Recently completed in Rondebosch, Cape Town, The Augusta – a 5 000m² multi-storey residential property – proposes an inhabited and abstracted ‘mountain’ as homage to its context and the Table Mountain backdrop.
The site is at the confluence of major arterial roads and near the corner of the vast open space of the Rondebosch Common. It is a transitional zone between low-, medium- and high density sub-urban built fabric. The surrounds contain individual houses, many of which were designed in the Arts & Crafts era with timber detailing, as well as row houses, small apartment buildings and a number of medium rise apartment towers, including some fine examples of Art Deco blocks. This is all contained in a strongly treed and planted environment. The site affords panoramic views in all directions.
The studio was approached to design a residential development, replacing the former derelict Arts & Crafts house and introducing high-density urban dwellings.
Site constraints and response
The constraints on the site included various town planning setback requirements at different levels and that the resultant building needed to recede progressively with height.
Rather than organise the building along the perimeter and shape of the plot with long circulation passages, the studio took on the challenge of creating desirable apartments and terraces at the higher levels and setting the apartments back as far as possible from the surrounding boundaries and buildings.
The solution was to embrace the opportunity to use available height and to develop a series of receding, floating platforms above a base urban form, and in so doing to celebrate this with a more vertically oriented circulation core. The building would therefore read as an articulated stack of inhabited spaces referencing the immediate- as well as wider urban-, sub-urban- and natural contexts.
The experience of visiting the building – its approach and movement through – seeks to enact the experience of climbing Table Mountain. It involves rising up through a metaphorical wooded ravine or kloof, to pass through cracks and ultimately arrive at a flat mountaintop with rock pools.
In keeping with the concept of the architecture as a deconstructed mountain, movement is thus structured as a ritualised and repetitive enactment of climbing, referencing the human use of the surrounding natural landscape and the habitation of its ecological niches since primordial times.
The process begins with a slight descent into an outdoor soaring atrium as a planted ecological niche. It than progresses through a series of staircases that double back and break out above the tree line with views onto the surrounding landscape.
A vertical shaft of planting rises the full height of the atrium and is reminiscent of tight, mossy and wooded crevices. The terraces and ledges on the upper levels of the construction recede and mimic deep rock shelves. The experience of climbing culminates on a roof terrace and pool composed of abstracted floating planes and a crystalline body of water.
The architectural response
The architectural response is to set up a clustered system of frames that create vantage points from which to survey the landscape. These represent a contemporary analogy of the eye, or ‘oog’, of a seasonally habitable cave.
The frames are alternated, overlapped, engaged and embedded to form a woven three dimensional, deep matrix. There is a rhythmic syncopation that plays off the underlying structural and spatial orders. The rotated fin walls at the corners of the frames provide inflections that direct primary views out of the apartments.
The frames echo the reading and transient use of landscape through the lens of the Cape’s spatial archaeology. The frames can also be regarded as abstracted virtual ‘addresses’ in the sky – a pixelated pattern reflecting the urban locus of human habitation in the information age.
Secondary layers of vertical striations by means of recesses and timber wall elements – as analogical or abstracted ‘trees’ – echo the wooded nature of the site, its wooded surrounds and the forested eastern face of Table Mountain. Close up, the walls, terrace surfaces and timber cladding seek to emphasise a tension between abstraction and the experience with a tactile materiality. This materiality also references the numerous Arts & Crafts era buildings in the immediate surrounds. The geometric formality similarly responds to a number of nearby Art Deco buildings.
The internal spaces are arranged as architectural journeys from front door to terrace, and each room has a primary locus from which to survey the outside landscape. The illuminated kitchen counters structured around the ovens and cooking surfaces are a contemporary rendition of a cooking hearth, and the carefully arranged media walls in the open plan living areas are an analogue for the focus point of a virtual open fire.
The building seeks to make its physical bulk become transformed at dusk and as night falls so that it becomes de-materialised, ethereal and floating.
Technology and construction
The design process entailed careful multidisciplinary engineering and optimisation of structural, services and energy efficiency. The overhanging frames and recessed glass lines inherent in the design assisted in achieving a good performances in both Annual Energy and Demand Intensities with a rating approximately 7% better than the XA analysis benchmark targets. The domestic hot water system is by means of a centralised heat pump. LED lamps throughout and movement sensors also contribute to reduced demand. Separate hot and cold-water taps, rather than mixers, for example, allow users the option of avoiding unnecessary hot water consumption at sinks and basins. All drainage was by means of integrated, concealed stacks in shafts using a branch and ball system for soil and waste.
The construction process was fast-tracked with the use of post-tensioned slabs, and the rapid process entailed the installation of kitchen, for example, while upper-level slabs were still being cast.
The complex structural design, despite the relative lightness of the majority of the slabs, needed a compensating transfer slab at the fifth floor, which was also partially the outcome of anti-seismic requirements and to counteract interacting deflection. This involved a significant single continuous pour lasting nine hours and totalling 530m3 of concrete using two boom pumps at opposite ends.