'Arleston', 21 Old Mountfield Road, Omagh, BT79 7EH

Arleston is a detached symmetrical three-bay two-storey house built around 1855, located on the south side of Old Mountfield Road, Omagh. The building remains largely intact in plan form, massing and proportion, and retains much original detailing, though a number of alterations and extensions detract from its overall character and interest.

The house is rectangular on plan facing east, with a two-storey return and single-storey extension attached at the south adjoining a further perpendicular range of outbuildings aligned north-south. The pitched roof is finished in natural slate with blue and black clay ridge tiles. Two smooth rendered and painted party-wall chimneystacks carry decorative clay chimneypots. A projecting corbelled eaves course supports u-profile cast-iron rainwater goods, and decorative carved bargeboards to the gables are supported on projecting rafters.

The walls are ruled-and-lined rendered with a projecting plinth and projecting string course to the canted bays. Windows throughout are 2/2 horizontally divided timber sliding sashes with projecting painted masonry cills. The principal elevation faces east and features a central single-storey entrance porch with chamfered corners, flanked by two-storey canted bays on each side. The porch contains an original six-panelled entrance door with modern altered fanlight and original ironmongery, accessed by a single stone step, with windows to each cheek. Above the entrance is a wrought-iron balcony accessed from replacement timber doors at first floor. The canted bays have hipped natural slate roofs with leaded ridges and ogee profile cast-iron rainwater goods, with windows at each cheek at each floor.

The left gable is abutted at its left by a single-storey conservatory. Two dipartite windows appear at the right (with the left divided by the conservatory wall), and two dipartite windows at first floor are surmounted by a continuous hoodmould with label stops, with a small semi-circular hoodmould at the apex. The rear west elevation is abutted at its centre by a two-storey pitched return. The west elevation has scattered fenestration of mixed window types, with access through a replacement timber entrance screen at the left and two original timber sliding sashes at the right (the left stained glass, the right diminished). At first floor centre is a square-headed stained glass window flanked by a timber sliding sash to the right and a timber casement with margin lights to the left, with a diminished timber casement with margin lights at the apex. A re-entrant angle at the left is abutted by a two-storey flat-roof extension, while a re-entrant angle at the right is abutted by a single-storey extension. The right gable is detailed as the left but without the conservatory. The two-storey flat-roof extension has a replacement timber casement at ground floor and a dipartite timber sliding sash at first floor on its west elevation, with a blank north elevation. The single-storey extension is detailed as the main house with a red brick corbelled chimneystack carrying a clay chimneypot, a single stained glass timber sliding sash to the south, and a single square-headed timber sheeted door with transom light to the north. The west gable is abutted by a slightly higher single-storey extension detailed as the main block with a central red brick chimneystack. The north elevation contains a through passage to the courtyard and garden at the left, with exposed sections containing three square-headed timber sheeted doors and two 1/1 timber sliding sashes. The south elevation is abutted by two lean-to glass houses, and the west gable adjoins the perpendicular range.

According to historical records, the house first appears on the second edition Ordnance Survey map of 1854, uncaptioned and without a driveway, suggesting it may have recently been completed. By the third edition map of 1906, it was captioned 'Riverdale' and had been extended to the rear with various outbuildings added. On the fourth edition map of 1935-7, it was renamed 'Arleston'. The building is listed in Griffith's Valuation as a house with offices and land, valued at £20 and later amended to £25, with the occupier James Scott and lessor George Buchanan. In 1864 the house passed to A C Buchanan in fee, and in 1888 King Houston leased it from Lewis Buchanan.