Riverstone Castle, Oamaru

Located on a small island within a three-hectare irrigation lake, Riverstone Castle is a substantial private residence of approximately 1,250 square metres, arranged over three floors. The building incorporates an extensive range of spaces, including a dungeon and underground tunnels, creating a distinctive architectural response to its isolated setting.

The castle is constructed from solid masonry and clad in large, bolstered Oamaru stone blocks. The substantial construction gives the building a strong sense of permanence, with the finished external walls approaching half a metre in thickness. The use of Oamaru stone also provides a direct connection to the materials and architectural traditions of the wider Otago region.

The design incorporates a series of traditional castle elements, including turrets, castellated ramparts and gargoyles, alongside carved Oamaru stone detailing integrated into the external cladding. These features contribute to the building’s distinctive character while reinforcing its deliberately monumental architectural language.

Four guest suites are located on the first floor, each opening onto large roof decks positioned to the east and west. These elevated outdoor spaces provide areas to enjoy the outlook across the lake and surrounding landscape, while the island setting creates a strong sense of separation from the mainland.

Despite its historic architectural references, the building incorporates contemporary services and infrastructure. The entire structure is heated by a geothermal system laid across the bottom of the lake, using the surrounding water body as an integral part of the building’s heating system.

The combination of solid masonry construction, locally distinctive Oamaru stone and extensive carved detailing makes Riverstone Castle an unusually substantial architectural intervention within its rural setting.