Montrose 9141

The site was divided by the existing driveway, which rose steeply from the end of the cul-de-sac below. The new building’s form, perched as it is in a commanding position, was perceived from the outset to be a pavilion overlooking the lawns and the forested valley below.

The clients’ brief had a few specific requirements, but for the most part they left the resolution of this challenging site to the architects. An earlier project by this practice, featuring a floating winged roof, was to provide influence as was the privacy of the first floor master-suite, living room and kitchenette. Orientation towards the Constantia Valley and distant False Bay, and the dramatic views up the mountains above Kirstenbosch, were prerequisites, as was the emphasis on developing the site to maximise the garden and lawn area.

The clients’ succinct brief indicated that an unconventional approach was in order. The first decision was to relocate the driveway to the southern boundary of the site to allow a south-entry, north-facing layout, to open up the lawns and the gardens towards the sun and mountain views. There are panoramic vistas towards the south and west from the bedrooms and living rooms; while the pool and terraces are located on the north-east side, in a courtyard protected from the Southeaster gales by the intersecting linear forms of the house.

The triangular shape of the site, and its elevation above the street and steep incline, required extensive excavation and retaining, in order to provide a driveway of acceptable gradient, and extensive building platform on one level, and garden terraces all round. All had to comply with regulations. Ground water wand clay soil conditions proved challenging for the engineers seeking solid foundation for the exceptional, proposed unusual building.

The first floor is linked to the ground floor living areas by the double-volume spaces of the entrance hall passage and stairwell. The living areas are separated over two floors but connected visually and audially by the glazed voids.

The required water feature element was literally interpreted in the linear installations, which forms the main access of the layout. Water leads in from the driveway, across the front door bridge and then changes direction to focus down the passage, towards the mountain views and staircase. This extended water feature runs continuously into the swimming pool on the northern side of the outdoor living area.

The client had a few specific requirements from the outset: polished granite floors, no carpets, no curtains and the floating feature roof with clerestory lighting. Most of their furniture was already in storage and their preference was towards a slick modernist environment with a definitive northern European flair. The imported light grey granite floor slabs set the tone for a colour palette of cool greys rather than natural browns, a refreshing change from prevailing trends.

The double-winged roof, floating above the bedroom wing, and virtually glass box-enclosed living rooms, are the main architectural features. They are complemented by various secondary architectural elements such as the cantilevered end of the main entrance feature wall, the floating stone-clad fireplace, continuous perimeter cantilever terraces to the bedrooms and the wrap-around cantilever eyebrow.

All these elements are joined by the extended glass envelope and clerestory, which follow the rectangular form of the building. The deliberate absence of concrete or brickwork columns, lead to the incorporation of steel columns within the glazing line.

The floating roof is, very bravely, solid concrete, resting only on these steel columns. The benefit being additional stability to the lateral forces on the support structures. Many elements such as the dog-legged concrete stringer and tread staircase, and the extent of the unsupported slabs and concrete eyebrows required challenging precision engineering. Not forgetting the aforementioned concrete roof and steel columns.

The home is fully automated with high-echelon German technology, including lighting control, B&O audiovisual and surround-sound systems. Water-based under-floor heating shares a heat-pump with the pool and a generator ensures power in the case of winter load shedding. Joinery and cabinetry throughout is custom made in black and white high-gloss automotive spray paint and black granite, forming contrasts with the grey palette of walls, floors and aluminium detailing. All painted surfaces were hand-trowelled with textured paint, with an overall matt finish that again complements the polished grey granite floor slabs and glass balustrades.

“Neither the clients’ brief, nor their informed indications, required a conventional approach to plan, form or function. The site and location is spectacular, a modern pavilion with little reference to suburban or residential aesthetics or styles, seemed fitting,” says partner, Stefan Antoni. The totally covered area, including terraces, is 673m2.