For many years Elsa Zaldívar has helped rural women in Paraguay rediscover the benefits of loofah, a cucumber-like vegetable that when dried becomes a scratchy sponge. Zaldívar worked with a group of poor women to produce organic, blemish-free sponges on trellises in their back yards, then sell the sponges as abrasive skin scrubbers, as well as use them to manufacture mats, slippers, insoles and a variety of other products that are exported to markets as far away as Europe. The women’s income soared and Zaldívar, a development specialist, started wondering what else they could do with the plant.
In 2008, she won a Rolex Award for an ambitious plan to mix imperfect loofah sponges and loofah waste with recycled plastic and other natural materials to produce strong, lightweight panels that could be used to construct low-cost houses. Paraguay faces a critical housing shortage, and mixing renewable and recycled materials seemed a promising path toward providing dignified housing for the poor.
The concept attracted attention from around the world. Television crews from Europe and Asia came to document Zaldívar’s construction of prototype houses, which included doors and windows made of the panels. Samples of the loofah panels were exhibited at the Smithsonian’s Cooper-Hewitt National Design Museum in New York.
Yet Zaldívar’s project encountered problems. A machine designed to produce large panels was plagued by glitches. The price of recyclable plastic waste soared with the cost of petroleum. And in field tests the panels proved susceptible to discoloration from mould. Zaldívar tracked that problem to the inclusion of jute, which wicked water from the outside to the inside surface of the walls. The application of an additional sealer would have resolved the issue, but that would have driven the price too high for widespread use by very poor families.
Zaldívar remains committed to finding a way to fabricate low-cost housing panels and she is testing new combinations of natural products. Yet she has also experimented with other uses for loofah. By shredding the loofah sponge and mixing it with cassava scraps that are either thrown away or fed to animals, she has created a plaster that can be applied to existing houses. The results have been encouraging.
“I was looking for a way to use the sponge that would depend less on technology, and I arrived at a simple solution. The plaster improves the appearance of the house and provides substantial thermal and acoustic insulation for houses already built from lumber or for new ones constructed with bamboo. We started doing this in 2008 and so far it’s working well,” she said.
“It adheres easily to the walls and protects them from insects. It fills the gaps between boards, which blocks wind and dust from entering the house. Above all, it’s something that people can do without asking for help from others. You just need loofah and cassava, two products which rural residents can produce themselves.”
Even if homeowners have to buy the materials, Zaldívar estimates the cost at only about US$0.50 per square metre. No special skills or tools are needed to mix the ingredients on site or apply them to walls. The plaster can be applied to both the inside and outside of walls, and can be painted afterward.
When applied to the walls of even the poorest houses, which are often constructed of mismatched scraps of lumber, Zaldívar says the end result looks the same as if the walls were made of bricks plastered over in the traditional manner. She says that helps reduce the stigma of poverty.
Zaldívar is director of Base Educación, Communicación, and Tecnología Alternativa[Grassroots Education, Communication and Alternative Technology], which arranged for the plaster to be applied several homes in a government-financed housing project. Initial reviews are positive.
Dominga Alegre de Almada, a farmer in the small town of Repatriación, has for years worked hard growing loofah and selling cheese so she can send her children to university. She says she was doubtful of Zaldívar’s concoction at first, but after witnessing the experience of others, began applying it to her own walls. “I have long dreamed of having a beautiful house, but I’m poor, so that wasn’t possible. Yet with this plaster that I made from loofah and cassava, I’ve made my house more beautiful. My walls don’t have holes anymore, so the wind doesn’t come in and the house doesn’t get too hot or too cold,” she says.
Alegre de Almada adds that applying the plaster was easy. She did it with the help of two teenage children, and isn’t planning on painting it. She likes the natural beige colour.
Paul JeffreyLearn more about Elsa Zaldívar