Preservation History

Preserving Fallingwater has been ongoing almost since its completion. From daily maintenance and housekeeping tasks to larger efforts to protect the house, the care of Frank Lloyd Wright’s masterpiece is paramount to the Western Pennsylvania Conservancy as it continues the important practice of monitoring and preserving Fallingwater for future generations. Fallingwater is a composition of varied materials—stone, concrete, steel, glass, and wood—each imbued with qualities that celebrated what Wright termed “organic architecture.” Like organic elements in nature, these materials have shown signs of deterioration over the past eighty years, due in large part to their exposure to a range of climate conditions, especially humidity and sunlight that have impacted the collections and the severe freeze-thaw conditions of southwest Pennsylvania and water infiltration that affect the structural materials. The preservation of Fallingwater is ongoing, and one reason visitors are asked to refrain from touching objects and furnishings in the house.

Reinforced Concrete

Fallingwater provided Frank Lloyd Wright with an opportunity to utilize a modern material with great structural capabilities that could be extended into dramatic cantilevered terraces, stepped and curved to provide a canopy walkway, and smoothly shaped to provide interest to stairs, eaves, and ceilings. Yet, reinforced concrete also provides the most preservation challenges to the house, and as early as the 1950s portions of the reinforced concrete fabric of the house were being reconstructed. The composition of the concrete used at Fallingwater for the walls was a mixture of cement, sand, and rounded river gravel. Within the concrete, steel reinforcements, long rods of different diameters, were added, laid in a crossed formation or bent to provide additional strength.  The rounded tops of parapets were formed of a cement and sand blend, applied by hand after the wall had cured. This “cold joint,” where the two applications meet, has resulted in long irregular cracking that also served as an entrance point for water to seep between the concrete walls and its finish stucco coat.

The same mix of concrete was used for the house’s trellises, long expanses suspended over the drive or cantilevered over terraces. The east trellis, off of the living room, which collapsed in 1953, 1973, and 1982 due to falling tree limbs, was last rebuilt using post-tensioned thread bars under the direction of Taliesin Associated Architects. More recently, in 2012, a beam of the drive’s trellis was replaced due to structural failing, and a section retained for study, should it be necessary in the future.

The replacement of all roofing surfaces in 1987 and 1988 under the direction of LD Astorino and Associates necessitated the recasting of several curved ends and corners of the concrete eaves. In 1990 a comprehensive analysis of the concrete and stone masonry was conducted by Wank Adams Slavin Associates in 1990. That same firm submitted a two-volume preservation master plan for Fallingwater in 1999 which included recommendations for the care and treatment of concrete as well as the other building materials used in the house.

The most invasive preservation action occurred during the years 2001 and 2002 when a structural strengthening of the living room cantilevers was conducted. From the time of their moving in to 1955, the Kaufmanns documented the deflection, or downward tilting, of the terraces to be approximately four inches. In 1994, a University of Virginia graduate student’s thesis research concluded that the terraces had deflected further, one to almost seven inches from its original position. This sparked a fuller investigation of the cantilevers by Robert A. Silman Associates, and crack meters and tilt meters were applied a year later to the terraces to record any changes. Their resulting five-volume structural analysis report informed much of the restoration that occurred from 1998 to 2002.

The analysis suggested that the concrete and steel of the terraces was overstressed due to errors in the design of their reinforcement, which meant they could no longer function as designed. The first step taken in halting the deflection was to install shoring and a steel support beam beneath the living room terraces. This was followed by the removal of the flagstone floor from the living room and the subfloor materials in order to expose the concrete beams beneath. A post-tensioning cable system was employed, where bundles of high strength steel cable were first anchored into the concrete piers beneath the house and then attached to the sides of three of the four the major reinforced concrete beams located in the living room and tightened.  This provided a support system that stopped the terraces from deflecting further and was all but invisible once the floor was replaced.

In 2011 cracks appeared in the reinforced concrete piers under the house, and so in 2013 a series of crack and tilt meters was installed to gauge the deflection, if any, of the terraces. Twelve crack meters monitored the master bedroom terrace and the concrete piers underneath the house, while four tilt meters affixed to the east terrace and west terrace of the living room and the master bedroom terrace monitored any vertical changes. A decade after the post-tensioning system was mounted, the terraces have only shown movement to approximately 1/100th of an inch. Fallingwater is continued to be monitored on a semi-annual basis.

Stone Masonry

Stone is perhaps the most symbolic of the materials used at Fallingwater. Pottsville sandstone was acquired from a nearby quarry to use in building walls, and laid in a rough, shifting manner to imitate the natural stone ledges found jutting out along Bear Run. Projecting beyond the line of the mortar as much as three or four inches, this technique was meant to help unify the house to its site, and the effect is one of making it appear that Fallingwater is growing out of its landscape. A recently acquired series of fifty photographs taken in 1936 and 1937 show the assembly of stone and the manpower needed to erect the walls, and help in understanding the way in which the house rose.

From a preservation standpoint, the arrangement of the stone and the deep crevices between each present opportunities for water to pool or seep into the walls, leading to damage on interior ceiling and wall surfaces. The ledges of each row of stone have small depressions within which water accumulates, and permits for the accumulation of snow that, once melted, is drawn into the joints of the walls. The mortar, too, can be responsible as any gaps between it and the stone will lead to hairline cracks and separations that with seasonal freezing and thawing often become more problematic over time.

For horizontal surfaces, flagstone was used throughout to provide seamless transitions between the exterior and interior. These relatively thin stones, averaging around two inches in thickness, were hand laid and assembled freeform across the floors, terraces, and stairs of the house. They fit snugly against the boulder of the living room hearth, and when used on the interior are waxed to appear wet like the stream bottom of Bear Run. When the living room floor was removed in 2001 to install the post-tension cable system, 557 stones were individually numbered, stored safely, and later reassembled like a giant jigsaw puzzle.

A thorough cleaning of the exterior stone walls is performed periodically, the most expansive undertaken between 1989 and 1992 under the direction of Wank Adams Slavin Associates. In 2012, two sides of the chimney mass were cleaned to remove salt build-up, staining, and biological growth. Removal of moss on the capstones running along the tops of the roof parapet, a key indicator of water infiltration, is part of routine preservation maintenance and various areas of the house are repointed as needed as part of the ongoing care of the masonry.


Glass is an important element of Fallingwater’s design, acting as a protective barrier between indoors and outdoors, but also as a framework to the nature beyond. Frank Lloyd Wright specified quarter-inch thick polished Pittsburgh Plate Glass for the house and it was used in all windows, the full-height doors leading to the terraces, and in horizontal applications such as skylights and the telescoping hatch doors leading to the stream below the living room.

It also plays a role in illustrating the engineering properties of the house’s cantilevered design where glass meets glass to create an “invisible” corner window. Wright uses this technique to show there is no need for the traditional vertical supports at the corners of his rooms, and the absence of a corner mullion provides an uninterrupted, if not dramatic, view to the outdoors. From the exterior, especially when the house is lit at night, the glass seems to disappear entirely and enhancing the effect of Fallingwater as a “lantern in the forest.”

In 1987, the original window glass was replaced with a laminated ultraviolet light filtering glass that helps to protect the interiors, furnishings, and artwork from harmful sunlight. In 2010, many windows began to show signs of delamination, or cloudiness, especially evident around their frames, a main indicator of the glass’s failure. Fallingwater’s Window Legacy Fund was established soon after to create an endowment that provides for continued care and replacement of the window and door glass, and consequently its collections.


The use of steel at Fallingwater is both invisible and everywhere apparent. Reinforcing bars used within the concrete provide tensile strength , and are inserted in varying ways into the liquid material as it is formed. In walls and floors, it is arranged as a woven mesh while in the covered canopy of the stairs to the guest house, it is laid as a series of concentric arcs. Repairing concrete will also often mean exposing or working around embedded reinforcing bars, in some cases cutting through them, which can add difficulty to a preservation project. If exposed, the bars are coated with a noncorrosive agent to keep them from rusting within the new concrete.

The windows and door frames at Fallingwater are also made of steel, and were specified by Frank Lloyd Wright to be manufactured by Hope’s Windows of Jamestown, New York. At a time when sashes were traditionally made of wood, the steel was a relatively new material for Wright, who in the January 1938 issue of Architectural Forum wrote, “Steel sash came within reach…for the first time.” The manufacturing process, rolling steel into Z or T shapes to ease fabrication, allowed for a variety of special shapes. Originally painted “Cherokee” red, the name for a variety of earthy red hues preferred by Wright over his career, the color deepened with subsequent near-matches by other manufacturers, but returned to Wright’s specification by Edgar Kaufmann, jr. in 1976.

In 2000, the original but somewhat deteriorating steel sash windows and doors were restored, with many layers of paint removed, corroded portions replaced, and the painted finish reapplied. In 2012, a second large-scale restoration of the steel sash was conducted on a selection of windows and doors throughout the house, and this preservation continues to be part of Fallingwater’s annual maintenance plan.

Specialty Finishes

The use of cork tiles on the floors and walls in Fallingwater’s six bathrooms was at Edgar Kaufmann jr.’s suggestion, feeling that Frank Lloyd Wright’s specified stone floors would be too cold when leaving the shower. The natural color of cork, a tree bark product, related well to the palette of materials Wright specified overall, and had the added acoustic benefit, warmth, and softness underfoot. When used as a flooring material, the cork tiles were hand waxed, giving them a shiny finish that supplemented their natural ability to repel water.

As a wallcovering, the cork was left unwaxed, its natural state and color provided visual interest though it  began to show water damage in locations were water leaks persist. . The effects of water damage on the cork is still evident in the guest bathroom of the main house, yet the bath in the guest house was restored in 2007 with the concrete wall surface renewed and  repainted before new cork was applied. The variety of bathroom configurations in the house was such that cork covered part or all of the walls and was sometimes used as flooring within the shower stall.

The largest room without flagstone flooring is the kitchen, where a nine-by-nine inch asbestos tiling product was specified for ease of maintenance and comfort for the Kaufmanns’ cook. In 1988, after nearly fifty years of wear, the kitchen flooring was replaced with a solid vinyl product, cut to size and custom colored to match the “Cherokee” red of the original. A second replacement, in 2013, gave the floor a fresher appearance and closely resembles the original in size and color.


Fallingwater’s stucco-covered concrete has always been painted, its original light ochre color specified by Frank Lloyd Wright in 1937. Despite the architect’s proclamation in the January 1938 issue of Architectural Forum that the rounded roof edges would keep the concrete walls clean by allowing water to roll off, the paint finish soiled often. Organic debris from overhanging trees, collecting and degrading on the concrete surfaces, also produced prime conditions for encouraging fungi along the roof joints.

Peeling paint was also becoming an issue as the house aged, with so many layers applied that the walls appeared as if the stucco had loosened. Between 1937 and 1959, the house had been repainted at least six times, using a variety of paint manufacturer products, and in 1978 the house was sandblasted to remove all of the paint before the concrete was waterproofed and covered with an acrylic-based paint coating.

The exterior paint continued to fail, particularly on the building’s vertical surfaces. Between 2001 and 2006, Fallingwater evaluated over 120 exterior paint test panels produced by four different manufacturers in applications on and near the guest house before selecting specially colored ochre tinted exterior flat paint product developed by PPG Paints. Like any house, the interior and exterior concrete surfaces of Fallingwater are repainted periodically.

Furniture Conservation

The nearly 170 built-in and freestanding wood furnishings designed by Frank Lloyd Wright for Fallingwater share many of the characteristics of the house itself. Fabricated of North Carolina black walnut, the tables, shelving, desks, and banquette seats feature cantilevered horizontal elements, their edges and corners rounded to soften the line and suggest the rounds edges of the concrete parapets. Door fronts and table top veneers contain a light colored band of sapwood within the grain field to give them movement and variety.

In 1986, conservation of Fallingwater’s wood furnishings was undertaken with funds provided by the Getty Grant Program and the National Endowment for the Arts, with later support from the Pennsylvania Council on the Arts. The work entailed cleaning woodwork, making small repairs, and addressing structural concerns where water damage or deterioration had occurred. During this time, a large section of the second floor hall cabinets was removed and replicated. The damaged piece, stored away for reference use by the conservation team, still provides insight into the construction methods used to realize Wright’s designs.

The uneven quality of previous restoration treatments was corrected and since the completion of that intensive conservation effort, general woodwork cleaning and repairs to a selection of furniture has been part of Fallingwater’s annual winter maintenance program. A standardized series of conservation treatments was established by conservators Thom Gentle and Victoria Jefferies, in many cases improving upon restoration methods used in the past, and continues under the direction of Sean Fisher of Robert Mussey Associates. Year-round, Fallingwater’s housekeeping team maintains the general condition of the wood furniture, with light dusting the only method used to maintain its finish.

The upholstered zabuton floor cushions, banquette seat cushions, and lounge chairs also require occasional updating. The fabrics are vacuumed regularly, and when reupholstery is necessary, fabric is used from stock saved in our collections storage for just that purpose. In the spring of 2014, the two off-white T.H. Robsjohn-Gibbings lounge chairs were recovered in a replacement fabric of the same shade, but not the same texture, of the original. Seat cushions for the dining table and desk were also recovered at that time, using the red-orange colorway of the same wool fabric.