This passive solar new-build house on the edge of the Great Karoo desert in South Africa acts as a poetic and flexible agricultural object, a harvester of light and air, which is adjusted by its inhabitants in response to the changing natural elements.
Key elements of the brief were: to bring the inhabitants into a closer relationship with and awareness of the natural world – the spectacular natural landscape of the Swartberg and the Karoo – along with changes in light, heat and wind, at different times of day and during different seasons; to focus on passive, rather than active, means to heat and cool the building, with a ‘fabric first’ approach to the design and planning of the house; and to use local labour and materials which connect with the traditional of building in the Karoo.
In the light and intense heat of summer the thick-walled house can be shuttered, while in winter the large openings act as suncatchers, allowing the dark brick floors to radiate the stored warmth of the sun in cool evenings.
The 230m2 house was built by local builders, and was completed for less than £200,000. It uses a limited palette of robust materials, which connect to the previous use of the site as a sheep farm – brickon-edge floors, ash, local roughcast lime-washed plaster and white ceramic tiles.
The day/night, light/dark character of the house is emphasized by large glazed doors, which slide away into roughcast plaster walls, and small scattered openings, which allow shafts of light to penetrate into shadows, and are configured according to the positions of stars in constellations visible from the upper roof terraces.
The large elevated roof terraces act as a modulated raised ground surface. They foreground far views of the mountains, and bring the inhabitants closer to the clear, star-filled skies.
The house is located on the outskirts of the town of Prince Albert, at the foot of the Swartberg Pass, a World Heritage site.
The shifted geometries of the plan are a consequence of arranging the spaces in response to the surrounding landscape: the volumetrically differentiated rooms are inflected relative to one another in order to capture specific views of the mountains and grasslands. The far views of the Karoo to the north and east are balanced by the rise of the mountains to the south. To the west the house is more opaque, screening out the burning summer light, while the upper terraces allow views to the sunsets, and the town, at cooler times of day and in the winter.
In line with the low energy use and low technology requirements of the brief, the house avoids sophisticated installations for heating and cooling.
Temperatures range from 40 degrees celcius in the summer to minus 6 degrees celcius in the winter, so the house had to accommodate a large range in temperature using passive techniques.
It therefore relies on the fabric of the building - thick insulated brick walls giving a high thermal mass, dark brick floors to retain heat in winter, double-glazed timber windows, high level ventilation into high volumes and sliding timber shutters, to modulate temperatures.
The east-west orientation allows the principle spaces to take advantage of the sun from the north, while large openings to the south enable views to the mountains.
By using the responsiveness of the structure to the environment to develop a poetic and material language for the building, along with the positioning and orientation of spaces towards the landscape, the house becomes inseparable from its context. It also allows nature and landscape to become part of the ephemeral materials of the house. The layered volumes and spaces of the house have a loose structure that is intertwined with the loose structure of the landscape: the far hills of the Karoo and the peaks to the south.
The stepped profile of the house against the landscapes of mountain and veld continually shifts from different viewpoints, allowing connections to be made between the context and the external form of the building.
The appearance of the house alters as the shutters and large sliding doors are opened and closed in response to inhabitation and the environment.
The sectional variations of the internal spaces are reflected in the varying external forms of the house. The highest space, the living room, encloses a perfect cube, with ceiling heights at 5.7m. The height enables the room to vent through high level pivoting shutters (operated from the first floor roof terrace), which bring in cooling winds from the south.
The first floor roof terraces allow for circulation around the raised volumes, while the uppermost terrace is located above the smaller ground floor bedroom, and looks to the west - to the town and the sunset.
The patterned brick-on-edge floors and roughcast plaster walls and ceilings are kept consistent throughout the exterior and interior spaces, allowing for an ambiguity between inside and out. They are deliberately non-domestic and unrefined.
The finely detailed joinery, made in oiled ash, acts as a counterbalance to the more robust materials and differentiates between the sculptural qualities of the solid structure and the elements made to be touched and used in everyday life
The lack of light pollution in this remote location guides the way in which an awareness of the stars and the clarity and colour of natural light has become an intrinsic part of the design of the house.
Changing light patterns shine through shutters during the day.
Shafts of light from scattered openings, positioned with reference to celestial constellations, provide daylight and become light sources at night.
Concealed LED strips are integrated into external and internal openings, so that the openings in the structure of the house itself illuminate the interior. From the exterior, the house is lit with an irregular pattern that is in sympathy with the scattering of stars in the dark skies. The landscape of mountain and veld is integral to the design and experience of the house. Openings and spaces are designed to bring near and far landscapes into the way in which the house is experienced, collapsing the distance between nature and everyday life.
Openings are aligned through and within the building so that the heaviness of the rendered walls is interrupted by large, delicately framed openings, through which the natural environment is visible. The pool is enclosed by a stone wall selected to match the colour of the mountains. It recalls the dry stone enclosures used for livestock in the local area. It is intended to provide a secluded world for contemplation, without distraction.
The house counterbalances solidity and transparency, light and shadow. The sliding shutters can screen out light and heat - or open to admit warmth, air and views to the external landscape.
The roof terrace forms an alternative ground plane, which allows the landscape to be integrated further into the house. Circulation around and above the double height volumes enables the roof to accommodate a series of outdoor places that can be used during different weather conditions and at different times of year.
The first floor bedrooms open onto the fire circle and seating area, which is screened from harsh west light in the summer and from the wind, which blows on hot afternoons.
The roof terraces embrace an openness to the sky and the abundant stars and are used as gathering places on warm summer evenings. The house not only defers to the landscape, but is also formed by it, therefore developing a poetic architectural language, which brings its inhabitants closer to the natural world.