Corobrik contributes to Green Star rating for the new Sisonke District Office in Ixopo, KwaZulu-Natal.
The KwaZulu-Natal Department of Public Works’ new Sisonke District Office in Ixopo is the first provincial government building to achieve a five-star office V1 design rating from the Green Building Council of South Africa (GBCSA).
The Sisonke District Office is the first of a four-phase project and consists of two single-storey buildings – an office block and conjoined maintenance block – as well as a separate garage block. The total floor area measures 858m2 – the commercial office area is 550m2, while the car park is 193m2.
Locally sourced materials
Corobrik bricks gave designers an opportunity to achieve sustainable, quality buildings with due sensitivity to key environmental imperatives. Architect Steve Kinsler specified the use of Burnt Apricot face bricks, as well as Corobrik concrete pavers and retaining blocks for this project. “Important considerations were that all building materials had to be sourced locally. The closest factory to the site was our Eston brick factory, from which the Burnt Apricot face bricks were procured and supplied,” explained Mike Ingram, Corobrik’s director of sales for KwaZulu-Natal and Border.
Kinsler pointed out that the Green Star rating system awards points for materials sourced from within either a 50km radius of the site or, failing that, a 400km radius. “Burnt Apricot Satin face bricks, NFX and NFP stock bricks were sourced from the Eston brick factory, which is located 70km from the site.”
Eco-friendly and sustainable features predominated when it came to both practical features and aesthetics. One of the main stipulations was minimising energy usage. “The office building has a long and narrow form with the north orientation increasing the solar gain in winter and reducing it in summer,” Kinsler said.
At the time of purchase, the site was covered with a mismanaged alien tree plantation that had become infested with alien invasive weeds. The new office block has an extensive roof garden that is home to nearly 100 indigenous plant species.
The insulation properties of the building were optimised through the roof garden over the main office spaces and the installation of insulation in the cavities of the brick external walls, below the floors and in the roof.
All external windows are double-glazed. While natural daylight minimises the amount of artificial light needed, natural air flow is maximised. This, in turn, removes the need for mechanical air-conditioning. Solar water geysers provide hot water, while lighting systems use high-efficiency lights that are fitted with motion sensors.
Ventilation and light
The offices are naturally ventilated and there are no ducts for air supply or cooling. A heat-pump circulates warm water through the floors in order to meet winter space-heating requirements. Due to the long, narrow form of the building, 85% of the interior spaces are naturally lit, while motion sensors automatically switch lights off when no one is in the room.
Water-wise Potable water consumption is reduced through water-efficient sanitary fixtures and rainwater is harvested for washing cars and flushing toilets. This reduces the run-off from hard surfaces during storms.
Cycling facilities are provided for building users and visitors, while preferential parking is reserved for fuel-efficient cars and motorcycles.
Rehabilitating the natural environment
The remainder of the site is being returned to its endemic Natal Mistbelt Grassland habitat. All plants are dry-land, indigenous species that require no irrigation.
Built to last
Enhancing the natural environment
Ingram pointed out that the use of clay bricks further enhanced the holistic environmental value of the project. “Within the environmental sustainability equation, Corobrik offers clay bricks with embodied energy values in line with international best practice for the technologies employed and with thermal performance properties that support superior thermal comfort and the lowest operational energy usage,” he noted.
Many generic factors underpin clay bricks’ environmental integrity, namely durability and longevity, reusability and recyclability, inertness that ensures no release of VOCs or toxic fumes to impinge on air quality, incombustibility, natural sound-insulation qualities, inorganic qualities that do not provide a food source for mould, maintenance-free qualities that incur no future carbon debt, and earthy colours and textures that sit unobtrusively in natural environments.
According to Ingram, research has substantiated these intrinsic qualities. “Lifecycle assessment has established that irrespective of house construction type, embodied energy comprises no more than 10% of the total energy consumed over a 50-year lifecycle. Heating and cooling energy comprises up to 40% of the total energy consumed,” he noted.
Significant empirical and thermal modeling studies into walling envelopes’ thermal performance in houses confirm that thermal mass inherent in clay-brick walling is a critical thermal performance property. Importantly, this is critical when it comes to achieving thermal comfort and the lowest heating and cooling energy usage necessary for lowering South Africa’s carbon footprint.
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