12 Carlton Terrace, Edinburgh

12 Carlton Terrace is a substantial, early 19th-century townhouse forming part of a long, sweeping terrace in Edinburgh, designed by William Playfair between 1821 and 1825 and built from the late 1820s to the mid-1830s. It is one of a group of nineteen classical townhouses, notable for their varying plans; numbers 1-4 and 14-19 are rectangular, while numbers 5-13, including number 12, have wedge-shaped frontages. The building is two storeys high with a basement and features a balustraded parapet, with panelled sections to numbers 1, 14 and 17.

The exterior is constructed with droved ashlar to the basement, polished ashlar to the upper floors, and coursed squared rubble with droved margins to the side and rear elevations. A base course, dividing bands between the basement and ground floors and the ground and first floors, and a modillioned eaves cornice feature on the front elevation, while a simpler eaves band is present at the rear. Raised door surrounds are accentuated by consoled cornices. The fenestration is regular, with architraved and corniced windows, including panelled aprons to the ground floor and cast-iron balconnettes to the first floor.

The principal (northeast) elevation has a timber-panelled basement door with a blocked fanlight, and largely obscured windows in the remaining bays. A mono-pitch roofed ashlar extension with two windows partially obscures one window. Steps and a platt lead to a timber door with a rectangular fanlight on the ground floor of the second bay from the left. Behind the balustrade, a corniced mansard roof is punctuated by two bipartite dormer windows.

A full-height, piend-roofed square-plan extension, a later addition, is visible on the rear (southwest) elevation.

The windows are predominantly timber sash and case with 12-pane glazing, although plate glass is used on the first floor to the front, while the central bay to the rear has 8-pane glazing and the dormers feature 4-pane glazing, with 9-pane glazing in the basement extension. The roof incorporates a flat profile with a mansard to the front and a pitched roof to the rear, covered in graded grey slate, with stone skews and skewputts. Mutual ashlar stacks are present at the front, preceded by two octagonal flues, while rendered stacks are found at the rear. Generally circular cans top the corniced stacks. Some cast-iron rainwater goods are also present.

Stone coping with cast-iron railings, dog bars, spear-head finials, and a distinctive circled border defines the front basement recess and platt, with a wrought iron lamp standard located to the right. Random rubble boundary walls with flat coping enclose the rear garden.

The interior ground floor features an encaustic tiled floor in the lobby, a corniced and pilastered doorpiece, compartmented ceiling, and good plasterwork. The former dining room contains a classical black marble fireplace with a corniced and pilastered doorpiece and further decorative plasterwork, including a ceiling rose. A painted stone classical fireplace and further good plasterwork are found in the room to the east. Simple cornicing is prevalent throughout the remainder of the ground floor.