(R)ETRACING THE EARTH: THE UNDERGROUND APPEAL —

In collaboration with Joy Hori from Afro Archi and Elie Gaborit from Earth Construction Bali
Retracing the past starts from the ancient technique that has been used over million years that had built the base of civilization we are currently living in. Environmentally friendly construction techniques that are rarely discussed, Rammed Earth, exhibits the role of engineering and Earthy-material selection that affects upstream to downstream behavior towards a #responsiblelifestyle.
Joy Hori is a Burundi-based architect, who gains interest in promoting rammed with @afro.archi, a community that celebrates rammed earth knowledge and exploration in Africa
Elie Gaborit from Earth Construction Bali has been in construction practice for over 6 years in Indonesia, having projects range using rammed earth, bamboo, and timber
#1 Sustainable Ancient Compaction Technique with Artisanal Quality
Rammed earth is a compaction technique of natural raw materials such as earth, chalk, lime, or gravel, to be used as foundation, floors, or walls. It provides good thermal insulation, fire proof, and sustainable for its reuse value if the building is demolished.
Heritage values, bioconstruction, and sustainability are three factors closely related to rammed earth buildings, which make it an advantageous construction technique that should be preserved and adapted to modern times
#2 Bioconstruction: When explorations between materials and chemicals matter
A fully sustainable rammed earth should not contain any artificial chemicals. However, a tiny amount of cement is required as stabilizer, or as termite solution on the base. The size of the particles that is composing the soil also matters, something soft is better. Wet soil treated with lime or quicklime, is a very effective method for drying. The lime reacts with moisture in the soil to generate heat, drive off water vapor, and bind some of the water in the chemical reaction.
Explorations in materials ratio, texture, and marbling become important in constructing building with Rammed Earth. Ratio is different for different soils, but suggested number is 80% soil, 10% clay, 10% water. Texture is resourced from different type of soils, usually limestone for lighter colors. Coloring is also available by artificial and natural chemicals additions, such as iron oxide pigment.
#3 Modulation plays important role, surprisingly.
Form works and the frameworks become important tools to cast the materials. For instance, Earth Construction Bali used a module of 240 in length and 60 centimeters in height. Longer time will happen if the space size is not aligned to current modulation, which happens a lot since many architects have not been aware yet with this concern. The first stage is to lay the first form work above the stone foundation. And as the first floor block is filled, second form work is laid on the top of the first, and keep going.
#4 No need finishing or polishing after the work’s done.
Takes normally 3 weeks for the rammed earth to get dried, with normally wall thickness of 20-30 cm. As a retaining wall, rammed earth can achieve up to 3 stories height. Filling the layers of 4x5 m room will take 2 days, and the medium size house usually takes 4-6 weeks to finish. In Africa, it costs cheaper than concrete construction. However, in Indonesia the price is still relatively the same.
Text by Azzahra Dartaman
Go to RRROAR Virtual Universe for deeper understanding here