Building A Low-Cost Bamboo and Mud Yurt

The construction process of the bamboo and mud yurt began with laying the foundation. Our carpenters poured a ring foundation and four bore pile foundations were laid, with rebars added to fix the bamboo poles in place. After the ring beam and oculus were made from laminated bamboo, they were supported in place by scaffolding.

With the foundation in place, students began to build the frame of the yurt. Bamboo poles were selected and cut to size, with measured markings to indicate intersection points. Assisted by scaffolding, the poles were dropped into position from above onto the rebar and the structure was temporarily fixed along the ring beam.

Holes were drilled through the bamboo poles and ring beam and all intersecting poles were fixed with bamboo pins and excess trimmed. Where the ring beam and the wall poles met they were fixed with a combination of bolts and pins. In instances where there was a gap between intersecting poles requiring drilling and bolting, a rope tourniquet, also referred to as a butterfly knot, was used to bring the poles flush together. For cases where a gap still persisted, a small piece of bamboo was inserted into the gap, and then the poles could be drilled and bolted together to create a firm connection.

To add the rafters, bamboo poles were laid between the oculus and the ring beam.
The inner layer of bamboo rafters were connected first followed by the outer layer, and then all the points where the rafters crossed were drilled and bolted together.

To create a base to hold the mud wall at the desired angle, bamboo splits were woven between the poles of the wall structure in a similar way to basket weaving. We then began to make a cob mix using our feet to combine the sub-soil, sand and water. To enhance the strength of the cob, a mixture of bamboo sawdust and coconut-chopped rice straw was added.

It is important to note that the specific ratio of these components is dependent upon the type of soil being used. Testing the ratios of clay, sand, and silt in the soil you plan on using for earth building is essential, as any miscalculations can lead to potential issues such as cracking, improper drying of the wall, or compromised structural integrity. In the case of the rich clay soil we have in Bali, our typical cob mixes consist of three parts sand to one part clay. However, it is imperative to adapt this ratio depending on the specific composition of the soil available.

Once we had the cob mix we began to fill the cavities between and over the top of the bamboo weave. Decorative eye-shaped holes were left in the wall and bamboo lidi was tied in place to indicate the curves of the top of the wall. Lidi in Indonesian means stick, a bamboo lidi however is a long, very thin piece of bamboo carved from a bamboo pole. We continued weaving bamboo splits and filling them up with cob up until this line.

An oval door was made using laminated bamboo strips, slices of bamboo, banana paper, and glass at our factory. Because of the angle of the wall of the yurt and its curve, the installation of the door posed a challenge. We cut the bamboo poles back bit by bit where the door would be placed, and with a few adjustments and the addition of more bamboo above the door, we managed to lift the door in place with a big team effort and secure it.

The next step involved the creation of a long lidi bundle, which would encircle the perimeter of the rafters, providing structural reinforcement and support to the roof.

A lidi bundle is formed by bundling a number of lidis together. Lidi bundles possess excellent flexibility, allowing them to bend easily. Consequently, they serve as an ideal choice for edging roofs and forming curved and organic shapes.

Once the lidi bundle was assembled, it was lifted into position and secured onto the eave of the rafters using bamboo pins. To optimize natural light within the yurt, a grantangan roof detail was incorporated. This involved the manual carving of angle joints, reminiscent of fish mouth joints, onto the ends of 48 poles using traditional Balinese knives called mutiks. These were then fixed into their designated positions on each rafter, allowing the roof's edge to gracefully uplift.