IN PICTURES | This glass getaway has to be SA's most sophisticated country cabin

Less than an hour west of Johannesburg, towards the Magaliesberg mountain range, lies The Cradle of Humankind. About 47,000 hectares here, where humanity's most ancient origins have been uncovered, has been declared a Unesco world heritage site.

Cliff De Wit's parents have retired to the heart of The Cradle on what was once a farm, and is now incorporated within the Khatlhampi Private Reserve, an expanse of wild grassland, natural woodland, dolomite outcrops and bush. "We are able to hear the jackals from the reserve at night," says Cliff. "It feels like you're out in the middle of nowhere."

It's a short drive from a city but a world away - an ideal escape with country roads geared for cyclists, a sculpture park and artists' residency nearby and wildlife from the reserve roaming freely. "We found ourselves visiting every other weekend, and wanted a place of our own here," he says.

One blissful New Year's Eve, he and his wife, Elsje, decided to take the plunge. "A week later we started looking at sites and Cliff's brother Lee started drawing up plans," says Elsje.

Some years ago, Lee designed and built a pavilion on the farm for Wesley, the youngest of the de Wit sons, using architectural language inspired by Mies van der Rohe and Philip Johnson's mid-century glass houses. It was a stripped-down, transparent, minimalist jewel in the landscape.

Cliff asked Lee to design his family's weekend getaway too, taking his cue from the pavilion. The central idea remained the same: to mediate a relationship with the setting and its natural beauty and to pay homage to the complexity of the site through architecture. And to make a comfortable lock-up-and-go home away from home.

A glass box still seemed to Lee, Cliff and Elsje to be the most subtle and complex response to the landscape.

Building to appreciate the surroundings is not as simple as finding a pretty spot and creating a platform from which to admire it. Tens of thousands of years of human habitation, not least the recent decades of farming, have altered the landscape. A modernist-inspired building would not only acknowledge itself as one among many of layers of human intervention, but also frame the views with that awareness in mind.

The famous glass houses that originally inspired Lee were created primarily in response to a natural setting and through their minimalism aimed to blur the boundaries between inside and outside, building and landscape.

The De Wits wanted to be economical in their use of materials as well as space, and Lee came up with simple, ingenious solutions. Instead of floating the concrete roof on pillars at the corners of the slab and glazing a "box" inside the perimeter of the roof, he placed four pillars inside, cantilevered the slab and glazed the length of the building at its perimeter. Sliding glass doors at each end allow cooling cross-ventilation.

The natural shading and temperature regulation provided by the trees keeps the interiors from getting too hot. "In winter the leaves drop and sun shines through, providing warmth, in contrast to summer where the trees create a natural curtain keeping the house cool," says Elsje. "We have continued planting indigenous trees to enhance the organic layer of shade the bush provides."

The columns plunge through the floor to the bedrooms and bathroom below, creating pod-like areas. "A solid four-walled room confines the potential for living space," says Lee. There are blinds that screen off the bathroom or bedroom when privacy is required, but when retracted the rooms extend by over a metre again.

The bathrooms also have a view, and the shower is semi-open and almost cave-like under the concrete roof. It is sheltered on one side by a dolomite retaining wall against the koppie, and a gap between roof and wall peeps up through the vegetation.

"With a weekend house you can afford to be a little more playful than a house you'd live in every day," says Cliff.

"That's why we separated the bedrooms," he adds.

A natural clearing in the forest provided the space for a separate main bedroom. "Cliff installed lighting in the trees to create texture," says Elsje. "We hardly ever close the blinds at night."

The inhabitants are connected to nature. "You're aware of the sunrise and sunset and get a feeling of the phases of the moon," says Cliff. "You're closer to the seasons and in touch with the elements."