Homes built using a technique developed by the engineering research center at the Federal University of Rio de Janeiro cost 30 to 50 percent less than the commercial average and provide better thermal and sound insulation. Interlocking bricks made from local soil and not baked, like traditional bricks, allow 90-percent savings in energy in production, engineer Francisco Casanova, who developed the method, told Tierramérica.

The interlocking pieces, which contain just five to 10 percent cement, are molded with manual or hydraulic presses.

A home can be erected with little or no mortar, according to the model, thus reducing construction time and labor. The Brazilian army and several municipal governments are using the technique to build homes for soldiers and residents. For more information, connect yourself to www.coppe.ufrj.br.