Clay straw wall is an easy to do, low cost, minimum impact and light weight wall construction technique. It does not get affected by termites because of high silica content in rice straw and it provides good insulation. It is a good acoustic and noise reduction. It is solid, durable, non-toxic, and semi-structural (self-supporting within reasonable limits).
How did we construct clay straw partition wall?
Clay straw wall is a very simple technique. We tried a patch of it in a 2ft X 2ft size between two bamboos used as pillars with thickness of 4” without any reinforcements. After the observations on this we decided to go ahead with this technique for partition walls of the prototype houses but with the use of bamboo reinforcements and wooden frames.
1. Clay is mixed in water and mixed well. It is left to soak for a day.
2. Clay settles in three layers- the top clay water, the creamy middle layer and the settled solid lumps at the bottom.
3. The clay water layer and middle creamy layer is taken out onto a bucket.
4. Rice straw is choppedand soaked in clay water for an hour.
5. The partition wall is divided into frames of palm wood in 2ft intervals to provide a frame to which shuttering can be supported by.
6. Shuttering is laid for the required thickness. We had a 7’ tall earth-crete wall of 4″ thickness on which clay straw wall was supposed to be built. So we continued with the same thickness for the clay straw wall.
7. The adjacent walls are made moist with water to gel the clay straw wall well.
8. Soaked straw is laid in the shuttering in horizontal layers.
9. Using a long and lean wooden member with a flat base it is compacted slowly until it cannot be compacted further.
10. After the compaction is done until the brim of shuttering it is left to dry for a day along with the shuttering.
11. The shuttering should not be left as it is after filling is done for more than a day because the straw starts to decay.
12. After removing the shuttering clay straw takes 1 week per an inch of thickness to dry completely in the hot and humid climate of Auroville.