Frank Lloyd Wright’s Fallingwater Is Leaking. Inside the $7 Million Job To Fix It.

For a tall person, visiting Fallingwater—Frank Lloyd Wright’s most famous house—can be a little scary. Wright made the “parapet walls”—the low barriers around the house’s many balconies—much shorter than the 42 inches required by contemporary building codes. 

Wright, at just 5’7,” was unconcerned. But I’m 6’2.” The parapet wall on the house’s upper terrace—which is only 26 inches high—stops right above my knees. Under the terrace is a waterfall that feeds a stream approximately 50 feet below, “depending on which part of its rocky surface you measure from,” says John Matteo, a structural engineer who has worked on preservation projects at Fallingwater since the 1990s.

No wonder I feel queasy as I approach one of the low parapet walls. It doesn’t help that, with snow on the ground during my January visit, I feel like I might slip. And a slip here could lead to a plunge.

Luckily, nobody is known to have fallen in the 90 years since the house was built, according to Justin Gunther, Fallingwater’s executive director since 2018. But there are other things to worry about. The house has leaked in dozens of places over the years, and Gunther is in the midst of the latest effort to make it watertight, a job expected to cost $7 million. That’s about 40 times the cost of building the house in the 1930s.

Clearly, keeping Fallingwater dry—a process that could be called stallingwater—is a challenge. During my visit, the house was enveloped in scaffolding, which was going to allow workers to complete the waterproofing job by April. Then, in early February, the scaffolding contractor, BrandSafway Industries of Pittsburgh, became concerned about the force of the water hitting the base of the scaffolding, which is right in the path of the waterfall.

Work on that part of the scaffolding was halted while the company strengthened the structure. That, Gunther says, caused unexpected delays. A spokesman for BrandSafway declined to comment on Fallingwater. After deliberation, Gunther decided to cancel the tours scheduled for March that were to include access to the platforms—putting visitors in hard hats farther out over the waterfall than any other members of the public, ever.

In December, before Fallingwater closed for an annual 10-week winter break, some visitors were disappointed to see the scaffolding, which made the house almost unrecognizable. But others were fascinated by the work in progress. The Western Pennsylvania Conservancy, which owns the house, witnessed that fascination during another spate of repairs 25 years ago, which, not coincidentally, was the last time I visited the house, in a rural area about 50 miles southeast of Pittsburgh. 

According to Gunther, tickets to the tours that included scaffold access were selling quickly (at $89 per person) before he had to change the agenda. Visitors will still be able to see repair work in progress throughout the house. Completed in 1937 and voted the country’s most significant building by the American Institute of Architects in 1991, Fallingwater attracted more than 143,000 visitors in 2024, Gunther says.

It also attracts a lot of water. Rain and melting snow have been finding their way into walls that, although they appear to be solid stone, are really hollow masonry tubes. When the house was built, their cavities were filled with sandstone left over from construction. But that rubble has been settling for 90 years, leaving room for water to collect before dripping into the house, where it threatens to damage interior finishes, furniture and artworks.

In Gunther’s opinion, the leaks aren’t evidence of Wright’s incompetence, but of his daring. “He was pushing conventional notions of building to achieve something truly extraordinary, and he used the best technologies at his disposal,” Gunther says. “So I wouldn’t say anything was a mistake. Instead, the house’s design presented inherently challenging features to waterproof, such as flagstone terraces that serve as roofs for interior spaces below.” 

But Fallingwater’s preservation architect, Pamela Jerome, of New York’s Architectural Preservation Studio, says that Wright could have called for copper flashing where roofs or terraces intersect walls. The flashing would have kept water from penetrating the walls. But Wright didn’t like seeing a few inches of exposed copper at the base of each protected wall, so he avoided flashing, Jerome says. She says a lack of flashing is a problem at Wright’s Guggenheim Museum, on Fifth Avenue in Manhattan, where she has also been involved in preservation efforts. 

At Fallingwater, the main solution devised by Matteo, Jerome and others is to pump liquid grout into the hollow walls. The liquid grout, in this case a proprietary mix from Maryland-based Masonry Solutions International, was tried—successfully—on the separate guesthouse before work began on the main house. Walls are first scanned with ground penetrating radar to identify voids. The compound is then injected through tiny holes drilled around those voids. When the compound hardens, and the holes in the masonry are filled, it should be nearly impossible for water to collect inside the walls. 

Other repairs this year include repointing masonry, recaulking windows and doors, and replacing waterproof membranes on roofs. In addition, the kind of flashing Wright disliked is being installed in as many places as possible. “Yes, we are overruling Frank Lloyd Wright,” Jerome says. “But we are mostly using lead instead of copper because its gray color doesn’t stand out as much against Wright’s stonework.” Adds Jerome, “My goal is to enhance the exterior envelope’s performance, and that is a very difficult thing to do with Wright’s architecture because of its inherent design defects. So we design discreet interventions that make the exterior work better at shedding water and snow. And when we walk away, hopefully, no one notices our interventions.”

“It’s a huge undertaking,” Gunther says.

Still, the repairs aren’t as dramatic as those made around the turn of the century. Back then, engineers determined that several of the decks projecting out over the waterfall were drooping. The corner of one terrace was an incredible 7 inches below where it had been when the house was built. All reinforced concrete members bend a bit, the engineer Robert Silman explained at the time. There is an initial droop, often pronounced, on the day the concrete is poured, and a slower bending that occurs mainly in the building’s first year.

But some of the surfaces at Fallingwater never stopped bending, Silman said in 1999. The problem was that Wright had used less rebar—steel bars that strengthen concrete. To solve the problem 65 years later, engineers drilled holes through the concrete structure, then inserted steel cables through the holes. The cables were then tightened, essentially pulling the concrete up into position, a process known as post-tensioning.

Gunther says the post-tensioning, carried out under Fallingwater’s previous director, Lynda Waggoner, has performed well. But efforts back then to waterproof the house were less successful. “During the first restoration, we repointed the stonework and applied water repellent to the exterior, curing 59 of 60 chronic leaks in the main house and guesthouse,” says Jerome.

However, much of the water repellent was removed as the stone was cleaned over the last quarter century. As a result, many of the chronic leaks came back, says the engineer, who has been working on Fallingwater on and off since 1992.

Gunther was hoping to begin the waterproofing job in 2019, he says. “At the time, we thought it would cost around $3 million. Then the pandemic hit, and we had to put a lot of things on hold.” When the pandemic ended, “The bids jumped to about $6 million. Now we’re closer to $7 million.” Gunther was able to get about half the $6 million from the commonwealth of Pennsylvania. He raised the other half privately. But now, Gunther says, “We’re about $1 million short.” He is working to close that gap.

And it may not be the last time he has to raise money to keep Fallingwater dry. Jerome says she expects the liquid grout to last for at least 25 years. But water also gets in through cracks in concrete surfaces caused, in part, Jerome says, by Wright’s decision to include smooth river stones in the mix. Says Jerome, who in her 44-year career has devoted more time to Fallingwater than to any other project, “We’re doing the best we can. But it’s possible that there will always be some leaks.”

As for Fallingwater being scary: Jerome says she is 5’-4” but regularly examines buildings as tall as 50 stories from hanging scaffolds. So she says, “I don’t find the parapets at Fallingwater problematic.”