The two newest buildings to be built on the intersection of Oxford and Glenhove roads – OxGlen Block 3 and Block 4 – will aim to achieve 4-Star Green Star SA Office Design rating from the Green Building Council South Africa (GBCSA), engineering consultancy Solid Green Consulting senior sustainable building consultant Annelide Sherratt said this week.
The precinct is home to Coca-Cola and Sappi’s South African headquarters. The newest buildings have incorporated many of these buildings’ best performing features, as well as some of their architectural details.
The Green Star process was managed as one multiple building certification, she said.
LYT Architecture architectural director Clive Jearey said he was 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 title and offices are arranged around open, landscaped courtyards that allow the buildings to connect to nature.
The buildings are set far back from the street owing to the Gautrain servitude, which runs below Oxford road. The developer chose to include green spaces and coffee shops to boost opportunities for enjoyment of the urban environment rather than closing it off to the public.
Green Star-rated buildings provide health, wellness and improved productivity benefits for employers and employees, as well as improved energy, water and waste performance. These advantages are achieved through prioritising improved indoor environmental quality (IEQ) with ample natural light and views, fresh air and material choices.
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 and indications of high tenant retention, according to the latest MSCI Green Property Index.
The quantity surveyors at main contractor Barrow Construction estimate that the green premium for the project was 2.44%.
The project was targeting innovation points for financial transparency. Affordably achieving the Green Star rating comes as a result of sound upfront design and incorporating green principles as a matter of good practice, Jearey explained.
“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,” said Barrow Construction MD John Barrow.
Energy modelling was done 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 further ensured through the use of heat pumps for water heating, as well as the use of light-emitting-diode light fittings and occupancy sensors.
Balancing the maximum use of natural light and views, while mitigating glare through effective green office design also has health and wellbeing benefits for office workers, Sherratt explained.
“Water-efficient sanitary fittings have been specified for all bathrooms to reduce daily consumption. 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.”
The OxGlen precinct is near a number of residential developments and amenities, including Rosebank Mall, The Zone, Oxford Corner, Rosebank Fire Station, Rosebank Towers, the Netcare Rosebank Hospital and the Gautrain.
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.
In the courtyard of one of the new buildings is a majestic Pin Oak tree, estimated to be over 100 years old, which had to be protected. This played a large part in the design of the precinct, and the oak 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,” added Barrow.
“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 and improve their experience of the building,” said Sherratt.
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 that sustainability is the new ‘business as usual’, concluded Sherratt.