The training takes just three days

The training takes just three days on eco-materials and a day in construction techniques for house building.

“To date, we have built with this method 306 houses,” said Salazar. “For the coming year, we expect to deliver around 500 houses or more. To build a house, after acquiring the land, we need three people working eight hours a day to build it in four weeks – all under the supervision of a workforce teacher and the supervision of an engineer or architect.

“The houses are designed by architects with the participation of the community or families. They do some workshops and the design conforms to their vision and expectation. In Colombia, there is an earthquake resistance code which is binding in law and provides detailed specifications of the materials, foundations, structure and roof.”

The pre-fabricated building materials are made from recovered waste from a wide variety of sources: ceramic red brick, coarse ash and fly ash, slag from steel, copper slag, porcelain insulators used for electrical power lines, nickel slag, sludge from sugar and alcohol plants and water treatment plants.

“The raw materials we use are industrial solid waste and demolition waste. It costs the industry a lot to throw away this waste,” Salazar said.

He said the biggest obstacle to the new homes is psychological: many people initially “tend to reject at first-hand the technology.”

“When visiting the factory and then visiting the homes – or model homes – they then compare it with a traditional house, and realize that the best eco-homes when finished meet the standards of Colombian earthquake resistance and are also cheaper,” he said.

Compared to using conventional building materials, the eco-materials reduce the cost of a new home. And the company still makes a profit from it!

In Paraguay, Elsa Zaldivar is using recycled plastic, cotton netting, corn husks, and loofah sponges (http://en.wikipedia.org/wiki/Luffa) to make cheap, lightweight construction panels for housing. This has a double benefit: it makes for cheap housing and it is good for the environment.

“That’s very important in Paraguay,” said Zaldivar, “because we’ve already reduced our original forest to less than 10 percent of the national territory.”

Zaldivar got her experience working with people in the impoverished area of Caaguazú, where in the past she helped with the building of toilets and making stoves. She found that involving local people in this work made a huge difference: “They told me: ‘Now we feel like we’re people with dignity.’”

She encourages local women to grow loofah – a plant that once flourished but was being ignored. While the fruit is edible she was more interested in the crusty sponge that is left over when the plant is dried. The women started a cooperative selling loofah sponges, mats and slippers. But there was a lot of waste in the process, with a third not suitable for export. She then came up with the idea to use the loofahs for wall and roof panels for cheap housing.

Along with industrial engineer Pedro Padros, she developed a way to combine loofah with plastic waste. Padros invented a machine to melt the recycled plastic and mix the molten plastic with loofah, vegetable fibres and chopped corn husks. It has produced a building panel that is lighter and easier to move around than lumber or brick. With a grant from the Inter-American Development Bank, design improvements have been made and the cost-per-panel brought down from US $6 per square meter. It is now competitive with the cost of wood panels. The great thing about the panels is that they can be recycled again when they wear out, completing the cycle.

“To have a decent home liberates people,” said Zaldivar.