The Faults of Fallingwater

Mistakes have plagued Fallingwater, yet the extraordinary beauty of the house and the delight it brought to the life of its inhabitants form the context in which its construction should be evaluated. Life at Fallingwater did include flaws and the efforts to overcome them. Before the family moved in, there were doubts about the structure....

...and when cracks appeared in the east and west parapets of the terrace of the main bedroom it was necessary for Wright to reassure his client that the building was settling, not fracturing. Did they discuss what seems obvious today, fifty years later? Overloading the beams of the main floor with extra heavy reinforcing rods caused the slab to sag more than should have been expected, and since the two floors were tied together - especially by T irons in the window framing of the south front - the upper terrace was bound to follow. Moreover, this upper floor, extending six feet farther than the living room, had been stacked with heavy bags of cement during construction despite objections from Wright's representative. There is no proof that this extra load augmented the damage, yet it was foolhardy. Further cracks developed but the first two were the worst; they kept worrying my father throughout his life. They may have been a burden to the architect as well, if a report is accurate that shortly after construction Wright, in a high fever from pneumonia, was heard to mutter "too heavy." Evidently he was envisaging Fallingwater. Those two cracks require cosmetic patching even today, but there is no evidence of structural failure.

Structural failure is mistakenly deduced from the way horizontal edges of the house dip downward. This is due to an oversight in setting up wood forms into which the concrete was poured; they were built level, not sloped upward to allow for settlement when the forms were removed. It is hard to understand how this came about. Wright had considerable familiarity with reinforced concrete, and he was assisted by experienced structural engineers. My father had his own advisers, engineers, and job supervisor. None of these men warned the contractor, who proceeded in sheer ignorance. Considering the various facts it is not surprising that the contractor was frightened to strike out the supports of the forms when the time came. But at Wright's command the posts were struck, and no disaster followed. Much later two subordinate overhangs did fail: the roof over the eastern terrace because of incorrectly placed reinforcing rods, and the trellis over the southerly corner of the living room because a heavy tree branch fell on it during a storm. Both have been satisfactorily rebuilt.

Why do those two major parapet cracks reappear? The answer leads to wider issues. Over the years my father had his engineers reporting on deflections of the concrete; after a while it became obvious that the cantilevers fell and rose in response to temperature changes affecting the materials. Deflection was small in either direction, but the constant movement reopened cracks and strained flashing between roofs and walls, a delicate joint in any building. When the flashing opened up, even inconspicuously, water penetrated, then threaded through interstices, and issued far from the point of entry as distressing leaks. There were seventeen such areas when we first moved in. Roofing and terrace flooring where lifted, stray chunks of sodden lumber were extracted, and shopping sheets of insulation were replaced with dry ones; the house became presentable inside. Had the insulation been wet before it was sealed in? Not unlikely, but damaged flashing was more surely responsible. Some leakage still occurs, and now a concerted effort is under way to rework all flashing. To do this and yet maintain the neatness of the exterior will be a challenge.

Besides these troubles there has always been a question about the parapets: do they strengthen the great horizontal concrete slabs or merely weigh on them? Wright himself after much deliberation believed they helped to carry the load, but not so effectively as he had hoped....

...The small deflections (up and down) at Fallingwater were not foreseen; neither were those (from side to side) in early skyscrapers, yet these are now accepted as normal. Some of the great monuments of architecture have suffered structural troubles, precisely because they were striving beyond normal limitations....

- Edgar Kaufmann, Jr., Fallingwater: A Frank Lloyd Wright Country House, pp. 49-51.

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