes too violently, they would crumble. No one was sure exactly how much shaking they could take, and no one wanted to find out.

There was no true solution except to watch and hope. Staff members observed the frescoes and placed their hands on the wall during the cutting, yelling over the din at the craftsman to stop whenever it felt too intense. To everyone’s relief, the frescoes held. Contractors could proceed with the rest of the repairs, replacing the rotted wall studs with stainless steel posts and inserting a flitch beam above the glass for additional support.