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

18 Greencastle Street is a single-storey post-war International Modern house built around 1960, set in mature grounds on the north side of Greencastle Road in Kilkeel. It was designed by architect Kenneth Kenmuir, who had offices in Belfast and Donaghadee, and was built for local businessman Mr Annett, who named it 'Falling Leaves'. The construction and site cost approximately £8,000.

The house displays a striking three-legged radial plan, with one wing running ENE, another aligned SW, and a later addition to the rear aligned NW. Each leg is topped with a pitched concrete pantiled roof that radiates from a central brick pier, triangular in plan, which rises above ridge level. This central pier features a flat roof with plain timber eaves and a single chimney pot to its rear; its rear face is dashed and includes a ventilator grill.

The south-facing elevations of the SW and ENE wings form the front façade. A flat copper roof, approximately 1 metre in depth, abuts the front and right elevation at eaves level, fitted with plain timber eaves board incorporating the gutter and downpipes falling from within a painted plywood soffit.

The front entrance is positioned at the right end of the ENE wing's façade, accessed through an open pergola porch with a roof of painted timber on a grid supported by three circular-section painted iron posts. The left end of the pergola rests on a stained sheeted timber feature wall. The door is fully glazed with an original letterbox, doorbell, and sidelight to its left. A brick feature wall with trellis and creeper extends to its right.

The left side of the ENE wing contains four large fixed painted timber picture windows rising to eaves level with a shared cill; the wall below is timber shingled. The central brick pier divides this from the SW wing façade. The SW wing's south elevation features a red brick pier at its left end, with thirteen equally spaced rectangular windows rising to eaves level. The rightmost three windows are almost square with a high common cill; the remaining windows are twice the height. The first, fourth, seventh and tenth windows have square top-hung transoms in line with the cill level of the three right windows. All windows share cast-in-situ concrete cills, with the wall below clad in timber shingles. The end gable of the SW leg is red brick and blank.

The end gable of the ENE wing is painted wet dash with timber bargeboard. An advanced bay window to the left has a flat copper roof wrapping around from the façade, featuring two fixed picture windows on its face and one to its right cheek, with timber shingle cladding below.

The rear wall of the ENE leg is painted wet dash with a varnished timber door featuring original decorative panelling to the left, followed by a pair of two-paned casements within a single opening sharing a concrete cill. To the right runs a continuous series of six high rectangular timber windows with a common cast-in-situ cill.

The NW (rear) wing is a later one-storey addition dating to the 1970s. It is undistinguished in architectural design and material use and is of no special interest. The rear wall of the SW wing is glazed full height, lighting an internal corridor.

The house retains all original external fabric and is set within a planted garden to the front. It represents a notable example of early International Modern domestic architecture in the region.