Transforming Earth into Beautiful Buildings
A different perspective
The environment around us is degrading day by day. Certainly there are lots of causes which we are responsible for. So todays’ external world is emphasizing their concern on the choice of construction material governed by ecological consideration. However, we are likely to be surrounded with only concrete houses.
Within the crowd there are some who have a different perception of construction technology: that is Rammed Earth Houses. The first considered Rammed Earth house was Mr. Hemandra Bohra’s residence in Budhanilkantha followed by another residence in Godawari of Mr. Narayan Acharya, who is a beekeeper, organic farmer and builder with a very strong view on sustainability and environmentally friendly building construction; this has resulted in building one of Kathmandu’s most distinctive homes. The property is constructed largely from rammed earth and Bamboo which is locally known as “Mato Ghar” (the building made of clay).
Moving along the busy street from Satdobato to Godawari, leaving various lavish bungalows and concrete apartments, we are led to a typical small village of ancient settlement where we can see a red roofed building with a grace of its own. It is the house with a spot light on environmentally friendly building construction in concept, material and technology, with around 80% of all the materials being recyclable.
Living in earthen homes
Rammed Earth is a technique of building walls using a mixture of selected aggregates, including gravel, silt and clay, into a structural arrangement called form. It is the ancient building technique that has seen a revival in recent years due to an increased interest for sustainable building materials. Traditionally it has been used in many structures around the world, some of them up to seven storeys high. Although most rammed earth buildings are single or two-storey, a five-storey hotel has recently been completed in Australia. The Great Wall of China is also an example of rammed earth. Today the biggest innovations in the technique are in Australia, France and Austria.
In Nepal, we can find rammed earth construction is practiced from the Terai (Plains) regions to the Himalayas. The advantages of rammed earth building are that it’s simple, durable, easy to maintain and environmentally responsible. The only disadvantage is that it is very labour intensive and requires a lot of experience. Consistent workmanship is critical for both the appearance and the strength of Rammed Earth walls. Hence, site work has to be of high quality. As mentioned by Nripal Adhikary (ABARI group) lots of tests were carried out at Mr. Acharya Residence in Godavari before the construction began.
Evolution of Concept
The red PVC sloped roof contrasts with the rammed earthen wall, bamboo and wine bottle veranda in Mr. Acharya’s Residence. In his trip to India, Mr. Acharya experienced compressed block building technology which left an impression that bound him to see different perspectives of construction technology of earth building. So after a period of research and collaboration with Mr. Nripal Adhikary he took up the challenge of using rammed earth construction to explore the new building dynamics. The result was a simple L shape two-story building with a linear arrangement of rooms, which floods all the rooms with light and ventilation. The bamboo colonnade veranda along with projected roof also acts as climate protection.
Technology towards Sustainability and Environment Friendly
“I love to run every morning and collect soil from different places to test every day.” Mr. Acharya says, reflecting his keen interest in the environment. This particular residence adapts the traditional and locally available materials of earth ramming together with layers of soil, sand, stone, dust and occasionally cement, with the addition of bamboo and unused thrown glass bottles, although some machinery equipment used for construction was imported from India.
To construct a wall, first the soil is ground into a fine powder and then filled into the formwork. The 10cm of mixture is then compressed to 5cm. Acharya was careful, as too much clay could shrink and crack the walls. He reinforced the structure with concrete beams and a flexible, lightweight second storey roof truss made of Bamboo structure using Colombian Baharaque to promote better earthquake-resistance.
The main foundation is constructed with stone 35 inches thick and a DPC layer of plastic to prevent damp. The entire tie beam is connected over which an 18 inch wall is constructed. The position of the openings are based on earthquake concept. The upper floor consists of light weight earthen wall with more wood dust, lime and a small amount of soil which is paired with row brick. The wooden pillars are kept 2 ft apart and tied with wood beams and above bamboo tie beams are used to support the roof. Plastic mesh is also embedded into the wall to provide horizontal binding support. The plastering is done with a mud lime surkhi mix which is strengthened using bamboo. The paint is also made from local materials but the main problem seen is the unevenness of surfaces.
Not only is it an environmentally friendly construction, the unique feature of this building is its projected veranda supported by a colonnade system made up of wooden columns and beams using joist hangers to strengthen. Though the roof is made of zinc sheets, bamboo is used internally for support, as well as insulation to avoid the radiated heat that may enter the house during the hot summer days. The use of bamboo, which is lightweight, flexible and durable with seismic resistance, allows some movement during an earthquake thereby reducing the risk of it breaking.
Similarly, the ceiling finish is made with bamboo cut lengthways and then spread out like a sheet. These are also used in the internal doors of the building. The bamboo is product of Adobe and Bamboo Research Institute (ABARI) and are treated using a modified boucherie technique (treatment method using a boron compound and neem solution) which makes the bamboo more durable and resistant towards termite attack and decay. The house is unique for using wooden floors recycled from demolished buildings in Kathmandu with under floor heating and cooling system reducing the necessity of mechanical heating appliances that consume a lot of energy. Although the building can be called environmentally friendly, the use of an under floor heating system, which is a modern technique, is a controversial issue.
Yet another feature of this building is the Reed Bed Water Treatment System, Bio Gas Plant at the backyard including the kitchen and flower garden which are in construction phase. The general planning idea was to create an outdoor kitchen with rammed earth oven that uses the biogas prepared on site. It is estimated that the biogas will provide 80% of the gas required for 6 members of family. The Solar panel installed is generally used to light the outdoor space of the house.
Although all the best methods were put in place to make this a completely environmentally friendly building, the use of imported material: the zinc roof, the costly under floor heating system and also the use of brick and cement mortar slightly undermines the intent.
Rhythmically spaced vertical bamboo shoots create a unique railing creating a powerful image along the pitched roof with traditional expression. The remaining spaces are filled with cut glass bottles as art in the wall of the bathroom with small circular opening to create an artistic expression.
Most people today perceive rammed earth house as old-fashioned and tend to live in the modern concrete buildings. Mr. Acharya’s house stands high as a wonderful example of rammed earth building on Kathmandu Valley. This design of building with traditional materials still continues to fulfill the function of modern life style with equal elegance and grace. These types of buildings also have the advantage of providing a balanced environment to bring out quality space for quality living. Such unique works of architecture preserve our environment and it’s high time that each of us realize our responsibility to understand its essence and work to encourage use of local materials.