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Equitable Building

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Commonwealth Building
1944–1948, Pietro Belluschi. 421 SW 6th Ave.
  • (Photograph by Leland M. Roth)

One of the first glass-sheathed office buildings erected after World War II, the Equitable Building (also known as the Commonwealth Building) in Portland, Oregon, was designed by Pietro Belluschi and built in 1945–1948. Aside from having a smooth, virtually flush surface of large double-pane glass windows, this was also the first large-scale demonstration of the practicability using of a heat pump to provide both winter heating and summer air cooling. Though the Equitable was initially lauded in the architectural press, subsequent high-rise, glass-enclosed buildings, like as the Lever House in New York, soon overshadowed it. Though the building’s pioneering achievements were largely ignored for several decades, Belluschi’s Equitable Building is now recognized for its early use of a concrete building frame, for its external cladding in aluminum panels, for its expansive use of glass, and especially for its employment of a sustainable source of internal climate heating and cooling.

In the early spring of 1929, the Portland-based Equitable Savings and Loan Association (a division of the Commonwealth Trust and Title Company) commissioned the architectural firm of A. E. Doyle to design its new headquarters. Belluschi, by then the principal designer in the Doyle office, produced two different schemes before the deepening crisis of the Depression quashed the project. The first was a tall, staggered, setback Moderne-style tower whose 28 stories would have made it the tallest building in Portland; the second was two stories shorter and slightly more severe. As the onset of World War II further postponed the project, these initial schemes remained on the drawing boards. In the interim, Belluschi designed his clients a temporary, two-story building in a form that he later expanded and improved upon for the Federal Reserve Building in Portland (1948–1949).

In the Pacific Northwest, the recently completed the Bonneville Dam (1934–1938, Public Works Administration) generated hydroelectric power used in the production of aluminum, a material that was critical to the war effort. As early as 1943, J. Paul Raver, head of the Bonneville Dam Administration, investigated other uses of aluminum and even discussed with Belluschi its potential structural use. In early 1944, with the end of the war seeming imminent, Ralph Cake, the Equitable’s director, recommenced the long postponed headquarter project and entered into renewed design discussions with Belluschi. In the meantime, the editors of Architectural Forum had invited Belluschi to participate in their special issue, “New Buildings for 194X.” The project Belluschi published in May 1943 was a strikingly lean and efficient postwar office building. With sheer walls of metal and glass, it clearly prefigured the Equitable Building.

In January 1945, Belluschi prepared preliminary drawings for new Equitable Building and published the design in the Portland Oregonian. When aluminum structural framing of the building proved impractical, Bellischi considered using a steel frame, but the possibility of serious galvanic corrosion between a steel frame and the external aluminum skin prompted him to choose, instead, a reinforced concrete frame. This utilized a new, high strength concrete that allowed for slender columns, and thus provided the appearance of a steel frame. The broad windows filling the space between the concrete and aluminum-clad frame members were interrupted by spandrel panels above the floors that were required by the Portland building codes, but Belluschi used dark-green cast aluminum panels to make them visually recede. The windows were specially manufactured double-pane hermetically sealed units, 8 feet wide on the long side of the building, with deeply green-tinted glass to achieve a 40-percent solar heat gain reduction. The finished building was extensively glazed: there are 435 windows, each about 70 square feet. And because Cake had acquired half of an entire Portland city block, the Equitable stood as a strong urban presence, in dramatic contrast to the lush sculptural massing of the Classical Revival U.S. National Bank (1916–1925, A.E. Doyle) directly across street. The Equitable’s proportions, enhanced by Belluschi’s attention to the size and dimensions of the repeated windows, were appropriate to the building modest scale: initially, it was only 12 stories in height, thought two additional stories and a penthouse level were added in the 1950s.

In addition to an innovative internal lighting system of 8-foot-long cold cathode tubes mounted just under the office ceilings, Cake and Belluschi worked with mechanical engineer J. Donald Kroeker to choose an electrically powered reverse-cycle (heat pump) heating and cooling system, using deep well water as its energy sink—the first application of a large-scale heat pump system in an American commercial structure. While the architectural qualities of Belluschi’s innovative building design earned it a place on the National Register in 1976, the even more pioneering heat pump system earned it National Register Mechanical Engineering Landmark status four years later.

Aside from these innovations, the flat nature of the building skin, in which there are no projections greater that 7/8 of an inch, meant that there was no way of attaching harnesses for window washers. Belluschi therefore designed an integrated track system running around the top edge of the building from which a suspended platform allowed for external window washing, an innovative accommodation quickly adopted in later high-rise office buildings.

Published prominently in Architectural Forum just after its completion, the Equitable Building influenced many subsequent office structures in their mechanical aspects, but the distance from the urban centers of Chicago and New York, and particularly the isolation from the highly influential publishing world of New York, meant that the structure was soon eclipsed by Mies van der Rohe’s Lake Shore Drive apartments in Chicago (1948–1951) and Lever House (1950–1952) in New York, designed by Gordon Bunshaft and Natalie de Blois of Skidmore, Owings and Merrill.

Eventually, however, Belluschi’s innovative advancements were recognized, especially with the building’s historic designations. In 1982, the American Institute of Architects awarded the Equitable Building its prestigious 25 Year Award. The award jury, chaired by Frank Gehry, declared the building to be “an aesthetic, technical, and engineering masterpiece.” Today, the Belluschi’s Equitable Building is seen once more as the first postwar expression of the modern skyscraper.


Clausen, Meredith. “Belluschi and the Equitable Building in History.” Journal of the Society of Architectural Historians50 (June 1991): 109-129.

Writing Credits

Leland M. Roth
Leland M. Roth



  • 1944


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Leland M. Roth, "Equitable Building", [Portland, Oregon], SAH Archipedia, eds. Gabrielle Esperdy and Karen Kingsley, Charlottesville: UVaP, 2012—,

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