Seamount, 19 Circular Road East, Cultra, Holywood, Co Down, BT18 0HA

Seamount is an unusual suburban house built in 1924 to designs by Thomas Francis O. Rippingham, chief architect to the Ministry of Finance. This is a rare example of domestic architecture by an architect best known for his public buildings, including police stations, post offices, Stranmillis College, and housing estates. The house was built for a colleague at the Department of Finance.

The building is a detached two-storey three-bay house with an L-shaped plan and a two-storey entrance block located at the re-entrant angle. The steeply pitched tiled roof features stylised Dutch gables and overhanging boxed eaves supporting cast-iron rainwater goods. Two tall rendered chimneystacks, each without caps or mouldings, carry three terracotta pots. The entrance block breaks the eaves line and rises to a flat roof concealed behind a panelled parapet with flat masonry coping and spherical masonry finials at the corners.

The walling is painted and rendered with a contrasting plinth. Windows are principally 8/8 horned timber sashes with exposed boxes to the ground floor and plain rendered drip moulds over. First floor windows are double-hung multi-paned timber casements; those to the principal gables are round-headed with spoked toplights, while the entrance bay window is rectangular and set in a wider recess with a voussoir-styled head formed in render. Casement dormer windows (single to north, double to east) are recessed into the eaves with gutters bridging the gap. Window cills are flush bull-nosed timber, set into the window reveal with a recess beneath—an unusual but assured detail characteristic of the design.

The principal elevation faces south and is L-shaped with a central entrance block; the right bay projects and is gabled with a window to each floor. The entrance tower contains a multi-paned glazed timber door with a window over. The left bay has a window to ground floor only. The west gable has a window to each floor. The north elevation has three windows to each floor, with first floor windows recessed into the eaves; all are set to the left side, with one modern casement insertion with obscure glazing. The east elevation has two first floor windows; the ground floor has a window to the left side and two timber sheeted doors—one to an outside toilet and one to the kitchen—with a window between them. An early twentieth-century water pump is fixed to this wall. At the extreme left side, the eaves extend to form a screen with a round-headed arch leading to a paved path to the entrance.

The house is distinguished by a compact plan form, neat proportions, and stylised Dutch gables with unusual window detailing. The design caused considerable comment locally when built; a 1933 valuer described it as "Modern. Extremely ugly house – modernist or foreign architecture," though by the early 21st century it was recognized as unusually attractive.

The house is set close to the road in a large mature garden setting bounded by hedges and trees. To the east is a gravel parking area and garage, accessed from the road by a pair of modern timber sheeted gates. The listing extends to the house and outbuilding.