Micro Concrete tiles, mud bricks, pozzolanic cement: EcoSur - Home

Originally published as “The Page” in EcoSouth News, March 1999)

A natural disaster was our introduction to development work…the devastating Guatemalan earthquake of 1976. This country was special for us as I had met my husband there and our automatic reaction to news of the earthquake was “What can we do?”

An assignment with Caritas Switzerland was the outcome and we had the “privilege” of becoming involved in a rather special program of reconstruction. Almost all other organizations totally rejected adobe because it was viewed as the culprit in the loss of more than 20,000 lives.

However, the director of Caritas Switzerland was a very creative and wise person who knew of research done after the 1970 Peruvian earthquake. Through the auspices of the United Nations investigation was carried out to design a low-cost dwelling which would utilize local materials, specifically adobe, but in an earthquake resistant manner. The resultant design was constructed and subjected to intensive tests on the vibrating table. It was this design which we used in the department of Salama in central Guatemala, quite off the beaten track of other major reconstruction projects.

In essence, earthquake resistance was to be ensured through a five-point program which includes: size and shape of adobe, use of half adobes, solid foundation, buttressed corners, concrete ring beam.

In what became a movement of participatory construction, many families were able to build their houses in this manner. An essential starting point was education of local masons in the new techniques, who then went out into villages to work directly with the people, in groups of four or five families.

Some 150 houses were constructed in about thirty villages and, when visited some 15 years later, were found to be in near perfect condition. Serious tremors during that period had caused no damage to the dwellings.

These field experiences in Guatemala with application of the results of the United Nations investigations after the Peruvian earthquake can be interpreted as:

Adequately designed adobe houses can be earthquake resistant.

This introductory experience with disaster resistant construction became something of a “Leitmotiv” for our work when we founded Grupo Sofonias in 1979. Since then we have worked in various post-disaster construction programs, where we sought to educate the local people and introduce different materials and designs which could resist the particular disaster of their area.

In the Caribbean where hurricanes abound, we began to work after Hurricane David (1979) in the area of San Juan de la Maguana in the Dominican Republic. The first housing project in Los Bancos utilized a technology we called “calicanto” in Spanish.

Calicanto is a method whereby large and medium sized rocks are pounded together with cement and lime mortar between reusable wooden or metal shutters. It is a strong material which is ideal when rocks and stones abound in an area. The roofs were made of micro-concrete roofing tiles. Intensive participation of the families resulted in completion of 33 houses in 1984. The houses have withstood many strong storms and hurricanes since then, including the devastating Hurricane George in 1998.

This experience prompted requests from neighboring villages that also wished to build houses. Over the years it has been possible to respond to many of these requests through projects to build some 300 houses and reconstruct about 600.

In an effort to include a variety of technologies and designs, burnt-clay bricks were also utilized, in an innovative manner as vaults, a particularly hurricane-resistant design and material combination. These houses also have withstood the hurricanes and wind storms, including Hurricane George.

As to roofs of micro-concrete, back in 1989 when Hurricane Gilbert tore through Kingston, Jamaica, we were able to confirm that MCR tiles can be hurricane resistant. In the Kingston neighborhood of Trenchtown an old age home we built was the only intact roof, in a sea of flying zinc roofs. In fact, the home served as refuge to much of the neighborhood.

Other experiences with MCR in near-hurricane storms in Nicaragua has confirmed the Trenchtown experience, as had the performance of roofs in Cuba during Hurricanes Lily and George.

Thus, we can say with confidence that micro-concrete roofing tiles are virtually hurricane resistant.

The same can be said of walls made of calicanto or burnt clay-clay bricks

The same applies to burnt-clay brick vaults.

We can say with confidence that we have the experience along with living examples that confirm the viability of various technologies and ecomaterials to withstand natural disasters.

The problem is that there is a tendency for many aid organizations and governments to fall into the trap of over-reaction, to respond to the rehabilitation or reconstruction phase with rapid importation of materials and quick construction solutions. While this is attractive to politicians and to the beneficiaries who like the “gift”, it is not necessarily the way to avoid destruction from future natural calamities. And, it must be remembered that we are talking about areas where particular natural disasters are a recurrent phenomena, somewhat like the avalanches in the Alps.

Our concrete proposal is to consider our experiences and to engage in reconstruction programs that involve non-formal education of builders and community members to become engaged in the construction of their own houses, utilizing ecotechnologies and ecomaterials which have proven to be resistant.

Kathryn Pozak is a founding member and vice-president of Grupo Sofonias, which is a major driving force behind the ecomaterials movement.