Perhaps best known for the impressive slanted glass facade on Oxford road, the precinct is now home to Coca Cola and Sappi’s new South African headquarters. The newest buildings, known as OxGlen Block 3 and Block 4, are located between these offices and have incorporated many of their best performing features, together with some of their architectural details. Senior sustainable building consultant at Solid Green Consulting, Annelide Sherratt, explains that the Green Star process was managed as one multiple building certification.
On this project, Clive Jearey, architectural director at LYT Architecture, comments that he particularly enjoyed being able to consider the whole block as an opportunity to create an interconnected series of buildings, with shared landscaping and street furniture that contribute to a compelling urban fabric. Each block is designed as sectional, and offices are arranged around open, landscaped courtyards that allow the buildings to connect to nature.
It’s a live project that allows for immediate feedback. This kind of constant collaboration unlocks very practical ‘buildability’ benefits.
The project is targeting innovation points for financial transparency and the quantity surveyors at Barrow Construction estimate that the green premium was as little as 2.44%. Jearey explains that being able to affordably achieve the Green Star rating comes as a result of sound upfront design and incorporating green principles as a matter of good practice.
According to the latest annual MSCI Green Property Index, Green Star certified properties have provided better capital growth and higher incomes over the last three years of analysis. There are also substantially lower vacancy rates in certified buildings, which indicate links to tenant retention.
We understand the importance of the Green Star certification from a commercial perspective. Clients are very definitely asking for this kind of independent verification to assess green credentials.
J. Barrow, Barrow Construction MD.
In addition to improved performance in the energy, water and waste sectors, health and wellness and improved productivity benefits are major perks for both employers and employees. These advantages are attained through prioritising improved indoor environmental quality (IEQ) with ample natural light and views, fresh air, and healthier material choices.
Thanks to the Gautrain servitude, which runs below Oxford road, the buildings are set far back from the street. Rather than privatising the space and closing it off to the public, the developer chose to include green spaces and coffee shops to boost opportunities for passive surveillance and enjoyment of the urban environment.
Sherratt explains that the OxGlen precinct is near a number of residential developments and amenities. Cyclist facilities and lockers have been provided for staff and visitors; and electric, hybrid and fuel efficient vehicles and motorbikes have been given preferential parking bays in the basement.
Sherratt adds that energy modelling was done on Block 3 and Block 4 during the design phase to ensure optimum efficiencies, and the buildings surpass South Africa’s mandated energy efficiency standards, showing a 45% improvement compared with a conventional notional building. Energy efficiency was ensured through heat pumps for water heating, and the use of LED light fittings and occupancy sensors throughout. Balancing the maximum use of natural light and views, while mitigating glare through good green office design, also has health and wellbeing benefits for office workers.
Water-efficient sanitary fittings were specified for all bathrooms to reduce daily consumption of this precious resource. Water-wise landscaping and irrigation systems will reduce the anticipated water consumption by about 50% through using smart technology such as rain and moisture sensors, drip irrigation and smart controllers.
In the courtyard of one of the new buildings is a Pin Oak tree, estimated to be over 100 years old and which had to be protected. Jearey explains that respect for the tree played a large part in the design of the precinct, and it forms the focal point for sightlines and walkways through and around the buildings. Preservation of the tree also extended underground, where its ancient roots meant that the entire basement had to be designed around it.
This wasn't always easy. The site shares a common super basement and making the various levels work posed a complicated but interesting challenge to the professional team.
In Johannesburg trees are even more treasured as the city prides itself on being one of the largest man made urban forests in the world.
While sometimes posing challenges to development, the Oxford-Glenhove precinct has revered its history and heritage. During phase 1, a historic trigonometrical beacon that had become covered by grass and rubble, was exposed and restored. While it may look like an old round concrete pillar to most, it dates back to around 1897 when it was erected. It now forms a prominent part of the landscaping of the precinct along Oxford road and is even a geocache location.
OxGlen is a large, iconic development within the Johannesburg cityscape. A Building Users Guide was developed for Blocks 3 and 4, which aims to contribute to optimal operational efficiency by informing building users on how to use systems effectively, which will in turn improve their own experience within the building. The Guide will also inform the way forward in terms of implementing green principles for any refits and expansions. By incorporating green building principles from the outset, OxGlen is helping to emphasise sustainability as the new ‘business as usual’.
A. Sherratt, senior sustainable building consultant, Solid Green Consulting.