Earth Bag Houses Are Dirt-Cheap

Media Watch

In a recent article in the Bali Advertiser, a newspaper for the expat community, Ines Wynn reports about a visit to the Osho Bali Retreat Center and their environmentally friendly and sustainable buildings.

Pupuan Sawah is located in the north-western part of Tabanan, some 8 miles north of Bajera, with postcard vistas of cascading rice fields, expansive rural views unencumbered by villas, hotels or new developments and sleepy villages where ducks, geese and chickens scrabble around on rudimentary country roads. It’s an area that exudes the sought-after authentic Bali, far from the maddening crowds of Kuta, Denpasar, even Ubud. An ideal spot to build a retreat center and create an encapsulating enclave of rest, meditation and healing. The Osho Bali Retreat Center is situated on 2.5 hectares of sloping wooded land in a tiny hamlet called Lalang and contains several buildings and structures conducive to the business of serious meditation. One building in particular stands out due to its unusual building mode. It’s a 120 square meter single level building which houses a 12 person dormitory with bathroom facilities and laundry room. The structure is unique because it is an “earth bag” house, a new concept in Bali and the first building to be constructed using bagged earth instead of brick, batako or wood. It was the idea of Shiv Raj, the affable founder of the Osho Bali Retreat Center. He wanted to build an environmentally sound, ecologically responsible, and economically affordable building, using available dirt on the land instead of concrete and steel. Accordingly, he built an “earth bag house”.

Why earth bags? 
Earth bags are literally bags filled with earth.  Earth happens to be the most readily available and sustainable material today, and the typical Balinese soil called tanah merah (red earth) has a high clay content that makes it ideal for earth bag filling as it compacts into a very hard material. The bags can be recycled sacks made from jute, hemp, flax, linen, even plastic. Think flourbags, ricebags, petfood or feed bags. Ironically, polypropylene bags can be recycled for a truly green purpose since they won’t break down for a thousand years! Bags can be any shape or size that is comfortable and practical to handle.  Most earth bag buildings are constructed with normal bags such as the recycled 25 kg flour bags used at Osho Bali. Some houses are built with very long tubular/cylindrical bags. Earth bags can be shaped in many ways. They can be molded and stacked to make rectangular structures, pods, domes and round houses and incorporate arches and vaults. The walls can be curved or straight, or both, domed with earth bags or topped with conventional roofs. The look can be contemporary or traditional, the style simple to complex and sophisticated. They allow for a great deal of creativity: you can make a hobbit house, a meditation kiva, a sauna dome, a Gaudi-style mansion, etc.

Houses made with earth bags are structurally sound and safe, naturally flood- and fireproof, hurricane and earthquake resistant, unsusceptible to termites and mold. Because they are hermetically insulated, the interior stays cool in hot, tropical climates. Building with earth bags is different from using adobe. Adobe is also a mixture of dirt and clay, but traditionally it’s a more liquid mix that is formed into bricks and cured in the sun. For earth bag construction, the bag provides the form for the dirt and clay, eliminating the need to create bricks.

The building process 
The only materials needed are lots of tanah merah, new or recycled sacks, barbed wire (to prevent the stacked bags from moving), a tamper to compress the soil in the bags and lots of muscle power (one earth bag weighs approximately 45kg). A basic knowledge of building is helpful. A tamper is usually made of a wooden pole with a heavy metal or wooden plate attached. Earth bags are filled on-site from mounds of dirt. After a row of bags has been laid, the tamper presses the bags down into place. This keeps the earth from shifting and keeps each layer level. This compression is also what forces the dirt inside an earth bag to become a solid, self-supporting block.

The foundation is dug in the usual way and bags filled with gravel are layered in the trench to provide adequate drainage. Rubble trench foundations, meaning a trench filled with bags of rocks, gravel or broken concrete, are commonly used with earth bag homes. Walls are gradually built up by laying the bags in horizontal rows in a staggered pattern similar to bricklaying. Flour sacks, as used by Osho Bali, are virtually water proof so there is no leakage and the earth need not be sterilized or treated in any way. Just scoop it in the bags, tamp it solid and mold the bag to a rectangular shape to flatten them for easier stacking.  It does take a few strong guys to lift the bags into place and a pulley system comes in quite handy.

The stacked bags can be solidly held in place by running barbed wire between the rows of bags to anchor them and prevent slipping and sliding, even under the duress of an earthquake. Additional anchoring can be added by putting rebar in the corners and any other stress points. Twine is also sometimes wrapped around the bags, tying one layer to the next, in order to hold the in-progress structure together and add strength. The walls are typically finished with plaster, stucco or adobe to provide a waterproof barrier, to shield the bags from the sun and for esthetics.

Framing for roofing, doors and windows can be wood or other materials. At Osho Bali camphor and mahogany were used. The roof was covered with common Bali tiles. After the walls were up, a flooring surface from poured cement was made the usual way and tiled normally. Other than that, cement was not used in the construction. Electric wiring and piping for plumbing were added in the usual way with the advantage that they could be more flexibly snuggled between the stacked bags. After the shell was put up, the earth walls were plastered inside and out. Special effects can be created on the outside walls by mixing rice hulls into the plaster and letting the plaster dry to a crackly finish, thereby creating a grainy surface. Properly plastering the walls will keep out mold, insects and rodents. Commonly used plasters include mud, a combination of clay and sand, and lime. At Osho Bali the entire building process from start to finish, including roofing, electrical, plumbing and fine finishing, took about 5 months with 6-7 local workers working 6 days a week.

An old idea with a modern twist 
Structures and houses built with adobe, mud, and wetted earth have been built for thousands of years. Building houses with earth bags started in the 1970s and ‘80s. And the idea came from adapting the use of sandbags which have long been used for creating strong, protective barriers or for flood control. The same reasons that make them useful for these applications carry over to the building of houses. Since the walls are so substantial, they resist all kinds of severe weather and also stand up to natural calamities such as earthquakes and floods. They can be erected simply and quickly with readily available components, for very little money. Earth bag building became popular with aid agencies in poor and disaster-struck areas as a quick and inexpensive means to provide shelter for people who lost their homes in floods or major earthquakes or simply as an affordable way to provide decent housing in poor areas.

Affordable and economical 
The ease and simplicity of building with earth bags is evident. The entire structure can be built very inexpensively. Besides the availability of local earth, there is a lot of unskilled labor available that can be tapped for building the earth bag homes. This not only makes the process more affordable, but also more feasible in remote areas where many common building skills are lacking. Labor in Bali is still very affordable; the soil is readily available and free if it is dug onsite. Recycled sacks are cheap.  For the dormitory at Osho Bali 2,600 flour sacks were used costing about 700 Rupiah each (ca. 7 cents); barbed wire was Rp. 3,000,000 (ca. US$ 300). The roof is covered with inexpensive Balinese tiles, the plaster inside is lime cement, and the outside is mud plaster. In all, Osho Bali spent 20 million Rupiah (ca.US$ 2,000) for all the building materials in the entire structure. After adding all the modern conveniences like plumbing and bathroom fixtures, electrical wiring, ceiling fans and air conditioning in the laundry room, the finished building cost less than Rp. 115,000,000 (ca. US$ 11,500) in total, including labor.

Environmentally sound 
Earth bag building fills a unique niche in the quest for sustainable architecture. The bags can be filled with local, natural materials, thereby eliminating most of the manufacture and transportation of building materials. The fill material is generally local earth or other materials such as crushed volcanic stone, perlite, vermiculite, or rice hulls, even rubble. Because the filling generally is of mineral or inorganic composition, it is not subject to decomposition (even when damp), attractive to vermin, or flammable; in other words it is extremely durable. The fill material is generally completely non-toxic and will not leak noxious fumes into the building.

Due to its earth friendly materials, the earth bag building is incredibly green. The bags and their fillings come from recyclable and re-usable materials.  Due to the superb insulation of its 20-cm thick walls, the building remains cool and does not require air conditioning.  A ceiling fan provides adequate air circulation. And best of all, it is a great way to be instantly connected with Mother Earth.

So you want to build an earth bag house?
When Shiv Raj decided to build an earth bag structure he turned to the internet for research. He found a plethora of websites with valuable information on the advantages and the know-how to build an earth bag house. For the do-it-yourselfers the internet is an invaluable source of information and step-by-step How-to videos on YouTube. Beginners can start with a doghouse, a henhouse, a garden shed, raised garden beds or planters, or any kind of enclosure that would enhance your compound. However, nothing beats advice from the pros. Osho Bali will be holding an earth bag building workshop at the Center in January, and take participants through the actual hands-on process by building a house for one of their staff. It’s the best hands-on training you can wish for with many tips and lessons from the experienced people who built the Osho Center dormitory and encountered and solved the all too unavoidable snafus one is confronted with while trying to build something solid in Bali.

Article on Bali Advertiser:

Read our article on the Osho Bali Retreat Center

Update 2014: this centre has now been closed.

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