Spreading the green word
Cape Town will be hosting the Green Building Council of SA’s third annual convention in September, writes Anna-Marie Smith
THE Green Building Council of SA (GBCSA), a full member of the World Green Building Council and the official Green Star SA accreditation body, sees its convention in Cape Town as a key piece of the agency’s strategy to empower local property professionals with global green tools customised to local conditions.
In so doing it will assist in driving the property industry towards more environmentally sustainable building practices.
The GBCSA’s Green Star points-based rating system currently applies only to office and retail spaces but it will be launching its next tool for multi-unit residential purposes later this month, according to GBCSA CEO Nicola Douglas.
Once the tool becomes available residential building owners and developers will be able to rate their projects and become Green Star SA certified as an endorse- ment of the project’s environmental performance.
Douglas says other countries, such as Australia, which subscribe to the Green Star rating system for commercial and industrial buildings, have government programmes in place for sustainable green building practice of houses, and the US Leadership in Energy and Environmental Design (Leed) has its own rating system that applies to single unit homes.
Douglas says the Green Star rating has provided industry professionals with a useful framework through which to attain green sustainable building practices.
Commenting on the system, Peta Brom, a Green Star SA accredited professional, says: “The most visible green interventions, such as a solar panel roof, seldom have the most intense impact on the building’s overall environmental performance. It is often those design elements that are least visibly green, such as access to nat- ural light, or the installation of displacement ventilation, or a change in the way concrete is mixed (something that would be completely invisible to the common observer) where the greatest environmental performance gains are made.”
Brom says this rating system describes many of the areas of environmental impact that need to be mitigated during construction and operation of buildings.
Industry experts say the architectural design of any home is pivotal to the overall practice of sustainable green building.
Green Star SA accredited architect Louise van Riet says the technological advances of the 21st century should not be ignored, and industry professionals should set priorities to determine effective strategies throughout the process. “Allow your professional team to do assessments on all items of the design: energy efficiency, materials choice and use, site impact, water use and efficiency, building longevity and flexibility.”
She says passive design is the most cost-effective way of incorporating sustainable principles such as keeping heat out instead of cooling a house mechanically, allowing winter sun to warm a house, preventing heat from escaping at night, reducing heating costs, and positioning living areas in the sunny parts and service areas on the cold side.
Van Riet says practical observation results in the smart design of a new house, and huge benefits lie in becoming familiar with the building site through all seasons to determine sun angles, over shadowing from trees, prevailing winds, views, and noise.
Electrical consultants say that homeowners should think and practice green principles, and just one factor such as maximising natural light can make a significant difference in the long term.
Tyrone Wilson, a Green Star SA accredited professional, says WSP Consulting Engineers believes the use of renewable energy should be of priority, as illustrated by projects implementing solar panels for either heating or electricity generation. Wilson says although it is not part of the electrical mandate, little is said about the very effective, natural method of solar lighting.
He says solar light is the best quality light known and is 100% free. Every effort should be made to employ this light source, and one such option is to place skylights on the roofs of houses.
Another priority of sustainable green building is the use of environmentally friendly building materials wherever possible.
Wayne Burton, technical chairman of ClayBrick.org, and a Green Star SA accredited professional, says environmentally friendly bricks, when assessed over their full lifecycle, have a net positive impact on the environment, typically through reduced use of materials in the building, lower energy consumption to achieve indoor thermal comfort, long life of the building, and re-use or recycling if the building is later demolished.
The sustainability of walling solutions would be assessed not only in terms of environmental impact, but also from a social and economic perspective.
Burton says that in SA, thermal performance models have shown that for a standard residential house, using walls with an appropriate combination of thermal capacity and resistance yields an energy cost to achieve indoor thermal comfort, over 30 years that is 25% lower than the same building with lightweight walls.
Bricks are an excellent solution for providing both thermal capacity and resistance in a walling system. Last week saw the government’s support this regard, in Trade and Industry Minister Rob Davies’s publication of amendments to energy efficiency regulations, which would make it compulsory for all new buildings to be designed to a standard that minimised the energy use.
An illustration of an environmentally friendly house designed by architect Louise van Riet.