Rock Ryan House, 2 Promenade, Castlerock, Co. Londonderry, BT51 4RF

Rock Ryan House is a detached, symmetrical, three-bay, one-and-a-half-storey former bath house dating from 1862, possibly designed by Samuel Angell, architect to the Clothworkers' Company. It is T-shaped on plan, faces east with a central gabled entrance bay, and occupies a picturesque position between the Promenade and Castlerock beach, built against a rocky outcrop that forms the boundary to the rear garden.

The exterior walls are of random coursed, tooled basalt ashlar with rock-faced quoins. Window and door openings are square-headed with voussoired basalt heads and painted masonry sills. The roof has been replaced in natural slate with terracotta ridgecomb tiles and finials. There is a single asymmetrically placed replacement red brick chimneystack. Two slate-hung box dormers with flat roofs and replacement timber casement windows project from the front roof pitch, with a further slate-hung box dormer to the rear pitch fitted with a uPVC window. Decorative bargeboards have been fitted to all gables. Rainwater goods are uPVC on timber-sheeted eaves, with uPVC downpipes.

The symmetrical front elevation is five windows wide. The central entrance bay has a single window to the ground floor and, at attic level, a smaller 2/2 timber sash window with ogee horns and a semi-exposed sash box. To the left cheek of the entrance bay is a square-headed door opening with a voussoired basalt head fitted with a uPVC door; to the right cheek is a slender opening retaining an original 4/4 timber sash window. The flanking bays retain largely original 6/6 timber sash windows with cylinder glass and no horns. The attic storey of the south gable has a small window opening matching that of the entrance porch. The south gable is abutted by a flat-roofed rendered garage.

The rear elevation is four windows wide with painted roughcast rendered walling. Two square-headed openings in the south bays retain original 6/6 timber sash windows without horns; a further pair of openings has replacement timber casement windows. The northernmost bay has a square-headed door opening with a uPVC glazed door, giving onto a concrete path and a raised lawn enclosed by sheer bedrock. The north gable has a single small attic-level window with painted masonry sill and uPVC glazing.

The building sits on the north side of the Promenade at the west end of Castlerock beach. The front area is surfaced in bitmac and enclosed by cement-rendered walls with replacement timber vehicular and pedestrian gates.

The house was extensively renovated around 1990 and is currently in use as a holiday let.

Rock Ryan has a well-documented and historically significant past. It was originally built as a bathing lodge for Sir Henry Hervey Bruce of nearby Downhill House. It does not appear in Griffith's Valuation of 1859, though a small structure is visible on or near the site on the second edition Ordnance Survey map of 1848. It is first recorded in the Annual Revisions in 1863 as a bath house, the property of Sir Henry Hervey Bruce, Baronet, and valued at £5. The construction date of 1862 is better supported by primary evidence, including valuation records and a rudimentary date plaque, than the alternative date suggested by some secondary sources.

The possible attribution to Samuel Angell is based on his role as architect to the Clothworkers' Company, who owned the Castlerock estate until around 1870 and for whom Angell drew up a development plan for Castlerock in the late 1840s. It appears that some elements of that plan, including the present building, were not executed until some years later. Another architect associated with the Clothworkers' Estates, Frederick William Porter, designed the parish church and modified some housing designs in the area.

Castlerock itself grew as a seaside resort following the opening of a railway halt in 1853, after which the railway company actively promoted development by offering cheap tickets to those who built or bought villas. Sir Henry Hervey Bruce, as local landlord, took a particular interest in this development and required all new buildings to meet a certain standard of quality and size. While Christ Church was under construction, the Episcopal congregation used Rock Ryan as a place of worship.

Around 1915 the bath house was converted into a dwelling, with valuers' notes of that year recording that the old bath house had been "rebuilt" and was let furnished to summer visitors; the valuation rose accordingly to £9. The house was taken over by a Mr Harvey that year. Between 1915 and 1923 a single-storey motor house was added to the south, which appears subsequently to have been replaced by the present adjoining garage. Catherine Tosh purchased the lease in 1928 for £275. At the time of the First General Revaluation in 1933–34, the ground floor accommodation comprised a kitchen, scullery, three reception rooms, two bedrooms and a maid's room, with three bedrooms, a bathroom and a WC on the first floor. Subsequent owners included Mr Murphy in 1940 and Dr and Mrs Thompson during the 1950s and 1960s. The house was listed in 1977, and in the late 1970s renovation work was carried out to the gutters, windows and roof, including repair of bargeboard damage caused by a passing bus.

Rock Ryan is a prominent local landmark on the Promenade, valued for its style, proportions, decorative detailing, T-shaped plan form, setting, and its age, authenticity, historic importance, and associations with the early development of Castlerock as a seaside resort.