12a Charterhouse Square, and Walls and Railings

No. 12A Charterhouse Square is a terraced house built in the late 18th century, with a bowed window added to Charterhouse Square in the mid-to-late 19th century. The building is constructed of yellow brick in Flemish bond, with stone details and a slate roof. It has four storeys above a basement, featuring one window facing Charterhouse Square and four windows facing Rutland Place.

Access to the house is via steps leading up to a round-arched entrance on Rutland Place, which is adorned with fluted quarter-columns, a cornice, and a fanlight with decorative glazing. The windows on Rutland Place are flat-arched with gauged brick heads, though several are blank. On the Charterhouse Square side, there is a segmental-bowed window at the basement, ground, and first floors, featuring triple windows with stone mullions and lintels, and curved 9/9 sashes. The building also has a dentil cornice and a blocking course with iron railings on the balcony. The second-floor windows are flat-arched, and there is a frieze of brick designed to resemble triglyphs, along with a parapet and dormers in the mansard roof, with chimney stacks on the north side and on the party wall to the west.

To the north of the house, there is a late 18th-century brick screen wall that includes two flat-arched entrances with pilasters, cornices, and fanlights, as well as two blank flat-arched windows. This wall also features a brick frieze that mimics triglyphs and a parapet. The screen wall in Rutland Place has a flat-arched entrance with pilasters, a cornice, and an overlight, along with two blank windows and a similar brick frieze. The property is complemented by cast-iron railings on the steps in Rutland Place, which have iron-twist balusters, and area railings in Charterhouse Square with spearhead finials.