Location105 Corlett Drive, Johannesburg, 2196, South Africa
Architect in ChargeAnthony Orelowitz, Carla Soudien, Kate Keightly-Smith, John Peska, Yumna Ismail, Tom Hill
Structural EngineerSotiralis Consulting Engineers - Andries Denner
Quantity SurveyorSchoombie Hartman
Electrical EngineerAftek Consulting Engineers - Sidney de Jongh
Wet ServicesRamsden Consulting - Scott Ramsden
Air conditioningAdaptive Resource Engineering – Carel Schaap
Fire ProtectionTrevor Williams Consulting Engineers – Julius Machaba
Project managersBaseline Project Management – Matthew Rautenbach
Town plannerGavin Edwards
LandscapingInsite Landscape Architects – Karen James
Text description provided by the architects. Design Concept
Project Architect Carla Soudien, describes the conceptual approach: “The concept of the building is derived from a number of sources including the location and context, the choice of materials and the accommodation requirements. The prime site offers an opportunity to generate a jewel box of crafted materials including glass and the Arcelor Mittal Caïman cladding for the cones. Computer software was used to generate a taut collection of forms that challenges the traditional expressions of materials like concrete and glass. Extensive planting on the podium also softens the structure for the inhabitants.”
Carla says the design is based on a glazed box which appears to float, supported by the three conical forms. The cladding provides a glimmering effect that is achieved with changing light qualities. Additionally it could hold the required form while other materials could not. On the north and south elevations a reflective laminated Solarshield S30 glass has been specified. On the east and west elevations a tinted Eclipse Grey Advantage glass has been specified. Ivan Lin assisted with glass specification vis à vis sound insulation, advising that laminated glass could achieve the insulation performance for the allocated budget.
This is a two storey office building sitting atop a 3 storey parking podium, separated by double volume metal clad cone forms. The office space is an elongated flattened concrete and glass form enclosed by wrapped ends, which are punctuated with vertical slits, with the east elevation champfered in plan to follow the site boundary. The conical forms are double volume and include the reception and training spaces. The parking provides for 190 bays.
This rectilinear box is constructed from a brickwork and concrete enclosing element with a coated aluminium infill panel. Below this are panels of African Blue Slate Riven Walling as a contrasting ‘band’ to break up the scale of the basement’s bulk.
External floor finishes
Polished concrete walkways with a saw-cut pattern and inlays of slate tiles are placed at the entrances, in a pattern similar to the riven walling on the basement façade. Beyond this lies the infill landscaping which is xeriscaped using indigenous, low maintenance plants with tall grass-like planting on the perimeter to soften the edge of the building and the balustrades. The roof landscaping matches the ground floor podium with a combination of polished concrete walkways and similar planting.
Concrete and glazed office box
The concrete box form accommodates two levels of offices and is characterised by its wrapped ends with striking slot windows making vertical ‘slashes’ in the form. The dark glass in the slot windows contrasts with the matt texture of the concrete box.
The main glazed façades are single glazed in a slightly reflective glass, in an effort to move away from a very black glass which complies with heating, cooling and glare requirements, but without compromising on performance.
A network of steel columns is clad in a layer of galvanized sheeting which forms the weather line with the final cladding of the silver CaÏman on a special sub structure made up of ‘omega rails’, which forms a gap between the cladding layers for ventilation. The steel structure was workshopped between structural engineering, a 3D model of the steel structure submitted by the steel sub-contractor and overlaid onto the Revit model for co-ordination and then approved. This proved to be challenging to co-ordinate the process between steel, cladding and glazing subcontractors, with each junction being unique because of the unusual forms.
The glazing in the cone forms is a highly reflective glass Solarshield S10 Silver, for the narrow strip windows and dark glass at the entrance shopfronts to accentuate the folding forms of the cones.The roof cones have a lightweight sheet roof on a steel structure with a flat concrete roof over the stairs and lift shafts.
The internal walls of the cones are skimmed and painted dry walling, in sculptural forms which appear to be folding and pull away from the structure in places to make dramatic envelopes of space. The windows are punctured in the walls, with slanted sills and tapered reveals, with an almost Gothic feel.
Each cone has a band of lighting at the base and head to create a sensation of floating, so that at night they appear to be detached from the concrete forms above and below. The ground floor podium has winding strips of cold cathode lighting in the soffit which will lead the user to the entrance doors and enhance the playful forms of the cone structures. The reception cone has a striking barrisol light insert in the ceiling bulkhead to create a ‘spaceship-like’ glow.