Building with Earth - Brazil's Most Popular Raw Earth Building Techniques and the Opinion of Experienced Builders

Abstract

Earth building construction techniques bring the promise of being environmentally friendly, thermally comfortable, easy to maintain and aesthetically interesting. Therefore, the ideae is beginning to spread in Brazil, being divulgated mainly by institutes and groups involved with Permaculture studies. The possibility of building sustainably and independently has contributed to the increasing number of people embracing the cause and starting constructing with earth and other raw materials. But what are their opinions after the end of the process? This work brings a review on some of the most popular earth building techniques in the Brazilian Federal District and state of Santa Catarina (superadobe, hyperadobe, rammed earth, cob, stucco, and double stucco filled with plastic bottles), as well as interviews with builders and users of the resulting houses. The research showed that the houses were built mostly by the owners themselves, with only a few having relied on professional help at some point. The drawbacks appointed were the lack of qualified professionals well-acquainted with these building techniques, the difficulties in managing large groups of voluntary builders and the high physical effort demanded by some of the techniques. Actually, many houses were composed by more than one technique. Some were built using a different technique to each wall. Superadobe was the preferred one at first, however most builders decided to change to other techniques for the practicability or just for the sake of experimenting. The experimenting of different techniques was more frequent in the cases when the house was the first construction of the builder (s). Unfortunately, the lack of experience had serious consequences, for it was noticed that some buildings showed construction pathologies, such as pending walls and peeling plasters. Nonetheless, most of the users declared to be satisfied and considered earth building a good investment. In fact, the houses had good thermal performance, used low impact materials and had a medium cost of approximately BRL 310.00 per square meter. A considerably lower price than the average BRL 670.00 per square meter, estimated by Brazilian authorities for the same locations and building patterns at the time of the constructions.