18 Greencastle Street, Kilkeel, Newry, Co Down, BT34

18 Greencastle Street, Kilkeel, is a single-storey post-World War II International Modern house situated in mature grounds on the north side of Greencastle Road.

The house follows a distinctive three-legged radial plan, with one wing running east-northeast, another aligned southwest, and a later addition to the rear aligned northwest. All three legs radiate from a central brick pier of triangular plan, which rises above ridge level and supports pitched concrete pantiled roofs to each leg. The pier itself has a flat roof with plain timber eaves; its rear face is dashed and fitted with a ventilator grill, with a single chimney pot on top.

The front elevation is formed by the roughly south-facing façades of the southwest and east-northeast wings. To the front and right elevation, abutting at eaves level, is a flat copper roof approximately 1 metre in depth with plain timber eaves board incorporating the gutter and downpipes falling from within its painted plywood soffit.

The front entrance sits at the right end of the east-northeast wing façade, accessed through an open pergola porch which abuts the whole right side. The pergola roof comprises a grid of painted timber supported on three circular section painted iron posts. Its left end rests on a stained sheeted timber feature wall advancing from within the house below the flat roof. The fully glazed door is set at the left of the pergola with original letterbox and doorbell and a sidelight to its left; to the right, continuing below the pergola, is a brick feature wall with trellis and climbing plants.

The left side of the east-northeast wing contains four large fixed painted timber picture windows rising to eaves level with a shared cill; the wall below is clad in timber shingles. The façade of the southwest wing features a red brick pier at its left end and thirteen equally spaced rectangular windows rising to eaves level. The three rightmost windows are almost square with a high common cill; the remaining windows are twice the height. The first, fourth, seventh and tenth windows have a square top-hung transom at cill level. All windows share cast-in-situ concrete cills with timber shingled wall below. The end gable of the southwest leg is red brick and blank; the end gable of the east-northeast wing is painted wet dash with timber bargeboard. At left is an advanced bay window with a wrap-around flat copper roof, containing two fixed picture windows on its face and one to its right cheek, with timber shingled wall below.

The rear wall of the east-northeast leg is painted wet dash, with a varnished timber door of original decorative panelling on its left, and a pair of two-paned casements within a single opening sharing a common concrete cill to its right. The remaining wall to the right contains a continuous run of six high rectangular timber windows with a common cast-in-situ cill. The northwest (rear) leg is a later addition dating to the 1970s and is undistinguished in architectural design and materials, of no special interest. The rear wall of the southwest wing is glazed full height and lights an internal corridor.

The property has a planted garden to the front.