Mountpottinger Presbyterian Church, Castlereagh Street, Belfast, County Antrim

Mountpottinger Presbyterian Church is a double-height Romanesque-style Victorian Presbyterian church located on Castlereagh Street in east Belfast, built circa 1868 to designs by William Hastings. The building comprises a rectangular plan form with curved stairwells added circa 1885, reputedly by W.J. Gilliland, and an adjoining rear rectangular hall dated 1893 by Thomas Roe.

The principal gable faces northeast and is symmetrically arranged, forming a highly decorative façade. The church is constructed in red brick laid to Flemish bond with ashlar cornice, string and plinth courses featuring varying open-heart, foliated and wedge-shaped mouldings. The pitched natural slate roof is fitted with cast-iron ogee gutters and circular downpipes.

The front elevation features a single-storey lean-to porch comprising a tripartite entrance. The central gable door is flanked by decorative moulded buttresses terminated by gablets. Diminished side doors are flanked by angled buttresses breaking through the eaves and terminated with a plain pinnacle, with a cogged eaves course throughout. The porch is flanked by simple diminutive round-headed windows with continuous impost moulding, moulded brick jambs, and chamfered sandstone cills.

Three round-headed first floor windows are present above, with the central window deeply recessed within a narrow breakfront flanked by decorative buttresses rising above the upper cornice course. These are conjoined by a deep projected segmental-arched canopy surmounted by a brick plinth supporting a decorative moulded octagonal pinnacle bearing the date "1869" and breaking through the gable apex. The front doors are double-leaf timber panelled with deep moulded surrounds and round-headed archivolts with inverted foliated stops. The carved tympanums depict a bust and foliation to the left and right, while the centre tympanum depicts an open bible with crest inscribed "MOUNT-POTTINGER PRESBYTERIAN CHURCH" and "ARDENS SED VIRENS", probably installed after 1873. The round-headed windows are leaded stained glass, flanked by ashlar plain pilasters with decorative stiff-leaf capitals and moulded archivolts. The principal gable features raked coping and string course with brick pilasters surmounted by squat moulded pinnacles.

The left elevation is four bays deep. The right bay continues the front façade and is abutted by a two-storey curved stairwell with decorative machiolations, a conical roof, and plain windows featuring moulded brick reveals and chamfered stone cills and heads. A stepped plain projected stone string course rises from left to right. Five diminishing square-headed windows with cills rising in accordance to the stairs are present at ground level, with five equal-size round-headed upper windows with terracotta panels between the lower and upper windows. The remaining bays to the left are flanked by buttresses, each comprising three square-headed ground floor windows with brick reveals and continuous stone cill course with shared heads. Above are three round-headed first floor windows with deep shared stone cills, brick reveals, and round-headed brick head with projected key blocks. Drop corbelled eaves with cogged course are fitted with ogee moulded gutters with downpipes centred on buttresses. The far left bay is partially abutted by a modern flat-roofed extension of no architectural interest.

The right elevation of the church matches the left elevation.

The rear elevation faces southwest and is abutted by a Romanesque-style gable-ended six-bay two-storey hall erected in 1893. The hall is constructed in Flemish-bonded red-brick walling with terracotta mouldings. The principal elevation faces southwest and comprises a pilastered façade with decorative eaves detail. Square-headed ground floor windows are surmounted by terracotta pediment drip moulding, while round-headed first floor windows feature continuous drip moulding. Recessed central bays are embraced by full-width round-headed arches with paired ground floor windows and Palladian-style first floor windows. Two sets of double-leaf diagonally sheeted timber doors are set into camber-arched openings with chamfered surrounds. The left gable is surmounted by a diminutive pediment bearing the date "1893" with "LECTURE HALL" inscribed on the frieze below. The appearance matches the principal elevation in detailing. The rear elevation of this hall abuts the church. The right gable is very plain with no detailing, with a modern flat-roofed extension to the right.

The church is situated directly on Castlereagh Street and forms a prominent feature in a largely two-storey terraced Victorian and modern residential setting. The front of the site is bounded by robust wrought-iron gates and railings with cast-iron detailing fixed to a sandstone coping. The paving immediately to the front of the church has been replaced with modern stone paviors. Further terraces line the streets to the side and rear, with industrial units adjacent to the adjoining hall.