- Building Type : Other building
- Construction Year : 2013
- Delivery year : 2015
- Address 1 - street : Kaza 172114 HIMACHAL PRADESH, India
- Climate zone : [H] Highland Climate(mountainous terrain).
- Net Floor Area : 580 m2
- Construction/refurbishment cost : 155 000 €
- Cost/m2 : 267.24 €/m2
Primary energy need :
(Calculation method : Other )
In partnership with the Spiti Projects Charity, the Auroville Earth Institute has designed and built theKaza Eco- Community Centre with key participation of villagers in Kaza and local earth craftsmen of the Spiti Valley. The centre aims to provide amenities for the community which are valuable for local cultural heritage, while providing access to certain essential facilities for health care. The following will be managed by various local cooperative groups:
- An Eye clinic for testing and treatment of severe eye disorders due to high altitude UV exposure.
- A Dental clinic with dietary specialists.
- A Library for information on traditional culture, craft and medicine.
- A Craft Centre and small shop for the traditional skill of hand-knit socks and shawls.
- A Community kitchen and meeting hall for the practice of traditional dance and folk music, meetings, celebrations and festivals in winter.
- Homestay facilities to make the community centre sustainable in the long term and to cater to the needs of local people from outlying villages who commonly walk >50 km to reach Kaza for the use of health care facilities.
Located in the remote Spiti Valley, Himachal Pradesh, India, the building, which consists of a stonemasonry foundation, raw rammed earth walls, and compressed stabilized earthblocks, has been designed especially for the harsh winter climate of Spiti. Trombe walls have been incorporated for passive solar heating of the buildingduring the winter, and for a fully self-sufficient building which does not relyon imported wood as is commonly practiced in the valley. As the region is proneto seismic activity, extensive earthquake-resistant features have been integrated, hybridizing vernacular techniques and certain low-tech modern innovations to improve building performance.
The primary construction technique employed for the Community Centre is the traditional Spiti rammed earth technique (‘Gyang’), an ancient Tibetan building technology which is one of the truly exemplary living traditions of earthen construction still practiced in India. By introducing modest innovations into traditional building practices, the aim of the centre is to reinvigorate acceptance of these centuries old methods, and to demonstrate that the most sustainable, economical and thermally comfortable buildings in this climate… already exist.
See more details about this projecthttp://www.spiti.org/multimedia-archive/kaza-community-centre/
DesignerAuroville Earth Institute (AVEI) Satprem Maïni, Swati Negi, Lara Davis, T. Ayyappan Architectural Design & Construction Supervision
OthersThe Spiti Projects charity Joan Pollock (founder) Charity Sponsoring the Project
ContractorThe Spiti Projects Jeet Singh (Contractor), Tash Bodh (Site Supervisor), Ramesh Lotey Site Contractor
Construction companyn/a Local traditional raw rammed earth builders (Pin Valley, Himachal Pradesh)
Othersn/a - The community of Kaza Local stakeholders
Owner approach of sustainability
The Kaza Eco-Community Centre aims to unite the longstanding vernacular building techniques of the Spiti Valley with modern stabilized earth technologies and structural reinforcement to respond to the needs of climate appropriateness, earthquake resistance, minimal transport of construction materials, and passive heating. By using traditional constructive knowledge, the project valorizes local masons, optimizes locally sourced building materials, and demonstrates to the community the continued relevance of their traditional building cultures. By merging this with innovative elements, the building is able to adapt to climate change, improve on its seismic resilience, and explore additional passive heating techniques.
The Eco-Community Centre is a multi-purpose space designed to provide space for clinics, craftshops, rest, and guest lodgings. Fifty centimeter thick raw rammed earth walls provide thermal mass and insulation against the frigid winter temperatures. Additionally, a trombe wall has been installed to create passive heating. Bamboo reinforcement at the corners and CSEB u-beams protect against the potential seismic activity in the region. Instead of the traditional earthen roof of the Spiti Valley, a composite roofing system was installed to respond to the increasing rain in the Spiti Valley due to climate change.
DESIGN CONSIDERATIONS, CONSTRUCTION TECHNIQUE & EARTHQUAKE RESISTANCE:
The main climatic and geophysical factors in the valley that have impacted the design strategies for this building include: 1. Geographic isolation, 2. High altitude desert climate, 3. Extreme temperature fluctuations (-40°C in winter and +40°C in summer), 4. Presence in a Himalayan Seismic zone. Maximum use of local materials and locally adapted techniques is the base best strategy for the first three factors.
Wall Structure: The primary construction technique employed in the construction of the community centre is the local Spiti rammed earth technique (a several hundred year old tradition), which is supplemented with CSEB in key locations. For this traditional technique, the type of soil is selected from natural quarries in the mountainsides which have appropriate clay content and a large fraction of very coarse gravel and pebbles to reduce shrinkage cracking. Several days before ramming, the soil is prepared and the clay is activated by saturating deep holes opened by pry bars, then the soil is mixed a number of times until the moisture content is even. The high moisture content makes the earth much more plastic than usual for rammed earth; the moisture content is between that of rammed earth and cob. The raw, unstabilized earth is rammed into a wooden formwork, first manually by the feet and body weight of the masons (in a movement we affectionately call the “Spiti dance”), and then finished with the aid of wooden mallets and panels.
The result is a 40-50cm thick rammed earth wall of relatively low density with a high degree of entrained air. This makes the traditional rammed earth a highly effective thermal mass wall system, which insulates against the cold and maintains tolerable indoor temperatures even in this sub-freezing climate. 50cm of earth masonry is an optimal thickness for thermal comfort, as solar gain requires up to 12 hours to travel through the masonry, to regulate interior temperatures for night-time thermal comfort. As the rammed earth is raw, un-stabilized earth of low density, its hydrothermal performance is excellent, effectively generating condensation heat with cold exterior temperatures.
Seismic Resistance: Spiti, which falls within Indian Seismic Zone 4 (out of 5), is a remote region with difficult terrain that can easily be impacted by earthquakes and landslides. The Community Centre was designed with the following strategies to improve its seismic resistance:
1. The overall building proportions and wall thicknesses were carefully determined for earthquake resistance.
2. Inspired from the local rammed earth formwork, AVEI has developed a special formwork system to improve the lateral and seismic resistance of the traditional rammed earth walls. The formwork was designed with ‘L’, ‘X’ and ‘T’ junctions to improve the strength of walls at corners and intersections and to incorporate short buttress walls (50cm x 50cm) on long spanning walls, external wall junctions and corners. The buttresses divide the building into bays for improved overall stability of the structure and also serve a dual purpose for the installation of trombe walls.
3. Extensive horizontal reinforcement with both traditional and contemporary seismic engineering solutions was incorporated into the building. All corner junctions and buttresses in the rammed earth walls were reinforced with the traditional system of alternating wooden strips. This creates a woven structure at critical junctions and buttresses, with 1 meter long strips placed for every 20cm layer of rammed earth. The building is also tied horizontally with composite earth ring beams (developed by the Auroville Earth Institute) at foundation, plinth, sill, lintel and roof level. The U-shaped CSEB blocks are used as a lost shuttering for cast reinforced concrete. This avoids the labour and expense of conventional concrete shuttering and dramatically reduces the overall amount of steel and concrete required. Thus, the secondary building system – CSEB (with 5% stabilization) –is only employed where needed for horizontal reinforcement and corbelling.
Ceiling/ Roof: A double ceiling, sandwiching wood shavings and polystyrene, prevents heat loss through the roof. On top of the second ceiling, a rammed earthen layer of 25cm has been laid for additional thermal insulation. Traditionally in Spiti, this earth-insulated roof system is laid upon a structure of local timber and smaller wooden branches. However, wood is no longer available in the region, and extreme climatic change is forcing adaptations to the vernacular method. A high altitude desert climate, Spiti has historically been shielded from rain by its high southern range. However it has begun to rain in increasing volumes in the last 10-15 years. The traditional roof system was developed for light snow loads (which is shovelled in winter) but was not designed for the heavy loads of saturated soil from rains. Therefore, as a compromise to an ideal sustainable approach, steel I-beams were used for the structure of the floor/ roof systems.
Local plaster (1st floor): The local plastering technique for exterior walls is done with a clayey soil called ‘tua’, which is locally available in large sedimentary deposits in the Spiti River valley. It has a slightly expansive clay, which swells with moisture to provide an excellent natural waterproofing. Plaster is thrown onto the wall and spread with fingers in a circular pattern, a texture that demonstrates a unique regional aesthetic. Lime washes are also used for exterior walls. Yet, the annual maintenance required for these techniques has progressively made local people turn towards cement plasters. The first floor façade has been plastered using ‘tua’, since it does not come into contact with accumulated snow and does not need to be particularly water resistant.
Lime stabilized plaster (ground floor): AVEI has introduced lime based earth plasters for portions of wall susceptible to greater wear (e.g. ground floor exterior walls exposed to standing snow). Lime plasters bond well with the rammed earth walls, protect the raw earth better than the local technique, are less maintenance intensive and continue to gain strength for many years after application.
If you had to do it again?
OBSTACLES ENCOUNTERED & SOLUTIONS:
Initially, the Auroville Earth Institute made the mistake of conceiving of the rammed earth work itself along the lines of an imported European rammed earth system: steel rammers, high compaction ratio, optimal moisture content, etc. (as usually done for rammed earth). However, the first tests with the masons indicated that this would not work effectively. The formwork was designed for this special context and adapted from the traditional formwork; therefore, on a technical level, a high degree of compaction was producing flaws in the rammed earth. However, the technical difficulty opened the doors for discussion with the masons and ultimately resulted in a much more collaborative process: the masons demonstrated the local technique with comments on the benefits of this method. The Auroville Earth Institute was able to learn a great deal from the local masons and better understand how and why this technique was so well adapted for the local context. Ultimately, the community centre could be championed by the local builders as a successful model of innovation which still employs the traditional method. In competition with concrete in the market, this was a very valuable turn of events for the community of traditional builders.
Another challenge was that the construction season is so short in Spiti on account of the long, harsh winters. Construction work generally commences May/June after the snow melts on the Spiti river shelf and ends in late September when the snow begins again. Furthermore, for one month in the height of this short construction season, all masons leave for the annual pea harvest (the main income for the valley). This leaves less than 5 months for construction. Buckets of water on site often freeze overnight through June, and running water and electricity are rarely available when needed. Further, the precarious mountain roads from Manali have recently been open for only 3 months of the year, and the roads from Shimla have been fraught with severe landslides which often strand truckloads of needed material for several months at a time. The only way to manage these challenges is to plan exceedingly well, to improvise in the face of impossible material constraints (expressed by the Hindi word “jugaad”) and to work very hard.
Building users opinion
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.
- 1,00 kWhpe/m2.year
- 1,00 kWhpe/m2.year
- 1,70 W.m-2.K-1
- Solar thermal
- No domestic hot water system
- No cooling system
- Natural ventilation
- Solar photovoltaic
- Solar Thermal
- 250,00 year(s)
Life Cycle Analysis
Indoor Air quality
Health & Comfort
Compressed Stabilized Earth Blocks
Auroville Earth Institute
Gros œuvre / Structure, maçonnerie, façade
Compressed Stabilized Earth Blocks (CSEB) are unfired earthen blocks made by combining soil with a small amount of sand/gravel and between 5 to 8 percent cement or lime stabilizer. These components are mixed and manually compressed with the Auram 3000 press. After curing for 28 days, they attain their full strength which rivals that of concrete block or fired brick with a dry compressive strength of 7.5 MPa.
As soil can be quarried directly from the construction site and the blocks produced there, the transportation cost for materials is reduced, and it provides an opportunity for local unskilled and semi-skilled labor. The lack of firing greatly reduces the pollution produced by manufacture and does not contribute to deforestation for firewood. At the end of life of the CSEB, it is ultimately biodegradable.
Within a 5 year period, CSEB technology has been successfully disseminated to the extent that all new constructions for certain local monasteries have been built with CSEB by locally initiated construction companies.Embodied energy of CSEB 548.52 MJ/m3. Carbon emissions CSEB 49.366 kg CO2/m3.
The Spiti Valley is situated in the Greater Himalaya Mountains, just over the Tibetan border in the Indian state of Himachal Pradesh. Most of the ancient monasteries and forts of Spiti – some, recognized heritage architecture over 1,000 years old – are built with either rammed earth or adobe. Earth has historically been the primary building material for all building types of the valley, and for good reason. At an altitude ranging from 3,800 to 4,500 m, Spiti is a high altitude desert region above the treeline with very limited local resources for construction. Its remoteness and the precariousness of its mountain roads likewise make the import of building materials dangerous and expensive, particularly as heavy snowfall cuts the valley off completely for more than 6 months each winter; yet earth is an abundantly available local material. Spiti’s extreme climate makes earth equally superior; with temperatures reaching -40°C in winter and +40°C in summer, earthen walls provide excellent thermal mass and insulation against the harsh, sub-freezing conditions of winter and the high-altitude UV exposure of summer.
In comparison, concrete buildings have completely inadequate thermal properties and are virtually unliveable in winter periods.
Yet despite the clear environmental, economic and human comfort benefits of earth, market forces and urbanization in India have caused the concrete market to creep far into this remote area, and to begin to replace traditional earthen construction. According to locals, the villages of Spiti valley are now “99% earth, 1% concrete”, while the valley’s capital, Kaza, is “1% earth, 99% concrete”. This trend of urbanization – along with climate change in the Himalayan range (e.g. the onset of regular rains in Spiti for the first time in recorded history) – places enormous risk to the built earthen heritage and traditional constructive culture of the valley.
With this background – and many years of collaboration between local Spitians, the Spiti Projects and the Auroville Earth Institute – the Kaza Eco-Community Centre aims to promote renewed use of traditional Tibetan building techniques and materials in the valley, while introducing a number of modestly innovative features to improve the seismic resistance, thermal comfort and energy efficiency of buildings in this context. For example, the centre has introduced “trombe” walls with a special ventilation system for passive solar heating in winter, to reduce the heavy consumption of firewood for domestic heating.
Land plot area
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- Clémentine Thenot