Frederick Reichert Rapp, the adopted son of George Rapp, was a stonemason as well as the Harmony Society's business manager. He designed a number of buildings in Harmony and in the Harmonists' later towns of New Harmony and Economy (
BE46). His house here, modeled after town houses in Philadelphia with its Flemish bond brickwork and fanlit doorway, is by far the most elaborate in the borough. The glazed brickwork is highlighted by a subtle geometric pattern of a cross on a hill on the southern gable end. The house is larger than the average Harmonist house, with an extra bay on the northern end, matched in size only by the Mueller house (1810; 233 Mercer Street), which acted as both a residence and doctor's office. Opposite Frederick Rapp's house is that of George Rapp (c. 1811; 528 Main Street), which has the standard three-bay Harmonist plan but lacks the decorative touches of Frederick's house.