16, 18, 20 Castle Street, Edinburgh

16, 18, and 20 Castle Street in Edinburgh are a pair of classical houses built after 1792. They are symmetrical, three-storey buildings with a basement and attic, featuring seven bays and located on a corner site. The exterior is made of cleaned droved cream sandstone ashlar with polished dressings. The ground floor has V-jointed rustication, long and short quoins, and an eaves cornice. The former common stair door at the center has been blocked to create a window, while the flanking bays have panelled doors with modern rectangular fanlights. The roof features three flat-roofed dormers, with an off-centre bipartite window flanked by a pair of tripartite windows. The gable is made of coursed rubble and has windows at the center.

The rear elevation is four bays and four storeys high, constructed from dressed rubble, with a three-storey closet tower at the center. There is a single-storey and basement extension in Rose Street made from stugged ashlar with a cornice, which mostly serves as a bar and has a tripartite entrance.

The buildings have 12-pane timber sash and case windows, ashlar coped skews, rebuilt ashlar stacks, and grey slate roofing.

Inside, the common stair has been removed, and both flats are now incorporated into No 16. The hall features a modern glazed screen, and there is a curving cantilevered stone stair with alternate decorative cast-iron banisters, along with a lift. The former dining and drawing rooms have panelled dados and plain painted chimneypieces. The south flat includes an attic stair with similar banisters, while the north flat has had its stair removed, with a rear room featuring a tripartite window with fluted pilasters and a painted and carved chimneypiece also with fluted pilasters. No 20 has an enriched ceiling in the entrance hall, a glazed archway with a fanlight, a former dining room with a panelled dado and grey marble chimneypiece, a similar chimneypiece in the rear room, and a former drawing room with a panelled dado, grey marble chimneypiece, and scrolled foliate frieze. The rear room has a black fossil marble chimneypiece. The extension at the rear includes office cloakrooms and a bar in Rose Street.