Completed: 2021, Linbro Park, Sandton, Johannesburg
Stationed inside Sandton’s scenic Greenlee Eco-Estate, the six-star Green Star-rated Greenbarn leisure project, developed by Balwin Properties, consists of simple initiatives that contribute to the sustainability of the entire estate. Rooted in nature, the traditional rustic farmhouse-inspired design is more than just a lifestyle centre. Home to a plethora of amenities such as an outdoor gym, laundromat, food garden, art gallery, and so much more, the site boasts all the fabulous features that make communal living a pleasure.
Combining their focus and grasping the opportunity to make a difference in the green building sector, the multi-disciplinary teams involved on the Greenlee Greenbarn development exercised design excellence and thinking at every level of the project to enhance the end-user experience, build a sense of community, and progress the inclusion of sustainable principles in high-density urban developments. To that end, the ‘greenbarn’ building initiative aspires to introduce family-oriented lifestyle centres into each estate within the Balwin Properties green brand portfolio. The wholesome, accessible, and shared recreational facilities provide amenities such as pools, outdoor soccer pitches, an inside gym, a fresh-produce store with a working potager garden, co-working and exhibition spaces, children’s play areas, and large garden chess sets. This ties in with the urban design of each development, which encourages community outdoor activity through the estate’s purpose-planned green belts and pocket parks.
The first two Greenbarn prototypes have been completed at Greenlee Eco-Estate, Sandton, and Greencreek Lifestyle Estate, Pretoria. The third edition is underway at Greenbay Eco-Estate in Gordon’s Bay and is set to be completed in September 2022. The scale for determining the size of each location’s Greenbarn structure is approximately one square metre per apartment in the development. For example, if an estate has 1800 apartments, the constructed Greenbarn will be built with a floor area of 1800 square metres. For developments like Mooikloof Mega City, which consists of five lifestyle estates, each residential project will have its own Greenbarn complex.
The evolving design behind a Greenbarn project is influenced by each site’s specific context and requirements. However, while some of the details vary, the concept of creating a centre for community participation, activity, and connection stays the same. Another key objective in the Greenbarn concept is to make the elements of sustainable design visible so that they serve as demonstrable landmarks of green building principles. By exposing and showcasing every eco-conscious intervention and making it part of the development’s aesthetic as opposed to submerging these features in the fabric of the building and surrounding landscape, the value and importance of sustainability is shared by the whole community. For example, the solar panels are deliberately placed on an angled roof so that the system providing natural energy is visible; harvested water from the stormwater drains is channelled into three attenuation ponds that are landscaped as part of the Greenbarn outdoor environment; and the collection of rainwater into large, feature water tanks used for the potager garden not only optimises water efficiency but also helps to grow vegetables for the deli and the fresh produce offering in the convenience retail outlet. Overall, this approach seeks to foreground green design as a living principle that will influence greater awareness, ultimately changing everyone’s behaviour.
The scale and volume of the Greenlee Greenbarn development allow for increased open space and access to the outdoors with plenty of natural air circulation. Two frames with a central lobby form part of the core floorplan, highlighting its unique sense of place. The nine-metre-wide entrance from the boulevard leads through five-meter-high barn doors that open up directly onto the indigenous landscaped gardens with an adult leisure pool and separate, enclosed children’s pool. In the centre of the lobby, a wild fig tree has been preserved as part of the process of integrating the Greenbarn into its environment. With 80% compliant vision glazing, the building enjoys the sweeping views of its interior and surroundings. The terraced nature of the restaurant and coffee shop also naturally spill outside onto the landscape, taking advantage of the highveld climate.
The Greenbarn’s co-working space includes different working and studying areas to encourage usage beyond business. While there are boardrooms and desk units, there are also informal workspaces with occasional chairs and individual, soundproofed booths to accommodate virtual sessions and private meetings. With the uptake of online learning and hybrid work, the co-working space provides a useful extension to the residential apartments of students, scholars, and working professionals alike.
Energy and electricity
Louvres (a ventilation feature that allows air to pass through it whilst keeping out unwanted elements such as water, dirt and debris) at the top of the Greenbarn work to pull warm air out of the building while circulating cool air back into the space. These remain open 24/7, even when the facility is closed, keeping the space at optimal temperatures without the intervention of air conditioning. The only areas that make use of HVAC systems are the two boardrooms in the co-working space, as they are enclosed for privacy.
Due to the high levels of natural light emanating through the double-volume glazing, fewer light points were needed in the space. Wherever lights have been used, they are motion-activated with low-voltage fittings. Photovoltaic solar panels substitute the use of electricity for the geysers and switch to storing power in battery packs when the geysers are not in use.
The gym has dedicated chutes from the kitchen that lead to appropriately-separated bins outside. These bins are also available to the community to encourage recycling. Up to 30% of the overall project space has been used for the development of pocket parks and walkways connecting Greenlee Greenbarn to its community. Whenever key heritage trees were identified, they were preserved and incorporated into the design. Natural wetlands or existing indigenous features were also conserved when doing the urban design. All finishes in the project, such as paints and tiles, made use of low volatile organic compound (VOC) materials.
The client’s brief was to create bioretention – the process whereby contaminants and sedimentation are removed from stormwater runoff – for the estate’s attenuation ponds (reservoirs). These proved quite the challenge, as they have to retain permanent water while managing the stormwater throughout the area. The capturing of stormwater drainage in the bioretention areas successfully helped to establish an ecologically-functioning water system for flushing and irrigation in close proximity to the lifestyle centre.
Conventional stormwater management systems predominantly focus on quantity management (flow) by collecting runoff and channelling it to the closest watercourse. However, this method has led to the erosion of natural channels and pollution, resulting in environmental degradation. The solutions that are implemented through the Greenbarn’s bioretention attenuation dams, offer an alternative and sustainable approach to designing for water quantity management, water quality treatment, enhanced amenity, and the maintenance of biodiversity.
To that effect, permeable paving has also been used for the lifestyle centre’s hardscaping. This green option of paving allows water to drain through its surface. Lastly, the entire plant palette comprised indigenous species.
Soil and substrates
Most sites in the northern parts of Johannesburg are a challenge, since they are located on Egoli Granite Grassland soil. This type of soil erodes easily; therefore, special precaution needs to be taken to prevent erosion during and after the construction process. Furthermore, the substructures contain large pockets of clay, which must be removed and replaced with viable construction substrate. During the building of Greenlee’s Greenbarn, suitable soils were removed from the park areas for the building-platform substrates, while clay soils were in turn moved to the park areas. This process of ‘switching soils’ was financially beneficial and helped to retain the soils on-site.
Green Star developments should focus on appropriate building principles, such as saving existing trees, utilising soil to the benefit of the project, and making the most of the stormwater on-site. But they also need to be assessed in their entirety before being knighted as sustainable and responsible projects. The extensive paperwork that comes with sustainability should be balanced by the actual implementation of green programmes, ecological construction methods, and the installation of green materials. The Greenlee Greenbarn project successfully applied green principles and guidelines for a future-forward take on environmentally-friendly communal builds.
Boogertman + Partners Architects