Three tall stories of brick over a raised basement, in the elaborated manner of the 1880s. The front breaks forward at the center into an entrance pavilion carried up as a tower, its steep roof rising to a finialed peak above a bracketed and paneled stage. Windows are tall and narrow with segmental heads, grouped in the pavilion and paired along the wings, and heavy corbelled brickwork marks the cornice. A lower, plainer brick building — the 1858 school — stands immediately to the west behind the same picket fence.
Blow School's second building was raised in 1883 on the same Carondelet block as the 1858 school, which continued to stand beside it. The St. Louis Board of Public Schools built it under its stated policy of enlarging crowded schools by putting up additional buildings on sites already in use rather than opening new ones; by rule its plans would have come from the Board Architect, H. William Kirchner, who held that office in 1881 and 1882. A photograph of the two buildings together, later copied by the Missouri History Museum, is captioned "2nd Blow School 1883." Both the 1858 and 1883 buildings were cleared around 1903, when William B. Ittner's Blow School replaced them on the site.
