12 Regent Terrace, Edinburgh

12 Regent Terrace is a significant example of early 19th-century Edinburgh architecture, designed by William Playfair and constructed between 1826 and 1833. It forms part of a long terrace of 34 classical townhouses, originally designed with two storeys, an attic, and a basement. Many of these houses have since been extended with an additional third storey. The terrace is punctuated by two larger, three-storey pavilions with advanced three-bay sections at each end (numbering 11-16 and 23-28), and a twelve-bay, three-storey section at the western end (numbers 1-4). The terrace steps down at intervals to follow the natural slope of Regent Terrace.

The building is constructed of droved ashlar on the basement level, polished ashlar on the upper floors, and predominantly coursed squared rubble with dressed margins to the rear elevation. Key features on the principal (southeast) elevation include a base course, dividing bands between the basement and ground floor, and ground and first floors, and an eaves cornice. A continuous cast-iron trellis balcony with a Greek key border runs along the first floor. The doorpiece is painted and features fluted, attached Greek Doric columns. The fenestration is regular, with architraved windows on the ground and first floors, and panelled aprons to the ground-floor windows. The rear elevation has predominantly regular window placement.

The basement level of the principal elevation features a blocked fanlight above a timber panelled door, a window to the left, and an area blocked by a wall with two windows to the right. The ground floor has steps leading to a two-leaf timber and glazed door with a letterbox fanlight.

The rear (northwest) elevation is three bays wide, with a full-height, piend-roofed, rendered section in the centre bay and a large, single-storey extension attached to it.

Most windows have plate glass, with 12-pane glazing on the first floor and 12-lying-pane glazing on the second floor of the rear elevation. Windows are predominantly timber sash and case. The roof is an M-shape with a central valley, covered in graded grey slate with stone skewbacks and skewputts. Corniced mutual ridge stacks extend from the east and west sides, with octagonal flues visible on the front, and a wallhead stack serves the rear extension. The stack terminals are predominantly circular cans.

Original cast-iron railings with dog bars, spear-head finials, and a distinctive circled border run along the front, defining the basement recess and platt. A wrought iron lamp standard is situated to the left of the platt. The rear boundary is formed by random rubble walls with flat coping.

The interior of the ground floor includes a lobby with a geometric tiled floor, compartmented ceiling, ornate plasterwork, a screen of pilasters and fluted Ionic columns, and a stone cantilevered staircase with ornate cast-iron balusters.