22 October 2012 – Pretoria Portland Cement (PPC) is providing its products for anet zero energy house project in the developing Waterfall Estate, Johannesburg. The net zero energy house, managed by SDR group, is designed to collect as much energy from renewable sources as it consumes. PPC is supplying all the cement and aggregates.
A substantial portion of the house will be constructed with concrete, which is an economic material and ideal for eco-efficient construction. The primary ingredients of concrete are aggregates, sand and water, which account for the bulk of the mix, while cement only makes up 10% – 15% of the mixture. However, the greatest factor that determines the green element of concrete is the composition and strength of cement.
PPC’s research and development specialist, Alta Walker, explains, “Using premium performance cement in conjunction with good quality aggregates ensures the concrete is durable and produced with a lower carbon footprint. The 15% more concrete with our improved strength products contributes to the reduction in the effective carbon footprint.”
The thermal mass properties of concrete contributes to effective indoor environmental benefits, moderating high indoor temperature swings and effectively reducing reliance on mechanical heating, ventilating and cooling systems, further reducing the home’s dependency on external energy.
Another benefit of building with concrete is its low to negligible levels of volatile organic compounds (VOC), which means reduced emissions into the air, soil and water.
“The aim of sustainable construction is for the creation and responsible management of a healthy built environment based on resource efficient and ecological principles,” Walker says.
The 650 m2 net zero energy home features other sustainable elements such as renewable energy supply via a solar photo voltaic array, enhanced day-lighting and passive systems for heating and cooling such as evaporative cooling tower, hydronic underfloor heating, as well as low energy LED lighting and high efficiency appliances.
Sean Rodrigues, architect and CEO at SDR group says, “Concrete is an integral part of our building approach in creating net zero energy homes and communities, playing an important role in our energy reduction strategies, through thermal performance. In addition exposed concrete walls and floors are poured and finished very quickly, cutting construction time, whilst maintaining a high aesthetic quality and the low VOC nature of the material, delivering a healthier indoor environment.”
PPC has long been committed to providing energy and resource efficient products with the focus not only on carbon and energy management, but reducing the company’s overall environmental footprint through sound environmental management practices. During October 2011, a PPC group energy policy was approved by company CEO, Paul Stuiver, which reinforced PPC’s focus on minimising its impact by formally targeting a 10% improvement in electrical energy efficiency, a 5% improvement in thermal energy efficiency and a further 5% reduction in its specific carbon footprint, by 2017.