Pros: Very low embodied energy, natural material that can be produced onsite or sourced, relatively inexpensive, recyclable, and fire resistant
Cons: Poor insulator (it’s often necessary to add insulation to mudbrick homes to achieve National Construction Code compliance across most of Australia)
Mudbrick is one of the oldest building materials in the world. This material only requires earth and the energy of the sun to produce, and therefore has very low embodied energy and environmental impact.
Mudbricks are made by mixing earth with water and fillers such as straw, placing it in a mould, and waiting for it to dry.
Despite all the material’s pros, mudbricks are rarely used in modern Australian homes. ‘It is estimated that 30 per cent of the world’s buildings are made of mud, [but] it is overlooked in the west. It is a cheap, sustainable, local and absolutely versatile building material,’ says landscape designer Sam Cox of Sam Cox Landscape.
‘[Using] human energy or labour, rather than industrial manufacturing, is key to their low embodied energy and cost. At an approximate cost of $100 a square metre — and removing the requirement of interior wall linings — it is cost effective.’
Sam used mudbrick to construct his own home in Wattle Glen, Victoria built in the year 2000. ‘We selected this material for several reasons including budget restrictions, local availability, aesthetic appeal and it also adheres to the tradition of mudbrick building in the Eltham area in which we live,’ he says.
‘I was the owner-builder, but as I was working full time, I could only work on it after hours and on weekends with the help of local trades and mates. ‘To speed things along I bought the mudbricks. They were made only a few kilometres away from locally sourced clay and delivered to the site.
‘I laid the bricks myself, rendered them with the traditional recipe of cow dung and local river silt, and painted with a mudbrick colour coat — a product developed by Grimes & Sons in Eltham.
‘It is a material that is easy to build with for an everyday person who is taking on an owner build.’
Sam attributes the declining popularity of mudbrick to modern building standards. ‘Unfortunately, mudbricks have not fared well due to not fitting the assessment process for current energy rating standards for new buildings. The mudbrick industry has since stalled in terms of new builds,’ he says.
To achieve the levels of insulation needed for sustainable house construction and to achieve National Construction Code compliance across most of Australia, it is often necessary to add insulation to mudbrick homes.
‘We are very glad to be living in a mudbrick house. It is a home that is entirely of place and embedded in the landscape… the walls have literally come out of the ground,’ Sam says.
‘I think people who are attracted to this style of home understand it as a way of life, and are not inclined to the overly comfortable, climate-controlled environment of conventional homes. Our mudbrick dwelling functions well enough for us in winter with a single wood heater and no air conditioner is needed in summer.’
Pros: High thermal mass, accessible, usually recyclable, and durable
Cons: High embodied energy, poor insulator, and labour intensive to recycle
Concrete is the most widely used construction material in the world. Its sustainable properties are complex, as it’s a material that provides great thermal mass and is highly durable, but it is high in embodied energy.
The chemical and thermal combustion processes involved in the production of cement are a large source of carbon dioxide (CO2) emissions. Each year, more than 4 billion tonnes of cement are produced, accounting for around 8 per cent of global CO2 emissions.
‘It has high levels of embodied energy due to the mining and processing of natural resources to manufacturing, transport and product delivery,’ says Nick Walters of Altereco Design.
‘This is still low compared to MDF or glass, and very low compared to plastics, rubber, aluminium, steel and copper.
‘Concrete companies are also offering lower-carbon intensity cement mixes, which definitely make the material less carbon intensive — but still far from eradicating its intensity.’
While concrete is technically recyclable, it can be difficult to process, and currently accounts for a huge portion of construction waste.