In South Africa, designers are using surprising materials to house localsEvery year, Cape Town's Design Indaba conference draws together high-profile architects from around the world to muse about the power of contemporary design. In 2007, Indaba's organizers decided to use that concentrated creative energy to address a problem in their own backyard: the thousands of impoverished people living in makeshift shacks in South Africa's townships. Looking to create low-cost houses that could serve as models for the future, they launched the 10x10 Housing Project, which paired 10 leading international architects with 10 local architects, and tasked each team with developing an appealing house that could be built for about $7,000.Luyanda Mpahlwa, a partner in the firm MMA, and his team decided to build theirs with an unlikely but abundant source: sand. "African industry usually uses bricks and mortar, or clay brick, or concrete block, which is more expensive," says Mpahlwa. "As architects and professionals, we should be leading the search for different ways of building. Not everyone can afford the normally available material."It was a wise design decision. Not only is MMA's house the sole design to be realized so far, but sponsors have funded the construction of 10 individual units for 10 families, rather than the originally planned single residence. The project also won the inaugural Curry Stone Design Prize, an annual $100,000 award for humanitarian design, in September. The houses are now nearly complete in Freedom Park, a community on the outskirts of Cape Town that was previously a warren of shacks.Starting from a shell of EcoBeam timber framing, which uses a minimal amount of wood strengthened with zigzagging steel bars, the houses use row upon row of stuffed nylon sandbags to give the structure heft and permanence. Using sandbags for walls has a number of advantages. It's a readily available material, and it has good thermal qualities, which protects from the heat. Sand is also very sturdy when packed, and is good at dampening sound-an important consideration for communities where houses are clustered tightly together. But perhaps most importantly, MMA has designed a house that "can be built by hand by anybody," says Mpahlwa. The houses in Freedom Park are constructed with volunteer help from local women.After all the bags are stacked, most of the exterior walls are wrapped with a wire mesh that gets coated with a thin layer of plaster, while a few sections are covered with wood or metal to achieve a desired look. The modern design of the 580-square-foot house offers something distinctly different for the area, with two floors of living space and a balcony that provides the basis for future expansion. "It's not high-science in terms of design," says Mpahlwa. "But for the area, it's very different, and for a family that has never had a house, it is spectacular."The 10 houses are being given away for free to families who were selected via lottery, and MMA has ambitions to expand the project beyond Freedom Park. "This is a pilot project," that could be a model for other areas, says Mpahlwa. "We wanted to find something that could be a low-cost housing solution for the future."