We treated all the bamboo poles with borax. We first drilled a hole through the centre of the poles using a 6m long drill bit, yes, 6m. We got our welder in town to weld a 1/2” drill bit onto a 6m long piece of rebar, he thought we were crazy but it worked surprisingly well. Then we raised the bamboo vertically and poured in borax solution whilst rotating the pole. We later decided to drill two holes because the borax was taking so long to drip through, it was so easy drilling the holes that it saved a lot of time. With the 9 meter poles that are sticking out of the roof in the pictures we had to drill from both sides, it took a while.

The original idea was to simply paint the columns with borax dissolved in water, and we did this a few months ago with our lintels which (compared to untreated wood on site) still look brand new and mold free. This was until we learned that the neighbour had am 8m long half-barrel trough that he made for treating his own beams a few years ago. So a team of us headed across the fields to fetch it.

We soaked all of our wood in a mix of 15kg Borax, 10kg Boric Acid and 200l water, heated to around steaming temperature. We crammed as much wood into the trough as possible, and any wood that wasn’t underwater was rotated each day to ensure all wood had its time submerged. We also took the opportunity to scrub mold off the wood that had already grown.