21 Fountain Street, Londonderry, Co. Londonderry, BT48 6QX

21 Fountain Street is a modest mid-terraced two-storey, two-bay Victorian townhouse built in 1883, forming part of a uniform stepped terrace of fourteen similar houses lining the north-west side of Fountain Street, just outside the historic city walls of Londonderry. The terrace sits between New Gate and Ferry Quay Gate, backing onto the city walls, and lies to the east of St Columb's Cathedral. The building is rectangular on plan with a projecting two-storey rear return with a pitched roof.

The principal south-east elevation faces onto Fountain Street, overlooking former industrial buildings on the opposite side of the street, and is set at the back of the pavement. It is built in English Garden Wall brick bond using red brick with contrasting Victorian polychromatic brick dressings — a style the Conservation Area Design Guide describes as reflecting "the Victorian taste for polychrome brickwork derived from the Venetian Gothic." The eaves feature an ornamental projecting brick cornice with a double band of black brick dressings below. Continuous decorative stringcourses in contrasting black brick run at sill and head level on both ground and first floors, with a further row of black brick separated by three courses of red above sill level and below head level.

There is one segmental arch-headed window opening on the ground floor and two on the first floor, along with a segmental arch-headed entrance door opening set one step up from the pavement. The front door is a six-panel hardwood design with a plain segmental-headed fanlight above. All openings have red brick voussoirs to their heads, with three black bricks at the centre forming a keystone detail. Ground and first floor windows are one-over-one timber sliding sash with exposed sash boxes. All sills have a painted finish over stone.

The roof is natural slate with a pitched form, a pair of small rooflights to both the front and rear slopes, and black ridge tiles. A large red brick chimney stack rises from the north-east side, centred on the ridge, with only two clay pots remaining. It has double bands of black brick below a projecting decorative brick course. Rainwater goods are uPVC to the front and cast iron on drive-through brackets to the rear.

The north-west rear elevation is of painted rendered finish. The two-storey pitched-roof return to the right is also of painted render with a slate roof and a single central window at first floor level to the rear. A single-storey monopitch extension sits behind, containing coal houses. The exposed section of the rear elevation has a single timber sliding sash window at both ground and first floor levels, with paired sliding sash windows to the kitchen return facing the yard. The north-east and south-west sides abut the adjoining properties at numbers 19 and 23 Fountain Street respectively.

The south-east boundary of the setting is formed by the historic city walls.

Fountain Street has a long history of development outside the walled city, with houses recorded on the site as early as 1685 on contemporary maps — making it one of the earliest streets to be developed beyond the walls. According to historian D. Calley, the street was originally built up only on the side away from the walls, which was kept clear for defensive purposes. It had acquired the name Fountain Street by the 1830s, in reference to a fountain located next to Church Bastion.

The 1848–49 Ordnance Survey Town Plan and the circa 1873–1910 Annual Revisions map show that Fountain Street originally extended from Ferryquay Street around the city walls before terminating on Bishop Street. Before the current terrace was built, the site between Ferryquay Street and Hawkin Street was occupied by a number of irregular-sized buildings leased by Hamilton Graham, a local bookkeeper who resided on the Northland Road. This earlier row was demolished and replaced with the present uniform terrace in 1883. The terrace continued to be leased by Hamilton Graham (who died in 1892) and was occupied by working-class labourers, the majority employed in the neighbouring factories and local industries — many of them undoubtedly working at the Welch Margetson Shirt Factory on the opposite side of the street.

The terrace first appeared in plan form on the circa 1873–1910 Annual Revisions Town Plan for Londonderry. Following completion, Number 11 Fountain Street was valued at £8, and the first recorded occupant was James McGonigle, a bank messenger whose wife and daughter were machinists in a local factory. The 1901 census described Number 11 as a second-class dwelling of six rooms with a coal house as its sole outbuilding. Under the First General Revaluation of Property in Northern Ireland (1936–57), the value rose to £12; the valuer noted the building was occupied by a Mr Robert Greer in the 1930s and was purchased by the Convent of the Sisters of Mercy on Pump Street in 1945. Under the Second Revaluation (1956–72), the property was occupied by a Mr A. Shields and its value had risen further to £15 and 10 shillings.

In the 1970s, the stretch of Fountain Street extending from Hawkin Street to Bishop Street was demolished and the area redeveloped as a modern housing estate. Calley notes that this demolition also obliterated Albert Street and Place, Fountain Place, Victoria Street, Clarence Place, one side of Kennedy Street, and all but a single tower of the City Gaol. Numbers 11–35 Fountain Street are among only a small number of terraces to have survived this redevelopment, and they represent a remnant of the once strong industrial working-class character of the Fountain area, which provided workers for Londonderry's local shirt-making and shipbuilding industries during the city's prosperous late Victorian period.

The terrace was included in the Historic City Conservation Area in 2006. Number 21 itself has group value as part of Nos 9–35 Fountain Street but has insufficient original fabric remaining to meet the criteria for individual listing.