For column we need to select a strong thick walled dry bamboo. Whereas a thin walled bamboo can be used for construction of wattle and Daub. Bamboos with thin walls are easier to split thus they can be efficiently split and bent as walling members. These bamboos can be used directly after treatment as they are more flexible when wet.
1. Boric Acid
1. Boric Acid : 1 Part
2. Borax :1.5 Part
3. Water : 100 Li
We need to dig a pit big enough first, to accommodate the largest of your bamboos. The pit must be carefully lined with tarpaulin sheets to prevent the solution from draining. After the pit is dug it is easy to calculate the quantity of water by calculating the volume of the pit. Then we can carry out reverse calculations to arrive at the quantities of the Boric- Borax required.
Simultaneously holes (4mm dia) must be drilled onto the bamboos. Care must be taken to drill the holes 1-2” above each node. This will allow the Boric-Borax Solution to enter the inside of the bamboo and render the starch inedible for the potential pest (Boring Beetles).
The Boric Acid is available in a powder form (Boric Powder). Boric Acid is made from Borax which is a naturally occurring salt. Both the ingredients are mixed in the given proportions with warm water in a small bucket first to dissolve the salt and remove all the lumps before adding to the pit filled with water. We can do this in small batches.
After the solution is made the bamboo must be carefully dipped into the solution. Care must be taken to immerse the bamboos completely; we can place long stone slabs onto the bamboos to make sure that they are completely dipped.
The bamboos must be treated with this solution for at least 15 days before they can be used. After the bamboos are removed from the solution, they need to be dried, by keeping them vertical in a shaded area.
The bamboos used as columns should be coated with Bitumen up to the plinth level.
Note : The split bamboos used for the wattle and daub can be alternatively coated with lime slurry where treatment with Boric-Borax is not feasible.