Whether you’re planning the build of your new home or you’re a professional working in large-scale development, consider the significant environmental and health benefits of building with responsibly sourced wood as part of the solution to climate change. The reason wood can play a big part in helping tackle climate change is that timber is one of the few natural, 100% renewable building materials.
Responsibly sourced wood is the only renewable building material available; it is naturally grown and removes CO2 from the atmosphere. Wood products then store the carbon that the growing trees have removed from the air (about 50% of the dry weight of wood is carbon).
The production and processing of wood uses much less energy – called embodied energy – than most other building materials, giving wood products a significantly lower carbon footprint. Wood can be used to substitute for materials that require larger amounts of fossil fuels to be produced.
Embodied carbon emissions in the construction sector account for over 23 per cent of total greenhouse gas emissions in New Zealand. The production and processing of timber uses much less energy than most other, more carbon intensive building materials such as steel and concrete. As a general rule, if we can replace a cubic metre of concrete with a cubic metre of timber, about a tonne (1000 kilograms) of CO2 emissions will be avoided.
There are many benefits of using responsibly sourced wood.
CREATING A GREENER FUTURE WITH NEW ZEALAND’S RENEWABLE RESOURCE
When people think of renewables, they tend to think of wind farms or solar panels, but they don’t think of forests or building with wood. Wood is the ultimate renewable resource – so much so that our colleagues in Australia have dubbed it The Ultimate Renewable™. The use of wood helps us to live on nature’s interest, not its capital.
Wood combines performance with wellbeing and environmental advantages. It can play a big part in creating a greener future for all because it is a low carbon option for building; it absorbs carbon during the growth phase, it stores carbon for the long-term, it is renewable and it has a lower embodied energy than many other building materials. As a result, using wood allows us to live a low carbon lifestyle.
FTMA New Zealand believes that choosing timber for building and construction is one of the biggest ways in which we can tackle climate change, creating a greener future for all.
Timber is a natural and renewable resource, which offers both environmental and energy efficiency. It is also an appropriate construction method for the design of environmentally friendly housing in any climate.
Research has found that the global-warming potential of a steel-framed home to be 26% higher than a timber-framed home. The choice of material and design principles has a significant, but previously unrecognised, impact on energy required to construct a building.
For an average 4-bedroom house, research indicates that the use of steel framing releases around 7 times more CO2 in production than a plantation pine frame.
Using wood in construction encourages forestry to expand, thereby increasing the carbon sink effect and reducing the rate at which CO2 builds up in the atmosphere, which in turn, helps tackle climate change.
Choosing timber in design and construction can help tackle climate change in several ways. One of the most important is that wood stores carbon.
Growing trees absorb carbon dioxide from the atmosphere, emit oxygen and store carbon. When the trees are sustainably harvested and used to make wood products, the carbon remains stored in the wood for the life of the product. About 50% of the dry weight of wood is carbon.
Carbon is an elemental building block of all living things on earth. As a forest grows the trees absorb atmospheric carbon dioxide and store it in their leaves, branches and trunks. Approximately half the dry weight of a living tree is carbon, stored for the life of the tree, and retained throughout the timber manufacturing process.
New Zealand’s timber plantations and wood products are all net absorbers of greenhouse gases. The combination of carbon sequestration in growing trees and the long-term carbon storage in wood products represents a significant net sink and store of carbon for New Zealand.
STRONG AND DURABLE
Timber is one of the world’s top performing construction materials. Tried and tested over centuries, its inherent beauty, strength and durability has seen it remain one of the most popular building materials to this day.
Wood is very strong. A comparison with steel and concrete shows that structural timber has a strength to weight ratio 20 per cent higher than structural steel and four to five times higher than non-reinforced concrete in compression.
Timber is also a durable material for both homes and commercial buildings. When properly maintained it can last hundreds of years. Modern timber preservatives enhance natural durability.
Timber has been used for thousands of years and is resistant to heat, frost, corrosion and pollution.
Yes, timber is a combustible material, but it burns in a slow, predictable and measurable way. These factors mean that timber actually performs strongly in fire events, when compared to other materials.
During the event of a fire, a charcoal layer will be formed on the surface of the timber and this layer will contribute to the fire resistance of the material. The charcoal layer insulates the inner core of the timber and it will slow down the heat penetration, keeping the temperate in the unburned material low and enabling the timber to carry its load much longer than steel. The protective charcoal layer created during a fire will also reduce the overall combustion rate of the timber.
This natural self-defence mechanism increases the possibility for a timber structure to survive a fire while maintaining its strength and stability.
TIMBER IS A NATURAL INSULATOR
Timber is naturally an insulating material that creates a barrier between heat and cold. The secret can be found in the many air pockets within its cellular structure, which mean that as an insulator timber is 15 times better than masonry and concrete, 400 times better than steel, and 1,770 times better than aluminium. In addition, lightweight timber framing methods allow easy installation of additional fibre or foil insulation.
As a result of this improved thermal performance, buildings produced using timber, particularly engineered timber such as Cross Laminated Timber (CLT), Glulam and Laminated Veneer Lumber (LVL) require less energy to heat and cool, resulting in reduced energy bills.
In addition, timber is hygroscopic and has the ability to exchange moisture with the surrounding air which provides a buffer against short-term changes in humidity and temperature.
Adapted from an article published by FTMA Australia and reproduced with their kind permission.