Habitat Observatory

    Dhajji Dewari: Creating Earthquake Resistant Houses
  During the 2005 devastating earthquake in Kashmir, traditional Dhajji Dewari houses proved to be earthquake resilient while many other buildings made with modern construction materials collapsed. Majority of buildings in the earthquake affected Kashmir region use unreinforced masonry walls as bearing and enclosure walls. In the last few years, over 120,000 rural houses have been rebuilt using the Dhajji construction technique in Kashmir.

Dhajji Dewari means “patch-work quilt wall”. This kind of a house has a simple square plan. The super-structure of such a house consists of a very elaborate timber framework. All the timber used is well seasoned, so that it does not shrink in dry weather and expand in wet weather. Each timber member is long and is continuous at corners and at junctions of walls.

The seismic advantage of this flexible and ductile inter-connected timber frame is manifold. The timber frame can sustain relatively large displacements without failure of individual timber members. As all timber members are meticulously interlinked, the frame behaves as one single unit during an earthquake when the ground shakes a lot to resist the earthquake force. After the strong shaking is over, the entire frame comes back to rest in almost its original position, barring a few peripheral frayed timber joints. An important aspect of introducing vertical timber members in walls is that these take the load off stiff, brittle and vulnerable stonewalls and become load-bearing elements in the house. It also introduces flexibility and strength to the stone walls. In addition, they restrain horizontal slip of stone. Thus, the collapse of stonewalls is minimized during earthquakes.

In addition to the robust and larger timber frame, a smaller timber frame work is also embedded within the wall. This provides an additional framework that helps in minimising the propagation of earthquake induced diagonal shear cracks in stonewalls. Thus, progressive destruction of interior walls is minimised. Propagation of cracks is what eventually leads to collapse of most stone houses.

In rural areas, the large and small timber frame works are filled with partly dressed stone in the interior walls, and random rubble stone in the outer walls. In urban areas adobe, i.e. sun-dried clay bricks, or burnt bricks are used instead of random rubble.

In addition to these earthquake resistant features, the doors and windows in a dhajji diwari house are few and small and are well-spaced out in the wall. The space occupied by the wooden staircase is negligible in comparison with the overall size of the house. Therefore a dhajji diwari house can be three to four stories high and is still able to resist earthquake forces.

The dhajji diwari style of construction has emerged as a time-tested earthquake resistant technique, indigenously developed in rural areas through repeated earthquake disasters and several generations. It can easily be adapted in urban areas too.

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    World Haus – Affordable, Eco-friendly houses for the Poor
  Affordable housing is a huge problem in the rapidly growing economies of the developing world. According to the UN Human Settlements Program, over 1.5 billion people live in substandard houses without access to electricity, clean drinking water and sanitation facilities. A severe lack of financing along with rising prices of construction materials has made ‘quality housing’ out of reach for a common man.

In India, the 12th five year plan starting in the year 2012 has placed the current rural housing shortage at 40 million houses. In order to meet this huge gap, in the business as usual scenario, the energy intensive construction sector, can play havoc with our natural environment. However, the habitat sector has also been recognized worldwide to have a huge potential to mitigate climate change effects if environment friendly construction practices are adopted on a large scale.

Having recognized this existing gap in affordable housing as an opportunity, a US based firm by the name of World Haus has been building low cost, eco - friendly homes for people in developing countries. A one room 220 square foot house built of interlocked compressed earth-bricks, steel and polystyrene roof panels costs less than INR 100,000. The firm provides solid, weather-tight housing for about half the price of a normal brick-and-mortar home.

Innovative walling and roofing technology using local materials provides protection from extreme weather conditions. Bulk of the materials are assembled on site and the houses can be built in 10 days. Local on-site house construction makes these houses cheap and easy to assemble. A modular building system allows families the flexibility to build any size and configuration they desire. Home owners are also given the option of installing environment friendly amenities like clean burning stoves and solar electricity in the houses.

World Haus is working with mortgage providers to make homes available to the people in monthly installments of around INR 2000 so that more and more people can have access to quality houses. The firm is also setting up partnerships with state governments and NGOs to make houses available to families earning less than Rs. 100 a day through subsidies and rental housing programs.

Local construction, a local dealer network and factory supply chain all serve to stimulate local economies having a positive effect on livelihood generation.

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