The local studio drew on the hexagonal plan of the original 1980s home to create the minimal, linear form of Salt Point Residence, with 185 square metres providing space for two new en-suite bedrooms around a central living room.
"The existing residence is composed of a cluster of hexagonal pavilions. For the new structure, we transposed this hexagonal plan to shape the section for the addition," explained Reddymade.
"The extension was designed to be strikingly simple and minimal, which is reflected not only in its graphic language, but also in its materiality."
A glass corridor leads from the original home to the centre of the extension, where two angled wings meet in a simple living room, conceived as the form's central "hinge".
The long, thin wings then both extend past bathroom blocks towards glazed ends, which open onto private porches to give each of the new bedrooms a close connection with the surrounding landscape.
At the extension's southern end, this porch has been given a mirrored wall fitted with an outdoor shower, facing a cut-out in the wall that frames the landscape.
White walls and ceilings, and pale wooden floors characterise the simple interiors, which express the pitched roof created by the hexagonal section.
While most of the focus on the landscape is via the glazed porches, a series of small windows in the side of the extension give views across the home's gently sloping site.
"The minimal material palette of the extension offers a neutral and light setting for art works and furniture from the client's private collection," said the studio.
"Throughout the new structure, large square windows are set low to frame the outward view and enhance the experience of the home's natural settings."
The artworks that dot the landscape indicate the proximity to Artfarm – a private art gallery designed in 2009 by Swiss practice HHF, also in collaboration with Ai Weiwei.
The metal exterior of Artfarm, reminiscent of agricultural barns, informed the corrugated cladding of Salt Point Home, which from a distance also appears as a simple metal barn until you notice its hexagonal ends.
Reddymade recently worked with Google to design the company's first physical retail space in New York's Chelsea, incorporating cork furniture and recycled materials.
The photography is by Ashok Sinha.