Dissertation Report : Materials and techniques in Low Cost Housing
Submitted By: Nitish Sharma B.Arch 4th Yr. E.No. : 071021
List of Contents: Introduction Ÿ Definition of Low cost Housing Ÿ Need of Low Cost Housing in India Ÿ Types of Building Materials Ÿ Materials in low cost Housing Ÿ Mud Ÿ Brick Work -Bonding -Lintels -Brick Jali Ÿ Form and Requirements of Material Ÿ Furniture and Other Materials Ÿ
"No innovative artist can hope to proceed in work without having gained an understanding of the local wisdom of a place.” Laurie Baker Introduction: Low Cost Housing is a new concept which deals with effective budgeting and following of techniques which help in reducing the cost construction through the use of locally available materials along with improved skills and technology without sacrificing the strength, performance and life of the structure. There is huge misconception that low cost housing is suitable for only sub standard works and they are constructed by utilizing cheap building materials of low quality.The fact is that Low cost housing is done by proper management of resources.Economy is also achieved by postponing finishing works or implementing them in phases. Low Cost Housing : A concept that deals with : Effective Budgeting Techniques Which Help in reducing the cost of Building Use of Locally available materials
Need of Low cost Housing in India: With the country having millions of homeless families, it is imperative that what money is available must be used ONLY for essentials, and none of it for fancy frills! Laurie Baker The population of homeless people is increased. It is estimated that more than 70 per cent of the shortage of dwelling units are for middle and low income brackets.
Materials involved in Low Cost Housing: The building construction cost can be divided into two parts namely: Building material cost : 65 to 70 % Now in low cost housing, building material cost is less because we make use of the locally available materials and also the labour cost can be reduced by properly making the time schedule of our work. Cost of reduction is achieved by selection of more efficient material or by an improved design.
TYPES OF BUILDING MATERIALS The various building materials available can be divided into two types and they are: Traditional materials These materials serve the basic needs of the majority of the population. These have very useful properties, however, there is a scope to modify these through appropriate changes in the process of production as well as in the techniques of application, so that these are made structurally and functionally acceptable. Conventional materials The conventional materials are those, which have been obtained by using the modern technologies and can be mentioned as fruit of research and adopted to indigenous requirements. Mud as a Low cost material : Mud is the most readily and cheaply available material found almost everywhere.
Improvement of Mud During post earthquake reconstruction, mud houses are most effective since they are environmental friendly, cool in summer and warm in winter. Mud is only a material available everywhere in abundance free of cost and is being used as building material from centuries. But such types of houses are temporary in nature, prone to erosion by heavy rains. The disadvantages of mud can be overcome by suitable improvement in design and construction techniques. Stabilization The strength of mud is improved by adding cement, lime, bitumen or fibers and it also becomes resistant to water, its main enemy. Cement stabilized mud blocks, using 3 to 10% cement by weight molded in mechanical machines are better than adobe mud bricks.
Techniques to use Mud
Non-erodable mud plaster Central Building Research Institute, India has developed an economical but effective process to protect mud walls by applying non-erodable mud plaster. Non-erodable mud is prepared by mixing bitumen cutback (Bitumen & Kerosene oil mixture) with a specified mud plaster. Soil should consist of clay 20-25%, sand 40-45% and remaining part may be silt, peat, loam etc, but it should be free from organic matter. Bitumen of 80/100 grade penetration and kerosene oil are mixed in the proportion of 5:1 (by weight) for preparing cutback. 64 kg of cutback is required for one cubic metre of soil. Non-erodable mud plastered walls are resistant to water erosion. Terra-cotta skin to mud walls Center for Science for Villages, Wardha, India has developed technique of providing potter made tile lining to mud-walls protecting them from rain and moisture. In place of potter made tiles, Kiln-fired brick or tiles may also be used to protect mud walls from rains. These tiles/bricks can be fixed with mud mortar & pointed with cement mortar.
Improved Thatch Roof An effective treatment for rendering the thatch roof fire resistant and water repellent has been evolved by Central Building Research Institute. It involves plastering of thatch layers by the specified mud plasters. Top & bottom of the thatch roof is plastered with nonerodable mud plaster, which makes it durable & fire resistant too.
Brickwork
LINTELS A lot of unnecessary steel and cement concrete is used for lintels. Instead, place one row of bricks on the edge over the frame (or space) and then above the, one on each side, a row of more bricks on edge. The space between these upper two rows of bricks is then filled with concrete in which a small steel rod is placed. The only weight the lintel is eventually carrying is a small triangle of brickwork. all other weight of walls, floors etc above are carried by the wall at the sides of the opening.
The usual round and segmental arches need shuttering or support during construction. The corbel arch needs no support and is extremely simple and easy to make. one quarter of a brick is extended out from the brick below it. The writer successfully used such ‘arches’ over openings up to 5 meters wide.
RAT TRAP BOND: The RAT TRAP BOND is still mainly unknown in India,though used in England for the past several hundred years. It is as strong as the other bonds but uses 25% LESS bricks and mortar. Thermal insulation is very much better.
BRICK JALI : ‘Jali’ - formerly pierced stone panels – is one of India’s oldest methods of letting into a building filtered light and ventilation but maintaining privacy and security.
BRICK JALI can function in the same way – either as panels or as a complete load bearing wall.
The production of cement and steel: Enormous amount of energy (fuel) and Cause a lot of air pollution. Also mountains of ugly useless waste material is dumped all round the factories. Production is costly and India is short of energy.
MORTARS Cement and Sand
Lime and Sand
Lime Cement
Sets quickly but cement is expensive
Set slowly but very strong, can be used with any type of Brickwork
Takes Equal time to settle as cement.
Form and Requirements of Material
Furniture:
Other Materials:
Clay Flyash Burnt Bricks : • • • •
These are produced from flyash and clay Are stronger than conventional clay bricks. These consume less energy, provide better thermal insulation and Solve the problem of disposal of waste material flyash & thus are environmental friendly.
Ferro-Cement • •
Ferro-cement is a thin walled versatile high strength cement based composite material made of cement mortar reinforced with one or more layers of wire mesh closely bound together to create a stiff structure unit with high performance.
Conclusion : We have techniques and materials which are low cost but are not workable because of strength . So addition of new techniques and materials is required to make them workable.
References : Ÿ Ÿ Ÿ
“COSTCUTTER” By Laurie Baker
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“MUD” By Laurie Baker
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‘HOUSES’ By Laurie Baker
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‘RUBBISH BAKER ‘ By Laurie Baker
