135 Whiterock Bay, Killinakin, Killinchy village, Newtownards, Co Down, BT23 6QA

135 Whiterock Bay is a two-storey International Style house built around 1936 by Philip Bell, a pioneer of the modern movement in architecture in Northern Ireland. The house stands on a slight rise on the south side of Whiterock Bay Road, overlooking Strangford Lough, roughly a mile west of Killinchy village.

The building is roughly square in plan with a cubist form, finished in rough cast and painted. It features flat roofs with large overhangs and is composed of interlocking blocks influenced by early twentieth-century German modernist design. The front north facade has a glazed door with steps and a flat-roofed open porch supported on a single thin metal pole at its centre, with a small porthole window directly above. To the right are two square windows (one to each floor), and to the left a projecting bay with large corner windows to each floor and a further square-ish window to the first floor only. The west facade includes a small single-storey projection with a flat roof and glazed door, with a small intermediate-level window to its right. The lower section of this facade extends to the rear. The eastern chimney stack is rendered; the western stack has been removed. Metal and PVC rainwater goods are present. The window frames are all timber replacements, installed before the time of listing.

The house was originally one of four built as weekend accommodation for visitors to the adjacent Strangford Lough Yacht Club. The four properties were constructed around 1936 to complement the yacht club, with which Bell was simultaneously engaged. The houses were reportedly built during high tides that prevented work on the clubhouse itself. They were designed without running water or electricity. This particular house was later acquired by the yacht club to serve as the steward's quarters, a function it continues to fulfil. Two of the three companion houses have since been substantially altered. The club itself has been replaced with a contemporary building.

The exterior and boundary remain intact. Internally, the house retains most of its original fittings, including stairs, doors, and flooring. The listing extends to the house, gates, and walling. This is a rare example of International Style architecture in the province, and the building group retains significant historical and architectural value.