Fortwilliam Fold, 30 Fortwilliam Park, Belfast, Co. Antrim, BT15 4AN

Fortwilliam Fold (formerly Rosaville) is a detached, multi-bay, two-storey red brick and stucco Italianate mansion with a three-stage tower, built around 1869 to the designs of the architectural partnership Boyd & Batt. The practice was formed between John Boyd and William Batt around 1862, with offices in both Londonderry and Belfast, and was known for commercial, ecclesiastical and domestic work. The house was commissioned by Hugh White, a local wine and spirit merchant who also owned White's Tavern on Winecellar Entry, and its construction cost £2,600. It stands on the north side of Fortwilliam Park, one of the residential plots created when the Fortwilliam Estate was broken up in the mid-19th century. The park was laid out around 1864 and a number of grand mansions were erected on the former estate during the 1860s and 1870s, though only a few now survive, including this building and the Dominican Convent. No. 30 is among the most impressive of the surviving gentlemen's residences, and its elevated position and exuberant stucco detailing give it considerable grandeur, reflecting the stature and ambition of its original occupants.

The house is irregular in plan and faces south, set within its own grounds on a slightly elevated site. Roofs are hipped natural slate with lead ridges and valleys. The corbelled red brick chimney stacks have terracotta pots. Moulded cast-iron guttering is carried on heavily bracketed eaves, with replacement steel downpipes. The red brick walling is laid in Flemish bond and features a projecting moulded render plinth, stucco quoins with indented panels rising to the level of a stucco plat band between floors. This indented panel detail is repeated in the stucco architraves around the round-headed window openings at ground floor level, which have decorative keystones, while the first floor windows are segmental-headed. Windows throughout are original single-pane timber sash with horns and moulded stucco sills on corbels. Some historic glass survives in the first floor windows.

The principal south elevation features a full-height bow with a semi-conical roof, in which curved-arched windows are arranged in groups of three at each level. To the west of the bow, windows are arranged in pairs at each level. Immediately to the east of the bow is the three-stage entrance tower, described further below.

The west elevation is six bays wide in total. The three southernmost bays continue the same stucco detailing and Italianate character seen on the main frontage. A single-storey projecting bay at ground floor level is surmounted by a moulded heavy cornice and a pierced stucco balustrade; this projection has paired windows to the front and slender round-headed window openings to the cheeks. It appears — though this is unconfirmed — that the original house may have extended only as far as this projection, at the point where the eaves step down and the moulded plinth and plat band are discontinued. Alternatively, the three-bay, two-storey red brick return to the north may have served as servants' quarters. This portion of the building is noticeably more modest in character, with shallower eaves and smaller segmental-arched window openings with plain stop-chamfered architraves.

The rear north elevation is abutted by a three-storey rendered stairway projection at the centre, which steps down to a two-storey block to the east and a later three-storey brown brick return to the west built around 1985.

The east elevation is dominated by the three-stage entrance tower at its centre, the entrance of which faces south. The tower has a pyramidal natural slate roof with decorative brackets and a panelled frieze. The lower stage has panelled stucco quoins, the middle stage plain quoins, and the upper stage clasping Doric pilasters. Slender round-headed tripartite window openings with decorative panelled architraves, keystones and moulded sills on corbels appear on the north, east and west faces of the upper stage, and on the east face only of the lower two stages. To the north and south faces of the tower are round-headed door openings, each flanked by panelled stucco pilasters with stiff-leaf capitals, and each with a moulded architrave and keystone to the glazed fanlight above. The south entrance has a replacement timber panelled door; the north entrance retains its original timber panelled door with the upper panels glazed, though this entrance is no longer in use. Directly above the south entrance door at first floor level is a bull's eye, or oeil-de-boeuf, window opening, which is bricked up; this opening has a panelled stucco architrave with a keystone at the top and block stones at each of the remaining three axes. The plat band between ground and first floor and the projecting fascia at eaves level are carried around the three exposed faces of the tower, unifying the overall composition. Paired windows flank the tower on either side, detailed in the same manner as those elsewhere on the building. A steel fire escape is located to the north. The south entrance opens onto a concrete-paved platform enclosed by a low rendered wall, with a flight of concrete steps leading down to the parking area to the east.

The listing covers the house together with its gate pillars and boundary walling. The property is set back from the road on its slightly elevated site, enclosed by a low plinth wall topped with stone coping and iron railings that sweep between square pillars at the boundary to octagonal masonry pillars supporting replacement steel gates. There is a bitmac parking area to the west, reached via a bitmac driveway from the road. The rear returns are connected to a large L-shaped three-storey block built around 1960, with the three-storey extension to the rear added by 1985 to provide additional residential accommodation. The grounds contain mature landscaping and trees.

Hugh White was the first occupant of the house, then known as Rosaville, and the 1870 Annual Revisions set its total rateable value at £90, noting that the site was leased to White by William Valentine of Fortwilliam House. The Annual Revisions also included a sketched plan of the building closely matching the current ground plan, depicting the three-storey Italianate tower and the rounded bay to the south elevation, and showing that the building originally possessed extensive outbuildings to the rear — since replaced by the modern extension. Hugh White continued to live at Rosaville until his death in 1882, after which the villa passed to his widow, Mary Jane White. By 1893 the house was occupied by Edward McKean, employed as a commissioner of the Central Chinese Customs Service. The 1901 census described it as a first-class dwelling of 16 rooms, with a stable, coach house, cow house and fowl house among the rear outbuildings. Edward McKean had purchased the property outright by the 1930s and leased it to other occupants. Under the First General Revaluation of Property in Northern Ireland (1936–57) the rateable value remained at £90, though it had risen slightly to £97 by the end of the Second Revaluation, when the occupant was a Mr F. Hanna. The building was listed in 1987 and reroofed around 1988. It was converted into Fortwilliam Fold in the 1990s and continues to be used as a residential fold for senior citizens, comprising 37 self-contained apartments.