When we think about sandbags, we think of flood prevention. But did you know that you can use them to build your house? We like to build houses that work in harmony with nature and hence, sand, earth, straw and other natural products are used to build what are referred to as Earth Homes.
Earth Building is the practice of building using unfired earth material. Earth is used to construct walls, floors, roofs and even furniture, fireplaces and ovens. It is a building technology with an 11,000-year-old history and tradition, which is utilised worldwide. Today it is estimated that between one third to one half of the world’s population are housed in earth homes.
The common feature in all earth building techniques is that the earth material is subsoil that is composed of clay, silt, and sand where clay is the binder or cementing ingredient and that the drying process is through the evaporative effect of sun drying.
The methods and techniques used are as varied as the people of the earth, the resources available to them and the climates in which they are used.
There are at least 12 methods of earth building used and these can be further divided into a total of at least 18 techniques.
Perhaps the best known methods are:
Earth Brick (Mudbrick/Adobe)
Mud brick is the most popular name used in Australia to describe bricks made from various compositions of soil and dried at air temperature in the brick production stage.
There are almost as many ways of making mud bricks as there are mud-brick makers. One major distinction, however, is the consistency and water content of the material at the time of forming into bricks. With puddled mud bricks, the moisture content is quite high and the texture is that of mud or dough. With pressed mud bricks the moisture content is lower and the consistency is that of damp soil.
Rammed Earth (Pise)
Rammed earth is damp or moist earth, with or without any additive, that is rammed (tamped ) in place between temporary moveable formwork. It is a solid masonry wall which does not have, and does not need, any cavity.
Australia leads the world in modern rammed earth construction, both in quality and volume of projects built.
Appropriate, Renewable, Sustainable Technology
Earth building is an appropriate, renewable, sustainable technology. We believe it is exactly what the world needs today to provide safe, durable, comfortable and desirable homes. Those who have owned or lived in an earth home would know and appreciate this.
Earth building is appropriate technology because it is simple and available to everyone – poor or rich alike. The material is durable (100 – 400 yrs plus proven in Australia, Europe, England, Middle East) offering longevity rivalling modern western housing (25-50 yrs, Australia). It is adaptable, being used for footings, floors, walls and roofs utilising many techniques.
It is flexible because it can be moulded and shaped when wet, rammed and pressed when moist but hardens in the sun so that it is durable.
It can be carved, shaved and sawn when dry. The surface when wetted can be reworked to a polished finish if required. It can be used to create buildings of any shape or style. It is raw and natural and has low embodied energy and can be used to achieve thermal mass and insulation by adjusting its density and thickness. The material is non toxic, non allergenic, controls humidity, is fire, rot and termite proof and therefore earth can be used to create safe and healthy buildings. Earth offers great sound isolation.
Many designs and methods of utilising earth have been developed around the world to suit various climates and cultures. Earth is a very attractive building material, in harmony with the local environment from which the material was found and especially when used with other locally sourced, natural building materials. The aesthetic beauty and also comfort can be enhanced if local vernacular building styles are utilised.
Local indigenous or traditional building styles often use climate responsive designs and are appropriate in relation to other environmental factors like weather and natural hazards.
Earth Building is renewable technology because the material is often simply borrowed from the earth for the life of the building and can be reused and recycled indefinitely as a building material or returned to the earth. The energy used to dry the earth into bricks or monolithic walls, floors or roofs is solar energy because in earth building the earth is sun dried through evaporation. The thermal mass of earth can be used to store both warmth and coolth, balancing diurnal fluctuations in temperature in all seasons. Earth building therefore uses basic solar technology to produce the building and maintain comfort.
Earth building is sustainable technology. The use of raw unfired earth as a building material dates back to 9000BC and today it houses one third to one half of the world’s people. The material is abundant and widespread, uses very little energy in the entire process from raw earth to building, is durable, and its properties make it an excellent choice for climate responsive buildings. These buildings achieve thermal comfort and a degree of free running through consideration and selection of the appropriate method design. As previously stated, earth can be easily recycled and reused. Its sustainability credentials outshine any modern material in any life cycle analysis; from the embodied energy in creating the building through the reduced energy used in its long life, in maintenance, heating and cooling, to demolition and reuse.
Earth is possibly the ultimate Green Building material.
How do we meet the challenges of comfortable safe buildings whilst reducing the energy used in construction, heating and cooling of buildings, improve indoor air quality and longevity of buildings and reduce toxic waste to landfill?
How do we raise the living standards of poorer people and maintain our’s without depleting resources, increased environmental degradation and loss of biodiversity? How do we future proof our buildings against spiralling energy costs and shortages?
How do we build homes, enjoy our existing lifestyle and reduce our need for fossil fuelled energy and GHG emissions dramatically?
It is a technology that is ancient yet still most relevant.