The original building consisted of eight classrooms clad in yellow brick with a red tile hipped roof with gables over the entry projections. The building was two stories and symmetrical. The building was built as a part of the Public Works Administration and was constructed to relieve overcrowding in the Polytechnic neighborhood. The school was named after Samuel S. Dillow, a Polytechnic civic leader. Dillow was a grocery store operator and President of the First State Bank of Polytechnic. He was also a Polytechnic School Board Trustee, when Poly had its separate school system. Although the architect is not officially known, the building resembles the Oaklawn Elementary School, designed by Joseph R. Pelich and constructed around the same time. The original window openings have been partially infilled. In 1950, an auditorium/cafeteria was added on the west side of the building. It was designed by Easterwood and Easterwood. In 1953, a two story six classroom addition, also designed by Easterwood and Easterwood, was constructed on the east side of the building. In 1957, sixteen more classrooms on two floors, were added to the south of the 1953 addition, and a new auditorium was added on the south side of the old auditorium/cafeteria. These additions were also designed by Easterwood and Easterwood. In 1989, a free standing activity building was added to the southeast of the 1957 classroom addition. In 1990, a one story classroom addition was placed on the south side of the 1957 addition that ran in an east/west direction toward Dillow Street.