Award-winning architecture firm Stefan Antoni Olmesdahl Truen Architects (SAOTA) is a dynamic practice whose distinctive work is instantly recognisable. It’s also considered one of the most interesting of South Africa’s new generation of architects, with a high profile at the cutting edge of architecture in South Africa.
OVD 919, nestled below Lion’s Head, this family home capitalises on spectacular views. The OVD 919’s site is excellently positioned on the mountain ridge below Lions Head with views of Robben Island to the North and Camps Bay and the Twelve Apostles to the South.
The Brief was to create a spectacular home which encapsulated the expansive 360 degree mountain and sea views. Though views out were paramount this needed to be carefully balanced with the required privacy from within. The living areas were to be open plan – enhancing everyday life. The architecture needed focus on creating a contemporary, uncluttered and sculptural building.
The Design Team, Philip Olmesdahl, Tamaryn Fourie and Joe Schützer-Weissmann did an excellent job in meeting the clients briefing.
The briefing from SOATA’s Design Team, to our Johan Coetzee, a Professional Structural Engineer, was very clear namely…. the first being a terrazzo-like monolithic floor finish used throughout the main living level; the second being the unique ‘white’ concrete structure of walls and ceilings.
The unique special old weather look concrete, for the structure of walls, beams and ceiling, was a sort off a non-negotiated brief. Johan soon realized that the only way to achieve such a look, was to use a white cement concrete mix, with special aggregates, been exposed by means of sandblasting. The problem was that such type of aggregates was not available in Cape Town area. We ended up using old mined diamond gravel, as the aggregate, which were from the diamond mining area’s from the North West coast of South Africa. The challenge was to design a white concrete, with a 6-9mm pebbled aggregate and to make sure that one can delivered it to site without having problems. The other problem was shrinkage and cracking, due to the small size of the aggregates and white cement. Johan realized that he had to team up with our decorative concrete partner Lafarge…..the rest is history.
Almost the whole of the concrete structure was insitu-casted by the Main Contractor, DDC, using this special white concrete mix, supplied by Lafarge. All the surfaces were sandblasted by WODC, to create the leathered, sandy concrete look.
The biggest challenge for WODC was to precast a total of 92 beams for the ribbed ceiling, using this special sandblasted white concrete mix. There were 32 unique types of these precast ceiling beams necessary, as all services (lighting, HVAC, audio visual, glazing, motorized blinds etc.) would be hidden in recessed spaces behind them. Each beam weighed 835kg and only 14 could be delivered to the site at a time to site. They were lifted off a flatbed truck by a crane and carried to the top of the very steep site where they were carefully lowered directly into position from above. It was not possible to stockpile the beams as double handling would have increased the risk of damage. Each beam was then manually adjusted to ensure it was perfectly aligned….and here our tolerances were max 5mm. The successful result is a first in South Africa.
When we were 60% through the project, the supply of this diamond gravel were stopped by the supplier and we had to source a new supplier. This was a challenge to WODC, but we ended up getting the same type of gravel, from the diamond rich Kimberley area.
The briefing to Johan about the floors was, to install 800m2 white polished concrete floors that ensure a seamless continuity between internal and external living areas and that was in coherence with the sandblasted white concrete walls.
A special exposed aggregate concrete mix, by Lafarge, was used for the steep driveway. The extensive use of concrete, it reiterated as the exposed aggregate finish of the driveway continues into the expansive garages, but in these instances it was used as polished concrete – maintaining the quiet elegance.
All the bollards and curbs were precast and installed by WODC to match the look of the exposed concrete driveway.
This extensive use of concrete, as a decorative building material, is a must to see. All complements to the specifier SAOTA.