Living rammed earth wall

Once earth construction is completed, humans’ role ends but nature takes part in reshaping the earth form. Rammed earth façades consistently change through the gradual erosion process. If they are not protected by long overhangs, rainwater washes away the fine soil particles of the earth walls, therefore rough aggregates underneath are exposed. This is the usual weathering process of most earth walls.

Interestingly, the myeongrang house I built for my dog has exhibited the next step of the erosion process. After 3 years of completion, a new living organism has grown from the eroded areas of the rammed earth walls. Moss covered the wall, creating a carpet-like texture. More interestingly, the population of moss was different according to the exposed level of sunlight. Moss sparsely grew in the most sunlight exposed areas (the southern areas), while it widely grew in the semi-shady areas (the western areas). Because humidity is more important than photosynthesis for the growth of moss, it seems that it populated more in the semi-shady areas because they do not lose moisture from strong sunlight.

The changing rammed earth’s façade reminds us of two important lessons. Firstly, earth buildings minimise carbon footprint throughout the life cycle by returning to where it comes from at the end of its use. Although this myeongrang house was eroded severely due to no overhang (it was intentionally/experimentally designed in this way), a long overhang and a raised plinth can certainly protect rammed earth walls from rainwater (4 rammed earth walls I built for the rain test for my PhD research are the evidence and this test will be shortly published in a future paper). The Second lesson is about design potential. The moss grew in the myeongrang house shows a possibility of incorporating a micro-organism as the design element of rammed earth façade.