While the many benefits of timber products are recognised in a range of ways by rating tools and analysis, there will always be room for improvement.
Some systems take a holistic view of timber, considering aesthetics, social benefits and carbon sequestration, while others focus only on its environmental impact as a material. One thing all the rating systems agree on is the need for appropriate environmental certification to ensure that it is sustainably sourced.
Green Star rewards timber’s sustainability
According to the executive director – market transformation for the Green Building Council of Australia, Jorge Chapa, timber has many advantages in terms of sustainability. The GBCA sees a growing number of projects that use it in both structurally and for decorative applications.
Chapa says timber generally has a smaller footprint when measured by lifecycle assessments than some other materials.
It’s also important to keep the source of the timber in mind. Green Star only recognises timber that has been sourced through a certification system, either the Forestry Stewardship Council or Australian Forestry Standard, which is accredited by the Program for the Endorsement of Forestry Certification.
“A big issue has been the easy availability of illegally sourced timber,” Chapa says.
Certainty and transparency across the supply chain are required to gain materials environmental credits.
Timber can also benefit projects by the increased speed of construction and the warmth it offers to occupants of buildings, Chapa says. However, these are not captured in Green Star, in which the materials credit only accrues points according to its environmental impacts.
The credits also don’t place weight on the extent to which timber has been used – whether it’s just a small percentage of the project’s overall materials, or the majority.
One credit in which timber can generally be of assistance is the environmental site credit, by assessing how much it reduces the amount of waste to landfill.
Materials with an Environmental Product Declaration – such as many timber options – can also gain a product transparency and sustainability credit, making timber a better product for a Green Star project when it’s specified as a composite, in timber for cabinets, for example.
Chapa says that timber’s positives really come to the forefront when a lifecycle assessment is part of the project’s process.
Overall, the more people that are using timber and bringing it to the forefront the better, he says.
Chapa says, architects recognise it has warmth and qualities that are pleasing, and those can’t be replicated by another material.
Timber in the Living Building Challenge and regenerative design
Director of the Thrive Research Hub based at the University of Melbourne, Dr Dominique Hes, says that for a project undertaking the Living Building Challenge, using recycled or FSC-certified timber can result in a building with lower embodied carbon. This reduces the level of offsets a project must undertake to meet the LBC requirement of being zero-carbon.
Timber can also help meet biophilic design requirement, as a naturally sourced material it connects occupants to nature and to the environment.
There is also an aesthetic aspect to wood that addresses the LBC specification that buildings must be beautiful.
Hes says that for the Living Building Challenge, or any regenerative design approach including One Planet Living, the source of timber is “critical”. It needs to be grown, managed and harvested in a way that does not come at the cost of ecosystems.
It also needs to be third-party certified.
Hes says that under a regenerative design approach timber can connect people to places and it can create community benefits if it is also locally grown and sustainability produced.
“It’s about creating connection to, and love of and responsibility for, that material,” Hes says.
One Planet Living also looks to timber
Suzette Jackson, the executive director of Bioregional Australia, which administers, provides training in, and support of the One Planet Living framework in Australia, says there are several of the 10 principles for projects to which timber products correspond.
Under the materials and products principle, the use of 100 per cent reclaimed, reused or certified sustainably-sourced timber would be a positive goal.
Timber also has benefits in terms of “locking up” or sequestering carbon, reducing both the embodied carbon of a building and its lifecycle carbon emissions.
The materials and products principle also has a goal of ensuring products are not toxic over any stage of their lifecycle, and for product selections to result in positive social and environmental outcomes. This includes prioritising sourcing of local materials from regional industry.
Jackson says the One Planet Living Ten principles are not a “checklist”. Rather they are a set of principles for any project, company or local government area to consider in terms of how they proceed toward their goals.
How EPDs promote the case for wood
The cornerstone documents for timber products in rating systems such as Green Star, LEED and Infrastructure Sustainability Council of Australia, are Environmental Product Declarations.
Consultant Stephen Mitchell, co-author of the suite of Australian timber product EPDs that cover hardwood, softwood, medium density fibreboard, plywood and particleboard, says the declarations are a way for manufacturers to provide clear and verified information on the environmental impact of their products.
The driver to develop them, Mitchell says, was their value to the ratings systems, particularly Green Star and ISCA ratings.
In infrastructure projects, he says EPDs are helping drive the use of timber products in urban parks, commercial decking and wharves.
EPDs make specification easier because they included verified data on lifecycle footprint from forest production to end-of-life, as well as information on sources and certifications such as AFS/PEFC and FSC.
Mitchell says that while it is “very early days” for Australian project designers and specifiers to look for EPDs, he expects the local market will follow the l US and European trajectory where the documents have become increasingly important.
“The growth overseas has been exponential because, unlike some product certification systems where you get ratings and winners and losers, EPDs are about laying out the facts so they can be incorporated into decision-making,” Mitchell says.
Mitchell says the industry would like to see people asking for EPDs more often, and the market itself becoming the driver for verified transparency from material producers.
Increasingly companies such as Lendlease and some consultancies are using Life Cycle Assessment software, while many smaller companies are using eTool for project LCAs.
Mitchell says it’s easy for people to make wrong assumptions about aspects of building products and this can result in a flawed and inaccurate LCA. EPDs, however, can be confidently used in the software and tools, as the process of developing them is well-defined, rigorous and third-party verified.
That means the results of an EPD can provide complete confidence in specifying timber in the design of a building, he says.
“Most people want to do the right thing and design and construct a better building.”
- EPDs for popular Australian timber products can be downloaded from the WoodSolutions website (after free registration/login) here.
Lifecycle assessment tools validate the ‘wood is good’ proposition
eToolLCD software is used by some project teams to complete the Materials Life Cycle Impact credit under Green Star. Life cycle design has also been successfully used in projects during the planning approval process to demonstrate a reduction in carbon emissions.
The eTool software draws from an extensive information about materials sourced from the Australasian Life Cycle Inventory database. These include plywood, hardwood, MDF, cross-laminated timber, softwood, particleboard and other commonly specified materials.
Users can choose to use the material data embedded in the eTool software, or enter their own product information from an EPD.
The life cycle analysis accounts for the impacts associated with the material throughout its full life cycle – production and manufacturing, transport to site, construction, maintenance, transport off-site at the end of life and repurposing or disposal methods.
The eTool software includes a range of environmental impact indicators, including; global warming, ozone depletion, eutrophication, acidification, abiotic resource depletion, land use, water footprint and others.
A spokesman for eTool says solid timber has very low impact across most environmental impact indicators, but additives in some engineered products “will change things a little, depending on the product and the specific additives”.
The transport of timber products can also have higher impacts than the production stage and the impact of some timber finishes can also be significant.
There is no “blanket rule” that defines one product as better than another, as it depends on the application.
“Generally however, a mass timber building is going to outperform traditional methods (all else being equal, which it won’t be).”
The primary focus of eTool is to reduce global warming potential in new buildings and in this goal timber products are generally better than comparable products.
“Timber is a natural and renewable resource and intuitively most designers probably think timber is an environmentally friendly option.
“As the dust settles on the LCA science of modelling timber, it turns out the intuitive answer was correct,” said the eTool representative.
Marketing and communications manager at Forest and Wood Products Australia Eileen Newbury says, “Overall an overview of the most commonly used rating options and the information sources that inform them reveal an evolving system.
“However, it is one that still generally demonstrates the environmental advantages of wood and wood products.
“As the use of timber continues to grow, driven by factors such as building code changes relating to mid-rise multi-residential construction and the development of mass timber building systems, we can confidently expect to see ratings systems improve to more accurately encompass and reflect its many benefits,” Ms Newbury says.