At Lalgadh we have been testing a building material that could revolutionize the construction of new houses in the villages where we work. We acquired the key equipment and two recent visitors were able to take it out and work with our technical staff at Lalgadh to build the kit and test the result.
We are often asked if we can help with building new houses when self help groups advocate on behalf of very vulnerable people in their communities. You may remember that with your help we were able to build several new houses for people in Inarwaha village after the floods and heavy monsoon rains damaged them beyond repair. The people affected were extremely poor and quite unable to rebuild by themselves. The work was done using the traditional local materials and will last for maybe 20 years.
The principle in this new approach is to inject a detergent-based foam into a slurry of cement and water as it is being mixed together. The result is a cement “foam” in liquid form, which expands the volume of the slurry by about six times – more than it would expand with sand and ballast, and with much less labour. This foam can be poured into block moulds, or former work and makes a light and strong material with good sound and insulation properties. Our team made former work to build a test wall about 1.8 metres high and about 4 metres long and it seems strong, and hard enough for a house wall. The pictures above show the equipment and below you can see the mixing and the former work.
The resulting wall is about 150mm thick and has a return at each end, and is reinforced with 10mm rebar. Our hope is to develop former work that enables us to “pour” a whole house, one metre depth at a time, so that in three days we can have the walls up to the eaves once the former work is in place. Window and door apertures can be blocked out to leave suitable spaces for ready-made frames. The formers will be reusable, and with enough of them, we may be able to build more than one house at a time. The walls can be rendered, painted, drilled and nailed into easily, are sound and
heat resistant, and in an earthquake are much lighter than a normal wall. The test wall (see left), has good sharp corners and seems pretty hard. Mike Houghton, the initiator of this project, will be going out in November to do some further testing and discuss development of this material. We are very grateful to Chris and Owen Green who have enabled the first step of this new innovation.