Bamboo Eco House Build

[Smithson]

About two years ago, my wife bought 4 rai in Nakhon Nayok. We wanted to put a small house there, but weren't keen on the concrete boxes common these days.

I've always been interested in sustainability, especially in building. Trying to keep things simple, I looked at what was possible and realized bamboo was an option. Bamboo is the world's fastest growing plant and poles can be harvested annually, unlike trees which have a turnaround of about 30 years. It has been used by the majority of the world as a building for thousands of years.

Pound for pound it is as strong as mild steel. It has great tensile strength, which is why it is increasingly popular in earthquake zones of South America.

Having decided on bamboo I looked around for varieties.
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The picture above is Pai Liang, a common variety in Thailand. It's a fast grower, with poles of 40-60mm. Despite it's small size, it's very strong and is great for bracing and rafters.



This is Pai Tong (D. Asper). One of the best giant bamboos for construction it's quite straight, with poles of 100 - 250mm in diameter and 20m long.



This photo gives and idea of the growth rate of bamboo. The large shoot is only a couple of weeks old. There are some bamboos that can grow over 1m a day.

While bamboo grows to it's full size in 1 yr, it takes 3 years before it's fully mature and useful for construction. Young bamboo is weak, prone to cracking and more prone to insect attack. We found that most bamboo is harvested before maturity. This was no good for us so we made arrangements with a farmer to select and help harvest the bamboo. The huge poles are like trees, while they're easy to chop down, they get tangled and among the other poles, which makes harvesting a bloody nightmare.

As most ppl know, bamboo is prone to rot, mold and insect attack. To be used for long term structures it needs to be preserved. There are many chemicals used for this, most of them quite nasty. Borax is a very safe and rather than killing pests, it acts more like deterrent.

The method we choose is called sap displacement, this involves using pressure to push the borax solution thru the basal end of the bamboo. A few seconds after the pressure is applied, sap drips from the other end of the pole, as can be seen in this vdo ">