Activities | Science | Civil Engineering

Building earth walls - green architecture

Would you live in a house made of earth? This technique of building houses is not new.  Although it is an age-old technique few people are interested in this type of construction.  It is resistant to rain, sunlight and other adverse weather conditions and lasts for years. It is a type of green construction because it is planned so as to take advantage of local resources and reduce environmental impacts resulting from its construction.  Currently it is estimated that 1/3 of the world's population dwells in houses built with earth, material that proves effective in a wide range of climatic conditions from cold and rainy to hot, dry regions.

Houses with earth walls from the time of our grandparents

 Modern houses with earth walls 

 Ancestral houses with earth walls

Arg-e Bam fortress, Iran (source: Wikipedia)

How to build a house with earth walls?  Several techniques can be used to build this type of houses.  Spread all over the world, the technique is known as "taipa" in Portugal, "terra cruda" in Italy, "pisé de terre" in France or "rammed earth" in Anglo-Saxon countries.  This technique provides the same structural performance of a brick wall but has the advantage of being highly environmentally friendly, sustainable, durable and, last but not least, with aesthetic features that are very fashionable in contemporary architecture. Earth is therefore a building material with enormous potential and modernity, suitable for producing quality and comfortable architectural elements.

Materials:

The earth used in these buildings is primarily composed of clay, sand, silt and gravel. The clay and silt are used as binder to confer adhesive strength to the material while the sand and the gravel are used as inert to make the material contract and expand with temperature variations or the presence of water without cracking. The binder-inert balance within the earth material is therefore crucial to its efficiency in constructive terms.

Sand

Clay

Activity instructors: Rogério Sousa and Pedro Costa (Lab.EC)