The bamboo and cotton fabric formwork not only functioned very well to build rammed earth at Earth Workshop Part 2 in Venice but also created an aesthetic form of the rammed earth. The form and texture of the rammed earth was shaped by the innate quality of the materials – bamboo, cotton fabric, and the soil’s compaction and composition.

 

The bamboo of the formwork contributed to creating an aesthetic form of the rammed earth. The horizontal bamboo frame led to creating the smooth and rounded indented curvature of the rammed earth.  This profile was contrasted with the rammed earth that was created with plywood frames and fabric formwork. The rammed earth had a clear rigid indented shape marked by plywood frames. The plywood also caused the fabric of the formwork ruptured easily during the ramming course because the fabric was rubbed by friction between a rammer and the plywood frame. The sharp corner of the plywood frame made the fabric worn easily. But for rammed earth made of the bamboo and cotton fabric formwork, a strong friction between a rammer and bamboo frame did not occur because of the rounded stem of bamboo. So, the cotton fabric was still in a good condition even after completing the ramming course (The detailed construction process can be found at the blog post ‘Building rammed earth with bamboo and cotton fabric formwork / Earth Workshop Part 2 in Venice Architecture Biennale 2023’).

 

The nodes of bamboo are also rendered on the surface of the rammed earth, remaining their distinctive node marks on the waistline of the rammed earth. Also, during the ramming course, the bamboo nodes made a small amount of earth mixture be extracted from the gap between the nodes and the ground floor. It was inevitable due to the natural and heterogeneous shape of bamboo; the bamboo is gradually slender from bottom to top as it is growing with its node, which is different from a standard and regular shape of manufactured timber such as CLS or plywood. When the bamboo and cotton fabric formwork was dismantled, it was found that the formwork lent the rammed earth an attractive form. The rammed earth exhibited its form with an impression that it is growing out of the ground since a sharp boundary between the rammed earth and the floor was blurred.

 

The cotton fabric of the formwork contributed to creating an adorable form of the rammed earth like a snowman. During the ramming course the bottom fabric was bulged more getting more loads on the top, so the bottom of rammed earth was more extruded than the top. Therefore, the fabric played a role in creating not just a geometrical form but also a textural difference of the rammed earth. The most bulged part has a rougher texture than the neck of the rammed earth. That might be due to the difficulty of proper compaction at the most bulged area while the fabric is bulging greater. Interestingly, all of these factors led to creating an aesthetically appealing form and texture of the fabric formed rammed earth.

 

A different soil composition also adds an attractive charm to the rammed earth. The top layer of rammed earth has a slightly sandy texture seemingly looking like a sponge chocolate cake, which is contrasted with the smooth clay clothed layer below.

 

The rammed earth clearly shows how the inherent quality of the material - bamboo and cotton fabric can be expressed on the form and texture of the rammed earth.

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Acknowledgement

Earth Workshop Part 1 and 2 were generously supported by Scotland + Venice and Architecture & Design Scotland.

The photos of the rammed earth were beautifully taken by the artist and photographer Joshua Lee