10b Blackrock Road, Portrush, Co. Londonderry, BT56 8EX

A detached two-storey seafront dwelling at Blackrock Road, Portrush, originally built around 1910 as a single house and divided into two flats circa 1930. The building is square on plan, facing north, and situated on a steeply sloping coastal site overlooking the sea.

The house is constructed with painted rendered walling beneath a hipped artificial slate roof with synthetic ridge tiles and two rendered chimneystacks topped with terracotta pots. Steel rainwater goods are fitted to boxed eaves. The symmetrical north front elevation is three windows wide, featuring square-headed window openings with simple lugged rendered surrounds, keystones and 2/2 timber sash windows. The lower windows are diminished in size. A large central dormer with paired windows breaks the roofline.

The east side elevation has irregular fenestration and is abutted by a flight of concrete steps and an elevated glazed porch serving the upper level, constructed on reinforced concrete piers. An off-centre dormer window is positioned to the roof, with a further door opening at the lower level fitted with a glazed timber door. The symmetrical rear elevation, set on a split level, incorporates a central dormer matching the front elevation. The west side elevation is abutted by a further glazed entrance porch supported on reinforced concrete posts, opening onto an elevated concrete path to the rear.

The building was initially known as Upper Cooleen. It first appears on the fourth edition Ordnance Survey map of 1922-31. Valuer's records from 1910 show the house entered valuation at £24 with a construction cost of £515. The original occupier was Annie Keith Stewart, living with her niece Annie Louisa Keith Stewart. The five-room house was designated second class in the 1911 census. Following Annie K Stewart's death in 1932, the house was divided circa 1930 into two flats: the upper flat comprised four bedrooms and a boxroom, sitting room, kitchen and scullery, bathroom and WC, with external washhouse; the lower flat contained a reception, two bedrooms, kitchen, scullery, pantry, bathroom and WC. Two glazed porches were added to either side of the house at this time to provide access to the upper flat.

Blackrock Road runs along the lower level to the north and loops around to the rear of the group of houses at a higher level, where a concrete parking area and sunken yard are located. Vehicular access to the property is via the rear.