Kaiapoi is almost Arts and Crafts in style, an elaborate and idiosyncratic Troup Vintage stations. Now greatly reduced in size, it has rusticated weatherboards capped with decorative, intricate half-timbering, and a Marseilles-tile roof with cresting. The verandah, a centrally supported gable-like structure, has a corrugated-iron roof. One of the most prominent features of the station is the turret above a corner bay on the road elevation. There is an elegant chimney in the centre of the apex of the hipped roof. The building is essentially rectangular in form but there is a low gabled extension, the ladies' toilet, at the north end. There is ornate, decorative infill above the T-shaped rail verandah supports at both ends. The six-panelled entrance door on the former platform elevation is framed by slender sash windows and capped by a fanlight. Most windows are sash with multi-pane upper lights. Much of what remains of the interior - fireplaces, tongue-and-groove panelled ceilings and walls and other joinery - is still original.
The main line north from Christchurch opened as far as Kaiapoi in September 1872 and the first station building presumably dated from this time. That building was replaced by the present one in 1904 - preparation of the site began in 1902. Kaiapoi was and still is an industrial town and the station's principal freight traffic was to and from the woollen mills and the freezing works. The building had only minor internal alterations over its life, but on 12 November 1976 strong winds badly damaged the tiled roof on the south of the building. Further damage over the weekend forced staff to move to the north end of the building. After the damage was inspected it was decided that nearly two-thirds of the building had to be removed. The building is consequently much smaller than when it was built. In 1986 Kaiapoi became a special purpose station and it was later relocated to the river bank, where it was damaged in the Canterbury earthquakes.