After fire destroyed the previous school building in December 1932, reinforced concrete was the material of choice for the new school building. With one eye on the U.S. Post Office and Court House, then under construction, city leaders used the same material, derived cost estimates from the federal building experience, and even drew on the design.
Main School has a two-story central block flanked by two-story hyphens and wings. Each window bay, divided by concrete piers that rise above the roofline in a contrasting dark color, has large windows separated by concrete spandrels with bas-relief panels. Vertical gouges above the windows are repeated on the piers. The blank front walls of the wings have slightly recessed and raised panels; the sides have the same fenestration and ornament as the front of the building. On the interior, classrooms are arranged in a U-plan on the perimeter, with the auditorium in the center of the building expressed by a rounded element on the rear. In 1939, a large addition to the rear of the south wing was constructed with Public Works Administration funds. In 1948 a similar addition was made to the north wing.
Joseph D. Boyer, the engineer supervising construction of the U.S. Post Office and Court House, devised schematic plans for this building that were then fully drawn by a Portland, Oregon, architectural firm. It is not known who contributed what to the design, but its resemblance to that of the federal building indicates that Boyer's influence was strong. The William MacDonald Construction Company, which also had the federal building, contract, was hired to construct the building for $117,000 in May 1933. The building was occupied in January 1934 and was used as a school until 1976. It now houses school district offices.