This post covers how we built a bamboo tunnel as an entrance to our cobb dome as part of a designEARTH workshop. Unlike our previous build this project was relatively quick and was put up in around two weeks.

As you could probably tell by the title, bamboo was the primary source of material for this project. Bamboo is a useful sustainable material as it grows quickly, often without the need for irrigation or pesticides, reaching maturity in three to five years. It also provides a variety of functions as it is a versatile material with a high tensile strength, that can be shaped into various forms. Bamboo strips are available ready made at the bamboo market in Bangalore, where we got most of our supply for this project from. To better understand the process behind making those strips, we also made visits to a bamboo grove where we felled some bamboo, and learnt how they could be turned into strips.
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The next step was to grind the bamboo strips, removing the waxy green layer and flattening out the nodes to allow the strips to bend easily. Every natural builder is faced with a choice of tools to use. Do you do it by hand, retaining the ethics of sustainable work or do you use power tools to speed the process up? Each has its own positives and negatives. We used a combination of both to learn about both processes. We used knives to peel off the layers by hand as well as angle grinders to get it done quicker. The majority of us were equipped with knives as there were only two angle grinders that were left to be used by those of us with defter hands. This process took around a week, during which the college nurse was kept busy, tending to splinters and accidental cuts.

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The base of our tunnel is made from concrete blocks that are anchored to the ground. The bamboo strips are then attached to them using coconut fiber rope and the clove hitch knot.

We experimented with different techniques of weaving, with some strips woven in straight lines, and smaller strips woven using a cross hatch pattern. We also left a few spaces in the frame to allow for interesting lighting. The ends of the bamboo strips are bent over themselves and secured in place at the entrances, to prevent them from sticking out. Bamboo bends easily with heat, and this was done using a blow torch to bend them slowly. The right application of heat and pressure is a skill that is acquired through practice.

Linseed oil is a wonderful natural varnish that will not only give the bamboo a beautiful sheen but also make it water proof. Unfortunately, we didn't have the time to apply a coat of varnish to weather proof our structure. The monsoon that came after our build was done caused the entire tunnel to collapse a bit and turn black, but hey, it's still standing!

The biggest constraint with this project was our time limit. It was intended as a two week workshop and was also a break from all the cobb work we were doing prior. We managed to get a lot done in this time, but in our haste we overlooked the maintenance, prep and love needed for our bamboo to truly stand out and look good. Nevertheless, this project was an exploration in the realm of possibilities. I had no idea bamboo could bend so much without breaking! Not having worked with it before, I was amazed by the capability of bamboo while also learning useful techniques in its application. As usual, those of us who worked on this project had an amazing time working together to create our tunnel, building friendships and forging bonds while constructing our tunnel.

As with our previous build, the images used in this post collectively belong to those of us who worked on this project and is a part of all our portfolios. Some of them this time aren't the best quality which I apologize for. You may find these images on behance, facebook or the designEARTH website. If you download and use them, please mention designEARTH, Jackson Poretta or Srishti School of Art Design and Technology.

Have you ever made or used bamboo products? What has your experience been like?
Let me know below!

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