Eco community centre, Kaza, Spiti valley

KAZA ECO-COMMUNITY CENTRE Authors: Swati Negi, Lara K. Davis Date: November 14, 2014

Located in the rain shadow of the Greater Himalayas, adjacent to Tibet on the eastern border and Ladakh on the north, the valley of Spiti is one of the least populated regions in India, with a population of ~10,000 scattered over an area of ~7,500km². The mountainous desert climate and geographical complexity of this region combine into a barren landscape with virtually no uncultivated trees. Having been functionally isolated for centuries, the local culture is introverted with highly collective social patterns. The remoteness of the valley and abject scarcity of resources have been the dominant factors driving vernacular innovation towards appropriate resource management. This is best exemplified by Spiti‟s material and energy efficient building practices.

Kaza, the sub-divisional headquarters of Spiti (population ~ 3000) is situated along the bank of the Spiti River at an altitude of ~3,600m above mean sea level. The village is an important trading post with a modest market drawing vendors and tourists throughout the summer. The warmth and kindness of the local people along with the virgin allure of the mountains have contributed to making Spiti an ever more popular tourist destination. By consequence, this remote region has been burdened by the problematic market forces driving development today in India. Like most Indian villages, Kaza is growing rapidly with little regulation to protect its recent past heritage as a small mountain village of 13 large families with abundant farmland.

Joan Pollock, founder of the charitable organisation „Spiti Projects‟, has dedicated 21 years of her life to assist in improving the health and living conditions in Spiti (e.g. including improving access to education, clothing, medication, etc.). The organisation‟s many years of collaboration with local people – as well as sensitive knowledge of the local culture, religious beliefs and basic ideals governing lifestyle – has given it a unique insight into the needs of the present and future generations in the local community. These years of discussion with the Spiti people have culminated in the project of the Eco-community centre.

This project was designed and built by the Auroville Earth Institute (AVEI), the representative for Asia of the UNESCO Chair “Earthen Construction, Constructive Cultures & Sustainable Development”. AVEI, founded by Satprem Maïni in 1989 and based in Auroville (near Pondicherry), South India, is a global leader in the development of alternative earth based construction techniques. Comprised of an architecture department, a research cell and training program, AVEI specialises in a wide range of vernacular and modern earth based construction techniques, including compressed earth block, rammed earth, poured earth, alternative foundations for buildings, etc.

The Kaza Eco-community Centre aims to offer amenities for the local people to strengthen local cultural heritage, while providing access to certain essential facilities for health care and community oriented services. The main motive of the building is to hybridise vernacular technologies and modern innovation, to build upon the rich local building culture and provide modest new innovation appropriate to the context. The participation of local craftsmen and masons is critical.

By valorising traditional building practice, it is possible to challenge the unsustainable new trends in construction in the area, to dissolve myths about the longevity of earth buildings and to question the appropriateness of industrial building materials like reinforced concrete for the climate of Spiti.

The valley remains cut off for the better part of winter, as the passes are closed due to heavy snowfall. The limitation of mobility poses a challenge particularly for medical emergencies. Although Kaza has a government hospital, it has limited staff and infrastructure. The community centre includes an eye clinic and a dental clinic, as these facilities are currently not satisfactory in the valley. At present there is no fully functional dental facility in Spiti, which forces the locals to travel all the way to Shimla or Manali for assistance i.e. ~200km on extremely rough roads. Many locals have severe eye damage due to prolonged exposure to direct and reflected UV light in the high altitude, snow-covered climate.

The community centre hosts a library and crafts centre to provide a warm, well lit, indoor environment for the practice of arts native to the valley. The harsh living conditions during winter encourage collective practices, as multi-family gatherings rotate between houses to conserve resources. Villagers spend this time for celebrations ranging from tribal ritualistic ceremonies to marriages. During the long winter hours, men and women sit around ‘tandoor’ stoves and practice the local craft of weaving and knitting, making products like carpets, shawls, rugs, and socks, which they sell in summer to make a living. Many villagers study ancient literature about Buddhist practices, Tibetan medicine, etc.

The community centre also has a number of rooms for accommodation, to cater to the need of local people from outlying villages, who have to walk up to 50km to see a doctor in Kaza. The centre has a kitchen and meeting space to make it self-sufficient. These facilities will also be supplemented with eco-tourism so that the centre can financially sustain itself. The high influx of tourism in recent years has had clearly visible repercussions in the changing market trends in the valley. The co-existence of tourism and local practices is a critical balance that the community centre will strive to create. The program is designed to mix local services with tourism to more sustainably channel the forces introduced through tourism and to make it an asset for the host communities.

Fig. 1: Ground floor plan

Fig. 2: Spiti context (winter)

DESIGN CONSIDERATIONS AND STRATEGIES: The main climatic and geophysical factors in the valley which impact design strategies include: 1. Geographic isolation, 2. High altitude desert climate, 3. Extreme temperature fluctuations, and 4. Seismicity. As Kaza is situated in the greater Himalayas, it experiences harsh weather conditions with extreme winter temperatures below -35˚ C. There is a significant range of temperatures, annual and diurnal, with summer temperatures reaching the opposite extreme of +35 ˚ C. Due to the unstable nature of the Himalayas, this region falls within Seismic Zone 4 (out of a scale of 5).

Earth is the primary building material in Spiti with a rich traditional building culture more than 1000 years old. Most ancient monasteries and forts are made of either rammed earth or adobe blocks, some of which are top heritage buildings in India. Structures are typically built with a high stone plinth to protect the base of the building and reduce the exposure of raw earth to freeze/thaw effects, which result from contact with snow. Building with earth is highly appropriate in Spiti according to the climatic and geophysical constraints: it is abundantly available and does not need to be transported over dangerous rural mountain roads, it has excellent insulating ability, and it is appropriate for seismic resistance and sub-freezing climates.

Since the introduction of cement into the local market, many Spitians prefer to build with concrete block technology, due to its apparent affordability, availability and ease of construction. The cost of cement, which is highly subsidised by the Government of India, makes concrete construction competitive with other construction materials, even in extremely remote locations such as Kaza. However, concrete block has a very low thermal mass, which makes it unsuitable for cold climatic regions. Prejudices with regards to the viability of earthen building practices have risen primarily due to ignorance, false myths from the concrete industry and poor attempts to work with a combination of

earth and cement. This project aims to break through this prejudice and create awareness about alternative technologies which minimise the maintenance requirements of earthen buildings.

Fig. 3: Mixed development in Spiti

CONSTRUCTION TECHNIQUE AND EARTHQUAKE RESISTANCE: The primary construction technique employed in the construction of community centre is the vernacular Spiti rammed earth technique. In this technique, moist raw earth (with no additives for stabilisation) is rammed into a formwork manually by the feet and body weight of the masons and then finished with the aid of wooden mallets. The resulting masonry is a 50cm thick wall of a relatively low density, which gives it high thermal mass and insulation properties.

Inspired from the local rammed earth formwork, AVEI has developed special formwork system to make the walls more seismically resistant. „X‟ and „T‟ junctions are designed into the formwork to incorporate buttress walls (50cm x 50cm), which give lateral stability in the event of a seismic event, and also divide the building into bays for improved overall stability of the structure. The buttresses also serve a dual purpose for the installation of trombe walls (see Solar Passive Heating).

Fig. 4: Vernacular rammed earth technique

Fig. 5: Mason ramming earth in formwork

The corners and critical junctions of the rammed earth walls have been horizontally reinforced with wood / bamboo elements of up to 1m in length. With each 20cm course of rammed earth, the reinforcement alternates direction along the main axes of the building. The woven structure of reinforcement provides critical support in the corner junctions and buttresses in the advent of an earthquake.

Fig. 6: Rammed earth walls

Fig. 7: Corner reinforcement with twigs

The secondary building element employed is the modern stabilised earth technique, Compressed Stabilised Earth Blocks (CSEB). CSEBâ€&#x;s are composed of soil and sand, which is stabilised with a low percentage of cement (approximately 5%) and then compressed manually. This technique uses resources available on site and abundantly available in the region, thus practising responsible management of resources. Further, both CSEB and rammed earth are labour-intensive technologies using affordable materials, and therefore they invest significantly more in local economies and livelihoods.

The building has a number of composite earth ring beams for additional horizontal reinforcement, with reinforced concrete cast within courses of U-shaped CSEB blocks. The U-shaped block act as a lost shuttering to avoid the labour and expense of conventional concrete shuttering and to dramatically reduce the overall amount of steel and concrete required. These ring beams ensure that the building is tied at levels of critical discontinuity, thus minimising cracking from typical ground settlement or seismic events.

Fig. 8: CSEB production in Spiti

Fig. 9: Casting ring beam

SOLAR PASSIVE HEATING: The vernacular rammed earth technique is a highly effective thermal mass system, which maintains tolerable indoor temperatures in this sub-freezing climate. For a thermal mass wall system in this climate, 50cm of earth masonry is an optimal thickness for thermal comfort. Solar energy is absorbed into the exterior surface of the wall and can take up to 12 hours to travel through the masonry to regulate interior temperatures. This phenomenon helps to create thermal comfort within the building during the night time.

Local heating methods in winter heavily rely upon the use of firewood, which is extremely scarce in the region. An average family is obliged to use 20 to 50% of their annual household income on firewood for heating purposes.

However, due to the altitude of this region, with clear skies throughout the year, passive solar strategies are an

excellent alternative energy source. To this purpose, trombe walls have been installed on the east, west and South faรงades, to make the building relatively independent during winter for its heating requirements.

A trombe wall is a glass faรงade installed a few inches from a thick mass wall, which, facing the direction of maximum solar exposure, absorbs solar radiation and transmits heat by convection into the building. In the case of the community centre, the rammed earth wall has two vent openings, one at the top and one at the bottom. When solar radiation penetrates the faรงade, it heats up the rammed earth wall and the air in the interstitial cavity, which then rises and enters the through the upper ventilator to heat the room. As interior air cools down, it is drawn out through the lower ventilator, creating a natural convection cycle to heat interior spaces. The ventilators can be closed during the night time to prevent the reverse process.

In cold climates, it is important to ensure that warm air does not escape through openings. The main entrance has a small vestibule which minimises air infiltration and energy loss through open doors. Since up to 40% of heat in a house escapes through the roof, a double ceiling has been used to prevent such heat loss. Wood shavings and thermocol are sandwiched between the two ceilings for this purpose. On top of the second ceiling an earthen layer of up to 25cm has been laid for additional thermal insulation.

Fig. 10: Skin section

Fig. 11: Trombe wall closeup

GREY & BLACK WATER TREATMENT: Traditionally, houses in Spiti employ a soak pit system for disposal of sewage. The sewage is not treated and is directly exposed to the ground, resulting in contamination of ground water aquifers. This has hazardous consequences in this region, particularly in the rapidly urbanising area of Kaza, as local residents rely heavily on hand pumps for their water consumption.

AVEI has introduced a baffle reactor system for the first time in Kaza to passively treat wastewater. This system is comprised of a number of chambers, which direct wastewater in a path of maximum dynamic flow within a limited space. This activates anaerobic bacteria, which assist in the decomposition of waste before it enters a soak pit, therefore protecting the ground water from harmful pathogens.

FINISHES:

The local technique for plastering exterior walls employs the use of a particular type of clayey soil called ‘tua’. Locally available from large sedimentary deposits in the Spiti River valley, ‘tua’ is slightly expansive clay, which swells when exposed to moisture and therefore provides an excellent natural waterproofing. Alternatively, lime washes are also used for exterior walls. This lime wash is a very thin layer which needs to be reapplied annually. Yet, the regular maintenance required for these techniques has progressively made local people turn towards cement plasters.

Ironically, however, cement plasters do not bond well with earth (particularly in the climate of Spiti), and have a very short life span.

Since the first floor façade will not come into contact with accumulated snow, it is not necessary for it to be very water resistant. Therefore, it will be plastered using the vernacular lime stabilised earth technique, as this technique is the most effective, low maintenance option. Plaster is thrown onto the wall and spread with fingers in a circular pattern, a texture which demonstrates a unique regional aesthetic and also functions to limit cracking.

AVEI has conducted various tests for an improved earth-based lime plaster for interior and ground floor exterior walls.

These portions of wall are susceptible to greater wear, making lime based earth plasters a more viable solution. As opposed to cement plasters, lime plasters bond well with rammed earth walls and continue to gain strength for many years after application.

Fig. 12: Lime plaster finish

IN CLOSING: AVEI has explored a wide range of interventions to make a positive impact on the construction sector of this region, while emphasising the appropriateness of local materials and building techniques. Daily visitors to the building site, including local villagers, politicians, monks and foreign visitors, are given tours of the building in an attempt to spread awareness. Through these conversations, the building has successfully stirred up the otherwise suppressed debate about the suitability of cement in this region. Government officials have been urged to take this knowledge forward and continue to use earth for future development. The community centre has set a benchmark, showcasing the intelligence and appropriateness of vernacular knowledge in Spiti.

Of all vernacular earthen traditions formerly practiced in India, the Spiti rammed earth technique is one of the few exemplary living traditions still practiced by local masons. However, one can observe the progressive deterioration of the valley‟s traditional wisdom, as it is abandoned for cheap modern replacements in the form of concrete blocks and tin roofs. The renewed use of traditional technologies is crucial at this point in time to ensure the sustainable development of the valley and the continuity of over 1,000 year old practices and ways of life of local craftsmen.

Fig. 13: View of building from a distance

Fig. 14: View of building

Fig. 15: Interior

Team: Client: Joan Pollock (Founder of Spiti Projects) Principal architect: Satprem Ma誰ni (AVEI Director) Project head: Swati Negi (AVEI Head architect) AVEI Site architects / supervisor: T. Ayyappan (AVEI Co-Director) Lara K. Davis (AVEI Co-Director) Samuel Rodrigues Local Site contractor & supervisor: Jeet Singh Tashi Bodh

Fig. 16: Interior