Proposals to improve the sustainability performance of residential buildings as part of a new Queensland Building Plan are ignoring the biggest carbon win, according to chief executive of Timber Queensland Mick Stephens.
His association has called on the government to ensure that sustainable materials are made part of the policy, and that embodied energy impacts are given equal weighting to operational energy efficiency.
“Historically there has been a strong emphasis on energy efficiency,” Mr Stephens told The Fifth Estate.
A lot of that low hanging fruit has now been dealt with, he said.
That means the building sector is “approaching the law of diminishing returns” in terms of making buildings more energy efficient.
“The elephant in the room is materials and structure.”
When the embodied carbon footprint of these is addressed, the gains become “more significant” in terms of reducing carbon emissions from construction and also sequestering carbon.
“Research has shown that the choice of building material can represent up to 50 per cent of the total greenhouse gas emissions from a new house in Brisbane over a 50-year cycle.”
Mr Stephens said that compared with concrete, aluminium and steel, wood products had very low embodied energy and required much lower fossil fuel energy inputs for their production.
“Concrete’s embodied energy impacts can be more than six times higher than timber,” he said. This is because trees use the sun and photosynthesis to produce timber and remove carbon emissions from the atmosphere in the same process.
“Switching to a greater use of timber in buildings can generate significant carbon benefits for the state.”
If half of all new residential buildings constructed annually were “timber maximised”, the result would be a saving of 600,000 tonnes of carbon emissions a year.
The association has recommended the state government adopt a formal Wood Encouragement Policy (WEP) that aligns with the building plan. Already two local councils, Gympie and Fraser Coast, adopted WEPs in January 2017.
Councils in other states including Kyogle and Wellington in NSW and Latrobe in Victoria have also done so, and internationally France, New Zealand, Canada, Finland and the Netherlands have adopted WEPs as part of the procurement process to capture the potential carbon abatement benefits of the material.
Under a WEP, the full consideration of timber as a preferred choice of sustainable material is required where fit-for-purpose.
Mr Stephens said timber had dual benefits: environmental credentials and economic contribution to the state.
Growing demand would also increase investment in both forests and their products.
This would have a major benefit in terms of carbon sequestration. TQ’s submission stated that the planting of 10,000 hectares a year of new softwood plantation over the next decade would capture and store an additional 15 million tonnes of carbon emissions.
There is also a clear economic benefit to be gained. Currently, the industry generates around 10,000 direct jobs and has a $3.1 billion gross annual value.
It is a diverse industry, producing plantation pine products including structural timbers, framing, cross laminated timber and laminates, as well as native hardwoods and native cypress, a naturally termite-resistant timber.
“Given the diversity of the industry, timber can meet a whole range of applications,” Mr Stephens said.
Another benefit of sourcing timber products from within the state’s own industry is the building supply chain is more immediate and it is easier to have transparency, he said.
“That means the paperwork and compliance needs are also lower.”
Tackling non-conforming products
The proposals for the Queensland Building Plan have highlighted the issue of non-conforming products, and this is something the association has addressed in its submission.
All of the state-owned plantations or native forests are certified either under the Australian Forestry Standard or Forest Stewardship Council standard.
The private native forests are not all certified, but have to abide by a mandatory code to ensure sustainability.
“The industry is highly regulated.”
Mr Stephens said the issue for private forests was the cost of certification. Most are small land owners, so the industry association is looking to overseas examples such as Sweden, where a number of private forests obtain certification at a cost-effective price under a group certification scheme.
Another benefit of timbers in the tropical Queensland climate is that they are lower on thermal mass, so are good for keeping homes cool, he said.
It is also a material associated with the traditional “Queenslander” style of residential architecture. These homes also tick other sustainability boxes, with elevated structures for coolness and flood resilience, good ventilation and open areas.
“The [local] industry is familiar with using timber.”
Mr Stephens said that in some of the sustainability codes and practices being applied, the emphasis on energy-efficiency means projects are “missing the benefits of materials” to address thermal performance and energy use.
“The benefits of energy efficiency [in design] can be lost.”
If the aim of sustainability codes and practices is to tackle climate change, using wood and timber is one of the most effective things we can do, Mr Stephens said.
He said the Green Building Council of Australia was already starting to move in that direction, with its recent announcement of a credit pathway for massive timbers in construction. This was something the association highlighted in its submission.
“I am greatly encouraged by this progress,” Mr Stephens said.
“Designers and architects are also starting to recognise the benefits of wood.”
Submissions on the Queensland Building Plan close Wednesday 15 March 2017, however online surveys are still being undertaken until the end of March 2017.
- Read the proposals and have your say here