15 Clarendon St, Londonderry

15 Clarendon Street is a mid-Victorian mid-terrace townhouse built around 1861. It is a two-bay three-storey building with an attic, rendered throughout, and rectangular on plan with a projecting rear return. Numbers 11, 13 and 15 Clarendon Street are treated as a single architectural composition within a terrace of predominantly brick-faced townhouses in the Clarendon Street Conservation Area.

The principal elevation faces north, set behind a low painted rendered boundary wall surmounted by replacement metal railings, with a small hard-surfaced forecourt. The pitched slate roof is finished with black clay ridge tiles to the main roof. A large rendered chimney stack with nine terracotta pots rises from the east, centred on the ridge. Cast-iron guttering runs to the front elevation.

The principal north elevation is painted render with deeply ruled ground floor and smooth upper floors, with quoins to the right. The entrance doorway features a three-centred arch opening with a recessed cornice supported by scrolled console brackets on pilasters either side, containing a painted timber four-panelled door with a plain fanlight above. To the left of the door is a single tripartite timber sliding sash window (1/1, 1/1, 1/1 panes) surmounted by a hood mould supported by scrolled console brackets. Two windows occupy the first and second floors, though not aligned with the ground floor openings. First floor windows have a continuous sill course and moulded surrounds. All windows are square-headed 1/1 timber sliding sash unless otherwise noted. The east and west elevations are abutted by adjoining buildings (Nos. 13 and 17 Clarendon Street).

The south (rear) elevation is smooth cement rendered across three storeys with an attic. A smooth-rendered three-storey pitched roof return extends to the left at half-landing height, abutted by a single-storey hipped roof rendered extension. The right bay features a single 1/1 timber sliding sash window with coloured leaded glass behind a metal security grill at ground level, surmounted by a single 6/6 timber sliding sash window to the first and second floors, and a 2/2 timber sliding sash window in a pitched roof dormer. The exposed section of the left bay has a single 6/3 timber sliding sash window. The three-storey rear return's south face is abutted by a single-storey return; the exposed section has a single segmental-arched 2/2 timber sliding sash window with coloured glass margin panes to the first floor, surmounted by a 6/6 timber sliding sash window. The east face has diminutive window openings to the first and second floors; the ground floor was not visible at the time of survey. The west face was not visible at survey. The single-storey return comprises a blank south gable, while its east face has a door opening to the left, a window opening to the far left, and two window openings to the right. The west face was not visible at survey.

To the rear of the site is a two-storey mews building, now roofless with its window and door openings blocked up. A small single-storey lean-to building with a corrugated metal roof abuts the right side of the north face of the mews building. An enclosed yard lies to the rear of the main house.

Materials comprise natural slate roofing, cast-iron rainwater goods to the north elevation (uPVC to south), rendered walling, and timber windows.