Sustainability in Construction

We have all witnessed or been affected by the devastating effects of rising levels of CO2 on the environment with extreme weather conditions and flooding throughout the world in recent years.  It is undeniable that, if we do not take drastic action now sea levels will rise and plant and animal species will be lost.  Our current lifestyle has been described as unsustainable – but what is the definition of sustainability?

Using the Earth’s resources without harming the environment.  Sustainability takes into account present day needs with those of the future.

‘Development which meets the needs of the present without compromising the ability of future generations to meet their own needs’ (World Commission on Environment and Development, Our Common Future)

Wood can play a major role in combating climate change – by absorbing carbon dioxide in the atmosphere as one cubic metre of forest absorbs one tonne of CO2 and by reducing greenhouse gas emissions by substituting for fossil fuel intensive products.

Life Cycle Assessment is a technique which assesses the environmental impacts of a building component right the way through its life.  Assessment tools are being developed to assist designers, clients, specifiers and developers to achieve sustainable strategies for housing and commercial building.  There are three broad areas to consider when assessing the relative CO2 impact in the use of various building materials:

• The energy used in the production of the material
• The ability of the product to save energy during the use of the building
• The recycling and final disposal of the materials or product

Timber is the most sustainable building material as it is a natural product and it is renewable as we can grow more. The timber that we use needs to be sourced from well managed forests. Sustainable forestry management involves regeneration which is the process of harvesting and replanting. Forests act as carbon sinks, absorbing carbon dioxide and giving out oxygen, helping to reduce the effects of global warming. One cubic metre of wood absorbs one tonne of CO2.  As a tree reaches maturity it has a diminishing ability to absorb carbon dioxide as it stores all the CO2 absorbed during its lifetime.  These older trees need to be felled and replaced with younger trees that have a greater capacity to absorb greenhouse gases.  This improves the health of the forest and provides mature timber for a variety of purposes. 

The production and processing of timber makes it one of the most energy efficient materials available. Wood is considered to have 'low embodied energy' as it requires little energy to manufacture as it grows naturally, it has low lifetime energy use as its thermal qualities mean that less energy is used to heat buildings and, at the end of its life, stored energy is released through combustion.

Building a house in timber instead of brick reduces carbon emissions by 10 tonnes.

TEN GOOD REASONS TO CHOOSE WOOD

1. Wood is a good thermal insulator – reduces heating costs.  In fact wood has the best thermal insulation properties of any mainstream building material.
2. Forests contain diverse forms of life.  Over 90% of the wood (hardwood and softwood) we use is sourced from European forests and these forests are growing by 661,000 ha every year – an area greater than three football pitches every hour of the day and night.  Greater use of wood products will stimulate further the expansion of Europe’s forests
3. Timber products are biodegradable.  When timber products finally come to the end of their useful life they can be disposed of by being burned or by rotting naturally.
4. Waste products can be recycled into other materials such as particle boards and MDF or used for heating, therefore reducing the need to use other fossil fuels
5. Growing trees absorb emissions (forests are referred to as carbon sinks).  Sustainably managed forests are run with respect for the planet, people and prosperity.  Great care is taken with the choice and mix of species, harvesting at maturity, natural regrowth and planting, respecting the ecosystems on which local flora and fauna depend and the way of life of people who depend on the forest.
6. Wood is carbon neutral. The substitution of wood for other materials can result in reduced CO2 emissions as the carbon dioxide stored by the forest and in the timber product outweighs any carbon dioxide created during the production of the product.  Each tonne of timber used instead of other building materials (like steel, brick or concrete block) saves around a tonne of carbon dioxide.
7. Wooden joinery can be renovated and repaired.
8. Wood is durable.  A good quality wooden product should, with care and maintenance, last a lifetime.  Many Victorian houses still have their original wooden windows, doors and floors.
9. Wood is naturally beautiful and adds character and warmth.  It usually adds value too.
10. Wood is highly versatile and can be moulded into many different designs and forms.

References:  www.woodforgood.com 
www.bwf.org.uk
www.timbmet.com
www.internationaltimber.com