NATURE CANTILEVERED those boulders out over the fall,” said Frank Lloyd Wright about the site of his most famous house, Fallingwater. “I can cantilever the house over the boulders.” As it turned out, however, Wright did not entirely meet the challenge set by nature. From the very beginning, Fallingwater has been falling down. At the 2002 annual conference of the Frank Lloyd Wright Building Conservancy, held in September in White Plains, New York, speakers addressed the twin issues of water damage and structural deficiency that threaten the building.

Wright was far ahead of his time in his use of materials and methods—so far, in fact, that the demands he placed on the new technology of monolithic concrete construction exceeded the capabilities of building techniques at that point. As a result, water has had more than 60 years to seep into the structure. “The environment is extremely damp,” said Norman Weiss, a consultant for Wank Adams Slavin Associates, the firm engaged to design the waterproofing of the structure. “Let’s just call it wet.” Tiny cracks in the concrete and inadequate flashing—the use of metal to protect vulnerable connections—have allowed water to permeate the walls and parapets. Wright’s ultraclean design stymied a waterproof membrane installed on the roofs in the 1980s; there was simply nowhere to fasten the edges down. The dampness inside and outside the building forced the valiant maintenance staff at the Western Pennsylvania Conservancy, which runs Fallingwater, to repaint the entire exterior every other year. It could have been worse: Wright originally ordered the buildins covered in sold leaf.

An even more dangerous problem has plagued the building from the outset. Fallingwater lore claims that on the day the wooden construction scaffolding was removed from the second-story terrace, a crack appeared. Those present called the building’s engineer, who is supposed to have exclaimed, “My god, I forgot the negative reinforcement!” By then it was too late to insert the stabilizing metal bars that are usually set along the top of a concrete span, and Fallingwater has done without ever since. Structural analysis begun by a student at the University of Virginia and carried on by the engineering firm Robert Silman Associates indicates that the building was dangerously unstable, even though its contractor secretly used far more reinforcement than Wright called for. Over the life of the building, cracks have continued to develop and widen. The terraces at the east and west ends of the living room droop visibly.

Determined to save Fallingwater, the Western Pennsylvania Conservancy has been aggressively refurbishing the house for almost a decade. The first step was to brace it with support scaffolding anchored to the stream bed below. Since the stream is a protected area, the rock cores removed to grout the anchors in place had to be saved. They’ll be glued back in place when construction is complete, probably in the next few months.

To stop the slow collapse of Fallingwater’s cantilevered terraces, the engineers devised a surprisingly simple arrangement. First, they removed the flooring from the main level of the house, a task that required Wank Adams Slavin Associates to number and document each flagstone. Then engineers fastened a steel cable to the underside of one end of each structural floor support, strung the cable across a concrete anchor point positioned atop each support over the edge of the cliff, and attached the cable to the other end of the support. Using jacks to tighten the cables, engineers pulled up the drooping ends, essentially hanging the floor from itself like a suspension bridge.

A new waterproofing plan promises to make the building leakproof for the first time ever. In addition to applying membranes of rubberized asphalt and polyethylene to the concrete, restorers have recently installed an improved system of flashing and drains. Paint technology has finally caught up with Wright’s ideas, and high-tech paints are being tested for application over the newly repaired parapets on each of the terraces. It’s not gold leaf, but it just might secure the rest of Wright’s vision.