Pic 1: Shibam Wadi Hadhramaut in Yemen is made of earthen materials - clay and mud. (Photo credit: Wikimedia Commons)

Earth architecture can be amazingly durable, healthy, environmental friendly, beautiful and strong structure if constructed correctly. Although there are limitations – eg., unsuitable for building high-rises due, earthen structure can be as good as the preferred modern building materials of cement, steel bars.

Earth architecture has also deep roots in all old civilizations, the Middle East, Iran and the cradle of the Sumerian civilization in Iraq (Pic 1). At Shibam in South of Yemen (above pic), there are more than ten stories high of cob buildings.

Why earthen building? Historically, earth has been the most widely known and used building material in construction and probably has been the most important of all building materials (Legget, 1960).

A research done by Middendorf (2001) highlights the many benefits of an earth construction often overlook, underutilized in the developed world. He said recorded cases of the use of earth bricks dates back as “8000 BC” to Mesopotamia civilization. Reports by McHenry (1984) EBAA Australia indicated that, about half of the world’s populations are still living in earth buildings.

Other obvious benefits why build an earth house is it availability. The material is available everywhere and exists in many different compositions. It is the most economical, efficient ways of housing people particularly in developing countries where demand for housing is high.

The technology of traditional earth construction has undergone considerable developments that have enhanced earth’s durability and quality as a construction material for low-cost buildings. Earth structures can be made of completely recyclable materials without polluting the earth. In addition, energy requirement to produce adobe block is only 5 (kWh)/cubic meter, while it is about 1000 (kWh)/ cubic meter for fired brick and 400-500 (kWh)/ cubic meter for concrete (see table 1).

Tabel 1: Energy requirement to produce different building materials (Kleespies, 1991)

Buildings made from earth materials can be a way towards sustainable management of the scarce earth’s resources. They can be put in place using simple machinery and human energy. Earth buildings avoid high-energy costs in the initial manufacturing and construction period, in their use as homes, and eventually in their recycling process.

The following qualities also made earth building attractive:

Sustainability characteristics. These include, the efficient use of finite resources, minimizing pollution and waste and low carbon emissions especially in industrial countries (Little & Morton, 2001). In comparison with other materials, adobe and rammed earth, buildings reflect the embodied energy required for the production and use of various materials. In comparison to brick ad concrete, adobe bricks have the less embodied energy (McHenry, 1984) (Table 1.2).

Adobe blocks do not use organic resources for firing and it does not consume any non-renewable energy. Thus, it has environmental advantages and does not contribute to deforestation. In addition, adobe blocks use very little water, which are essential for people (Little & Morton, 2001).

Economic advantages. It requires no major financial transport costs. It is often comparable in cost with or more economical than other competing technologies. Adobe blocks require only simple production and application tools (moulds, presses, light shuttering and masonry tools, etc.).

By understanding the characteristics of soil we can promote the use of earth as an ecological on-site building material. Many types of soil are suitable for use as building materials. To improve their quality, one needs to identify the characteristics of the soil and its appropriateness for using in building construction. Besides the addition and removal of certain constituents, several tests need to be carried out.

What affect earth building durability and strength? Materials used must be according to all the specifications required. This means that all relevant properties must be checked properly before construction.

The main concerns of earth building is it durability against prolong exposure to water which can weakened the structure. A research by Jefferson indicates that rain penetration results in condensation of water vapour on cool surfaces leading to damp walls. Crawford (1978) said damp walls phenomenon have become more common since the 1920s because of changes in materials use and construction methods.

This certainly can be a cause of worry as the most significant part a typical building and house is the wall. Hence, it makes sense to concentrate work on low-cost walling.

Ruins of 3200 years old earth shelters in Egyptian. It was a mud-brick storage rooms. (Photo credit: Middendorf, 2001)

The other major drawback of earth building is that it needs for continuous maintenance to be stronger and durable, areas which has become the focus of many researches over the years. Most earthen materials are unsuitable for homes of more than two stories as they are usually unable to carry the load of the upper walls.

To withstand the pressure, builder have to make sure the lower walls to be thicker than the upper walls which lead to increase in labor and construction materials cost. What say you?

(Source: Yaser Khaled Abdulrahman Al-Sakkaf, (2009) “Durability properties of stabilized earth blocks”. Unpublished Ph.D Thesis, USM)