Timber to the Rescue

“The biggest personal financial investment the average Aussie makes is their home — the biggest climate change/carbon emission benefit can also be the home.”

As much as I prefer to write ‘my own thing’ in my Bulletin articles, there are times when I need input from those way better qualified than myself. The subject of Greenhouse Gas Emissions and the role timber can play in helping reduce levels in the shelter industry is one of those.

Alastair Woodard is a Structural Engineer with a PHD in Timber Engineering. Above all he understands the sustainability of wood, its renewable and carbon sequestering ability. I asked him to present a paper that looks at timber’s role in Australia’s increased housing needs and at the same time cutting Greenhouse Gas Emissions – is it possible?

Alastair leads our industry in all matters relating to timber and particularly its use as the premier building material.

“The Australian Federal Government has committed to reducing greenhouse gas emissions by 43% below 2005 levels by 2030 under the 2015 Paris Agreement and is now developing the Net Zero 2050 Plan which will establish the pathways for transition to a Net Zero economy including in the built environment. 

The Government has also proposed a major residential building program under the 2022 National Housing Accord, setting an aspirational target to deliver 1.2 million new, well-located homes over the next 5 years; State Governments are also committed to these targets and are implementing respective policies, plans, and programs with this aim.

Interestingly, these two policy aspirations are intrinsically linked, because ‘more building’, means ‘more greenhouse emissions’ — but it is also acknowledged that reducing emissions in the built environment will be fundamental in Australia reaching its Net Zero target, so we need to build differently with agreed and focussed net-zero goals. 

1.2M new homes over 5 years means 240,000 new dwellings built annually – which effectively is an additional 80k dwellings a year nationally – this will require a mix of new detached dwellings and apartment units.  How these new dwellings are constructed, and the materials used, will be extremely important in regards their climate change impact.

Wood products can be used as the primary structural / construction material in many of these new dwellings to enable a reduction in greenhouse gas emission impacts:

• lightweight framing for detached dwellings and low rise buildings
• mass timber solutions for mid-rise apartment buildings.

The critical emission sources in the building and construction sector are the burning of fossil fuels for energy, and use of high CO₂ emitting materials and processes – effectively the emissions embodied in the products.

Embodied emissions released before the building is occupied (upfront emissions) are expected, without intervention, to go from 16% to 85% of the built environment’s total carbon footprint by 2050 as more renewable energy comes online.   So, it is important to understand the embodied emission impacts in the production of the products that you use – cement, concrete, steel, aluminium, timber etc.

A key tenet of all built environment related embodied carbon policies and voluntary initiatives is the concept of increasing the use of low embodied carbon emission building materials and low emission construction practices.

Forests and wood products are a natural and renewable resource which can help to address the building product greenhouse gas emission issue, as timber products,

• store carbon during growth.
• uniquely lock away the carbon for the life of the product,
• have comparatively low emissions in manufacture relative to other alternative more emission-intensive materials such as steel, concrete and aluminium, and
• can deliver high on-site productivity and low emission off-site prefabrication construction system efficiencies.

To reduce building product related greenhouse gas emissions, in addition to your voluntary actions, in reality the Government needs to also mandate policies that

• incentivise the uptake of low embodied emissions building materials and construction practices
• endorse an agreed national/state framework to measure, verify and compare embodied emissions in new building projects – current desire from the national Building Minister is to implement this in NCC 2028
• maximise structural timber construction product use, particularly in social and affordable housing applications (lightweight framing and mass timber)
• require social housing to be the highest quality of sustainable residential construction – timber-framed-passive house construction – thereby significantly minimising the future energy use costs for the social housing residents
• improve ‘home resilience’ by requiring raised timber floor construction (particularly for flood prone areas or on significantly sloping sites)
• support and incentivise offsite construction – particularly high on-site productivity, off-site prefabricated ‘Elemental Solutions’ through Australia’s extensive existing frame and truss sector network for homes and low-rise construction projects, and off-site manufactured mass timber systems for mid-rise apartment construction.

Timber’s true total value in its use in the built environment comes from:

• the huge environmental, social and economic benefits in growing the forests locally,
• the atmospheric biogenic carbon that it stores,
• its constructability and suitability as a high strength-to-weight ratio structural material, combined intrinsically with
• its aesthetic beauty and biophilic benefits as a natural material.

The true value of forest and wood products needs to be clearly, and unambiguously, recognised and fostered by Governments, the building industry, and the community, for the significant social, economic, and environmental – ecological and stored carbon – benefits they provide.”

You as a builder and a client of Bowens can make a difference.  Be informed and conscious of your material choice and its impact on the environment in which we live.  Make a positive decision which will benefit you, your kids and all future generations – insist on using more timber wherever possible, it ticks all the boxes and covers everything required for our future built environment.

“You as a builder and a client of Bowens can make a difference.”