Situated on the prominent corner of Bompas Road and Cradock Avenue in Rosebank, and with a GFA of 2,800sqm, WDB House will embody an innovative and integrated design for the modern workforce within a healthier, pedestrian-friendly environment. The vision for the Oxford Parks precinct is a sustainable, responsible, mixed-use walkable neighbourhood that builds on the best of what makes the adjacent Rosebank and Illovo neighbourhoods successful.

Janet Glendinning, Development Manager at Intaprop, says:

As the developers of Oxford Parks, we feel that it is important to ensure that buildings are both healthy and environmentally friendly, especially taking into consideration the recent global pandemic. With people now working from home as a preference, healthy spaces will be essential moving forward in order to attract quality tenants. WDB House is superbly well-located and easily accessible, and the carefully considered design has resulted in a multi-tenanted building of a comfortable scale that feels like home.

Responding to its urban context

Because the site is on the periphery of the Oxford Parks precinct rather than right at its heart, the zoning dictated height restrictions, and there was a significant building line on the south of the site to create breathing room between the neighbouring houses and the new office. Kathleen Western, Project Architect for GLH, explains that the Gautrain escape shaft to the east imposed a number of physical and bureaucratic constraints – but this, together with the reopening of the Cradock Avenue link to Dunkeld, allowed the architects to borrow the visual amenity of space, creating a landscaped foreground to WDB House.

A striking, carefully considered design

The brief for the building was a bespoke own-door office building with a striking identity that would allow WDB to consolidate several departments. The client also wanted additional space for the possibility of future growth or current use by related start-up firms.

In responding to both the brief and the various site parameters, Western explains that the architectural response was to create a strong and identifiable presence for the building on the busy street intersection. Efficiency was a primary consideration in terms of structure, space, costs, and the use of resources. The wings of the office space flank a central atrium and, together with the central circulation and service core, create a simple U-form in plan.

The corner of the building is articulated with a setback balcony and overhanging pergola which, together with building volumes in contrasting materials and colours, shape the building’s identity. Part of the parking level was used to create an approach podium to the new building, which obviated the need for mechanical ventilation or a fire sprinkler system in the basements – thus saving the developer capital and operational costs, and reducing the environmental impact of the building.

Good passive design contributes to IEQ

“It is good architectural practice to address sustainability criteria as part of your basic building design,” says Western.

In this case, construction was already underway when it was decided to pursue a formal GBCSA rating. Fortunately, as the building already combined a sensible passive design approach coupled with selected active technologies, it was a relatively simple exercise to document what had been done and to then achieve the rating.

The building faces north and sits squarely on its site. The façade glazing strategy takes into consideration this orientation, views, glare, and thermal comfort; and, together with a process of iterative energy and daylight modelling, shading, window sizing and the glazing specification were refined to ensure a beautiful and optimally performing building. The balcony and terrace feature larger windows, while smaller ‘punch out’ windows on the east and west façades respond to their orientation and provide a rhythm that contrasts with the stone and plaster walls.

Windows are openable, offering individual choice and immediate access to fresh air and a sense of outdoor temperature. Blinds are individually operated, and lighting is individually controlled with occupancy sensors. Lighting power density was limited, and efficient light fittings were installed. A high level of thermal comfort was ensured by addressing the internal operative temperatures through modelling. Priority parking was proposed for LEV, HEV, electrical, and carpool vehicles as well as motorbikes.

Resource efficiency and robust materials

Annelide Sherratt, Sustainable Building Consultant at Solid Green, explains that resource efficiency was a part of the design strategy.

The project has a 14.5kWp Solar PV system with an annual yield of 24.63Mwh installed on the north-east building wing roof; and the building’s HVAC system was efficiently designed and modelled. Potable water consumption was reduced through the use of water efficient sanitary fittings; and through the landscape design and selection of waterwise plants that minimise the need for irrigation.

Materials were chosen to be elegant, robust and long wearing, ensuring value for money in the operational phase of the building’s life. Recycled material components were specified in steel and concrete, and concrete additives were used to reduce noxious materials needed for waterproofing.

All gaseous and fire suppression systems and thermal insulants chosen for the building and façade insulation and pipe and duct lagging have an Ozone Depleting Potential (ODP) of zero. All finishes to the base building areas are low-VOC and, where applicable, were sourced through sustainable stewardship. In addition, a project specific Waste Management Plan was developed and implemented to minimise the contribution of waste going to landfill; and space has been provided for operational waste separation and storage.

This carefully considered building responds well to both its urban context and provides flexibility for the changing needs of people and their workplaces; while taking into account the increasing need for both resource and operational efficiency as building owners face a rapidly changing business reality.