Largely unchanged, the structure was designed in the Gothic Revival style by an unknown architect, with masonry-bearing walls with timber framing at the roof and floors, and brownstone foundation walls and exterior door and window trim. The front facade (west, on Norfolk Street) is "stuccoed and scored to simulate smooth-faced ashlar", though the other elevations are faced in brick. Window tracery was all in wood. Much of the original work remains on the side elevations. Characteristically Gothic exterior features include "vertical proportions, pointed arched window openings with drip moldings, three bay facade with towers". Gothic interior features include "ribbed vaulting" and a "tall and lofty rectangular nave and apse." Originally the window over the main door was a circular rose window, and the two front towers had crenellations in tracery, instead of the present plain tops. The square windows below are original, but the former quatrefoil wooden tracery is gone in many cases. The bandcourse of quatrefoil originally extended across the center section of the facade.