One of the reasons we became timber suppliers is because we believe in timber as the best building material. Brisbane and the surrounding area are filled with examples of timber’s beauty and strength. But one of the unexpected benefits of timber is that it is by far the most sustainable of all popular building materials.
In an era where climate change has progressed from theory to reality, more and more people are starting to realise that it is our duty to conduct our affairs in an environmentally responsible manner. It is nice for us to know that, at Narangba Timbers, that is exactly what we have been doing since 1979: providing the most environmentally responsible building materials to our friends and neighbours in Brisbane.
No building material is perfect. If nothing else, the energy required to transport the weight of an entire building is going to cause a large carbon footprint. But timber has inherent advantages over other building materials.
We are going to compare timber to other building materials, but first it is necessary to explain the relationship of timber to the carbon cycle.
Timber and the Carbon Cycle
The energy that is used in producing most building materials comes from fossil fuels. The energy that is expended to produce a material is called embodied energy. When using fossil fuels, every energy exchange leaves a carbon footprint.
Therefore, for the most part, the more embodied energy is in a product, the larger the carbon footprint and the more greenhouse gases it has caused to be released into the environment. As you will see, timber’s relationship to the carbon cycle is much more sustainable than that of steel or any manufactured building material.
Trees use the sun’s energy to produce energy and to grow. This process is called photosynthesis. In the process, the tree “inhales” CO2 and “exhales” oxygen. When trees absorb carbon to make woody tissue, the process is called sequestration. Trees absorb carbon from the air and sequester it in the woody tissue.
When a tree produces 1 kg of wood, it “inhales” 1.47 kg of CO2 and “exhales” 1.07 kg of oxygen back into the atmosphere. The carbon which would normally be part of a greenhouse gas is now stored in the tree as wood. The tree also stores nitrogen dioxide and sulphur dioxide. As the tree ages, it loses its capacity to convert CO2 into woody tissue. When any material decays, it releases CO2 back into the atmosphere.
To make a long story short, a plantation or a forest will sequester between one and ten tonnes of carbon per hectare per year. The way to continue this cycle is to chop down mature trees that no longer sequester carbon and plant new ones that do.
Every piece of timber in use continues to store the carbon that it originally sequestered, keeping it from decaying and going back into the environment. Timber buildings storing carbon are called “carbon sinks.”
The opposite of a carbon sink is “embodied energy.” That is basically a measurement of how much carbon was released into the environment to produce a building material. Fossil fuels are used to transport timber and used in many steps of the manufacturing process for steel. The only embodied energy from standard timber comes from the energy used to cut it and transport it.
How Timber Compares to Other Materials
To produce a cubic metre (m3) of timber, 15 kg of carbon is released into the environment, but that timber stores 250 kg of carbon. That means every cubic metre of timber removes 235 kg of carbon from the environment.
Meanwhile, a cubic metre of steel releases 5320 kg of carbon into the environment. A cubic metre of concrete releases 120 kg of carbon into the environment. A cubic metre of aluminium releases a whopping 22,000 kg of carbon into the environment.
Do the Math
After seeing the numbers, is there any doubt that timber is the most sustainable building material? Call (07) 3888 1293 to learn more.