The Green Building Council of Australia (GBCA) was established in 2002 to assist the property industry in accelerating the focus on environmental design and sustainable development. The Green Star rating scheme was created to help facilitate a shift to greener building practices by promoting sustainable development, green buildings, programs and technologies.
The Green Star rating system is a national, voluntary environmental rating system that evaluates the environmental design and construction of buildings. The star rating system ranges from a best practice level four stars, to a six star 'world leadership' in environmental design and construction.
Credit points are awarded in nine categories that assess the environmental impact of a project's site selection, design, construction and maintenance.
A focus on the categories of Indoor Environmental Quality, Materials and Innovation shows the potential for green star ratings with timber based construction.
Indoor Environmental Quality (IEQ)
IEQ looks at reducing the amount of volatile organic compounds released into the internal atmosphere by building materials, typically through solvents, paints and adhesives. When working with timber, quality water-based polyurethanes, paints and adhesives can provide high performance solutions without significant emissions.
The GBCA also awards points to projects that utilise building materials that offer low or nil formaldehyde emissions. Composite wood products like plywood, particleboard and MDF can all meet such criteria.
The category of materials looks at various ways environmental impact can be minimised by favouring certain materials and building practices. For example, the use of timber can earn a project up to one Green Star 'Timber' credit where 95% of all timber products used are either: re-used timber or post consumer recycled timber; timber certified to the standards of the FSC (Forest Stewardship Council); timber certified to the standards of a scheme endorsed by PEFC (Programme for Endorsement of Forest Certification) such as the standards of the Australian Forest Certification Scheme; or any combination of these. Please note, all Green Star projects that are registered before 1st of January 2010 have the option to use either the new Green Star 'Timber' credit or a previous Green Star 'Sustainable Timber' credit which allows projects to claim two points.
Points are also available for buildings with a design focus on flexibility and adaptability. Timber construction has major benefits for adaptive reuse. Existing timber structures can be resilient when modified and timber can be easily cut, shaped and varied. Where new structures are required, timber places lighter loads on existing structural frames and foundations.
The materials category also awards points to buildings that demonstrate design for disassembly. When screws and bolts are favoured over glues and nails, timber framed buildings can be readily designed for efficient and effective disassembly. One point is available where 50% of the roofing, structural framing and facade cladding are designed for disassembly.
The Green Star rating scheme recognises that there are building initiatives that fall outside the scope of the scheme, but that are nevertheless benefiting the environment. Thus the innovation category offers builders and designers an opportunity to demonstrate new sustainably minded building practices. Innovative tools like carbon calculators demonstrate in a measurable way the significant environmental benefits offered by timber. The number of carbon emissions avoided during construction with timber and the amount of carbon stored in the building over the long term can be calculated to further establish the green credentials of any timber based project.
These are but some of the ways builders and designers can maximise green star energy ratings using wood. Discover more about the different methods available at the WoodSolutions Tutorials.