521 Antrim Road, Belfast, Co.Antrim, BT15 3BS

521 Antrim Road is a three-storey with attic mid-terrace house built in 1878 in the Georgian Revival style, possibly designed by Belfast-based engineer and architect Redfern Kelly (1845–1928), and constructed for local builder and contractor John Smith. It forms part of a terrace of nine houses on the east side of Antrim Road, between Glandore Gardens and Glandore Avenue, and is particularly closely related to five of these — formerly known as Castleton Terrace — which were developed simultaneously. The building bears a strong resemblance to the terrace at 416–428 Antrim Road directly opposite, which was built the following year and is attributed to Kelly, making his involvement here the most likely explanation. The listing covers the house and its yard walling.

The building is rectilinear on plan with a three-storey return to the rear. The roof is pitched natural slate with angled black clay ridge tiles, projecting eaves carried on block modillions, a painted moulded cornice and plain frieze, and half-round metal guttering discharging to circular downpipes. The red brick chimney stack is rectangular in section with a corbelled coping and clay chimney pots. A dormer window features projecting eaves, moulded timber bargeboards on corbels, and slated cheeks.

The two-bay principal elevation faces west. The ground floor is finished in smooth render, with the upper floors in red brick laid to English bond. Windows throughout are double-hung timber sash with 1/1 panes and ogee horns. The upper floor window openings have painted and moulded architraves, and the first floor windows have flat-headed moulded hoods. A painted moulded string course runs at second floor cill level. The entrance, set in the north bay at ground floor, is a square-headed door opening with an entablature supported on fluted columns with Ionic capitals, an elliptical fanlight above, and a panelled timber door opening onto three concrete steps. At ground floor level a three-sided canted bay window has square-headed openings, a raised parapet, and a moulded cornice. A uPVC hopper discharges to a circular downpipe. The north and south elevations are attached to the neighbouring properties at 523 and 519 Antrim Road respectively.

The rear elevation is red brick with a three-storey gabled return and a single-storey lean-to outhouse. A modern steel spiral stair provides a fire escape from first and second floor openings. Brick walls attached to the building have been painted white at ground floor level.

The setting to the front consists of banded block pavers forming a parking court, enclosed by plain painted metal railings, rendered low walling to the south, and a hedge along the north boundary, with a plain metal gate on metal standards. To the rear, the original red brick yard walls are topped by a projecting brick course and a canted red brick coping, returned both sides to form an enclosed yard. A set of steps at the east end of the yard, contained within a matching red brick wall, leads to a square-headed door opening set within a segmental relieving arch. This opening has a sheeted timber door giving onto an alley accessible from Glandore Gardens. The yard retains its original square terracotta paving flags and the original single-storey lean-to outhouse abutting the gabled rear return.

The Antrim Road was originally laid out in 1830, and by the 1850s the land to the north of the Belfast Waterworks and Limestone Road remained predominantly rural, as recorded on the second edition Ordnance Survey map of 1858. With Belfast's rapid population growth and the rise of the shipbuilding, rope-making and textile industries in the mid-19th century, the townland of Skegoneill quickly became one of the most affluent areas in the city, attracting gentlemen's mansions and wealthy merchant's houses. Numbers 519–527, together with the adjoining 517 and 529–533 Antrim Road, were built on the former grounds of Ashfield House, the home of solicitor Thomas McClelland. Ashfield House was demolished at the turn of the 20th century, though the majority of its grounds had already been built over during the 1870s and 1880s. The nine-house terrace, originally known as Castleton Terrace, was constructed in three phases, with the five Georgian-style houses at 519–527 being the first to be erected. All nine buildings appear on the third edition Ordnance Survey map of 1901–02, by which time the entire area had been developed with terraced streets.

Redfern Kelly was primarily an engineer who carried out major contracts for the Belfast Harbour Commissioners, including the deepening of the Victoria Channel, the reconstruction of the Alexandra Graving Dock following its collapse in 1905, and the construction of the Thompson Graving Dock, according to the Dictionary of Irish Architects.

No. 521 was initially valued at £36 and first occupied by B. McClean, a local wine merchant. By 1911 the property had passed to Mrs Mary Davison, whose house was described in that year's census as a first-class dwelling of thirteen rooms with a coal house as its sole outbuilding. Ownership of the terrace remained with the Smith family until the 1970s. Under the First General Revaluation of Property in Northern Ireland (1936–57) the house was occupied by Walter Kimmett, a manager in a local firm, and valued at £38. The house lay vacant during the Second World War. During the Second Revaluation (1956–72) it was occupied by a Mr J. A. Gallagher and revalued at £40.

The terrace was listed in 1987. No. 521 was converted from a private dwelling into offices in 1988. An extensive renovation in 1994 included the repointing of the red brick facade and chimney stack, reslating of the roof in natural slate, installation of the current dormer window, and restoration of the window frames. The building was subsequently in use as an orthodontic surgery. Despite conversion, much of the original historic fabric is retained internally and, aside from some modification to the ground floor, the layout remains unaltered. The building has group value with the other listed buildings in the terrace.