“Spray-on homes” invented
help the poor, its developers say
Posted December 24, 2004
Courtesy Argonne National Laboratory
and World Science staff
Researchers say they have found a way to build cheap, sturdy homes in one day by spraying a quick-drying ceramic onto flimsy frames. The technology could help the world’s poor, of which the United Nations estimates there are 1.3 billion, they say.
The scientists at Argonne National Laboratory in Argonne, Illinois, and Casa Grande LLC, a Mechanicsville, Virginia-based company, developed the technology. They say they will make it available worldwide it after testing whether the homes are earthquake and hurricane resistant.
The ceramic is called Grancrete. The researchers say that when sprayed onto a crude frame made of Styrofoam, Grancrete dries to form a light, hard surface. This creates a dwelling much better than the flimsy structures in which many poor people dwell.
Grancrete is based on an Argonne-developed material called Ceramicrete, developed in 1996 to encase nuclear waste, according to Argonne’s Explorer Magazine. Ceramicrete thus prevents pollutants from leaking into the environment, the magazine reported. Grancrete also netted its developers an award from R&D Magazine as one of the “100 most technologically significant new products” of 2004.
Casa Grande president Jim Paul told Explorer that his company became involved with the technology because initially, it was was looking for a concrete substitute for American industry. The need arose because concrete erodes in acidic conditions. “But as I traveled in Venezuela, I recognized the demand for cheap housing, and I thought about how to use our material for that,” he told the magazine.
Paul then collaborated with Argonne’s Arun Wagh to create Grancrete.
Grancrete is stronger than concrete, is fire resistant and withstands both tropical and below-freezing temperatures, the developers said; it keeps homes in arid regions cool, and those in frigid regions warm.
To build a home, Grancrete is sprayed onto Styrofoam walls, to which it adheres and dries, according to the developers. The Styrofoam remains in place as an effective insulator, although Wagh suggests simpler walls, such as woven fiber mats, also would work well and further reduce the raw materials required.
Using Grancrete in developing countries has additional advantages, says Wagh.
“When you build houses in these poor villages, the materials you use should be indigenous, and the labor should be indigenous,” he told the magazine. “Every village has soil and ash, and the labor and training requirements are so minimal that two local people can build a house in two days.”
Workers only need two days of training to learn how to operate the machinery, Paul told the publication. Casa Grande typically assembles a team of five people who can start in the morning and create a home that residents can move into that evening, he asserted. The material dries in minutes, he added, whereas concrete can take hours or days.
Grancrete is made from an environmentally friendly mix of locally available chemicals, according to the developers. It consists of sand or sandy soil, ash, magnesium oxide and potassium phosphate, which is a biodegradable element in fertilizer. So even if Grancrete were to decompose, Wagh told the magazine, it would revitalize the soil.
It costs about $6,000 U.S. dollars to build a Grancrete home, Paul told Explorer, several times cheaper than a conventionally built home. The homes are more than four simple walls, the developers added; for less than $10,000 U.S., laborers can produce Grancrete dwellings twice of 800 square feet, twice the size of a typical apartment in Bombay, India.
Wagh’s said he aims to see Grancrete used throughout his native India and the world to produce housing for the poor.
Born in the Indian state of Karnataka, Wagh grew up in a neighborhood where even to this day the homes have walls and ceilings made from knitted mats of palm leaves, and the floors are made of dried cow dung, according to Explorer magazine.
“These homes are regularly subjected to hundreds of inches of monsoon rains and cyclone winds and therefore often have to be repaired or even entirely rebuilt,” Wagh told the publication. “Obviously such conditions can have a great impact on the health, well-being, and longevity of the children and adults living there.”
The spray-on cement now offers hundreds of millions of people such as these the opportunity to have adequate housing and live longer, healthier lives, he told the publication.
Argonne and Casa Grande have extensively tested Grancrete for structural properties, post-application behavior and production costs, the developers said. Their next step will be to test it for earthquake and hurricane resistance, after which they will make the product available worldwide. Wagh hopes the United Nations and other international organizations will subsidize mass-scale production around the world.