«CSAAR (7: 2010: Amman) Sustainable Architecture and Urban Development \ Edited by Steffen Lehmann, Husam Al Waer, Jamal AI-Qawasmi. Amman: The Center ...»
Rilling, 0., & AI- Shalabi, A. On optimized energy consumption and reduced C02, Emissions of Building in SoutheastAsia by help of thermal simulation, IETBIC' s 08 The 1st International Conference of Institution of Engineering and Technology (lET) Brunei Darussalam Network, Brunei Darussalam.
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Rumana Rashid, Mohd. Hamdan Bin Ahmed (2010) "The Comparison between The Thermal Performance of a Contemporary House and Traditional House in the Dense Dhaka City in Bangladesh."A field study was conducted at Dhaka city in Bangladesh. Conference on Teclmology and Sustainability in fhe Built Environment. Riyadh, KSA 3-6 Jan, 2010 Rumana Rashid, Mohd.Hamdan Bin Ahmad, 'Thermal Performance of Bangladesh Traditional House During winter and summer season'
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The Sustainable Architectural Principle of Traditional Bamboo Houses in Bangladesh Md. Sayem khan, Ruman Rashid University Technology Malaysia (UTM), Malaysia Abstract Bamboo is one of the strongest woody plants on planet. Bamboo is usually grown on village homesteads. The use of bamboo in traditional house construction is 100% environment-friendly, can mean a lot of savings in material used and transport. The tradition al Bamboo houses are not the product of any theory design, but influence of instinct, intuition, common sense and communal memory. This research takes the steps towards such an understanding by analyzing some field study on several numbers of bamboo houses, as case studies of the signiticant features of traditional bamboo houses, which make it more durable. Cheap and natural light weight material, aesthetically appealing design, attic space for thennal comfort, proper cross ventilation and renewable eonstruction system of the Bangladesh traditional bamhoo house makes it more sustainable in wann humid tropieal climate in Bangladesh. The bamboo house fonn has been defined by c1imate, site, and purpose, available materials, building technology, historieal experience and world view. The best material to build a house wills detinitely the loeal material. By applying the unlimited teehnology nowadays on the gift of the Allah- Bamboo, this natural bamboo as a raw material have a very high potential to become the best eonstruetion material in future for sustainable development in the Bangladesh.
Bamboo is one of the strongest woody plants on planet. Its fibres are about 10 times as strong as the wood fibres used today. Bamboo is usually grown on village homesteads. The use ofbamboo in traditional house construction is 100% environment-friendly, can mean a lot of savings in material used and transport.
The traditional Bamboo houses are not the product of any theory design, but influence of instinct, intuition, common sense and communal memory.
Traditional houses are located vastly in rural areas with its naturallandscape.
The context of Bangladesh traditional bamboo house is a natural projection of the regional imagination. Traditional House local context have its own reality and existence independent of others imagination of traditional viJlage in Bangladesh. Traditional house is designed by the owner and based on low investment, local materials, combined with the assistance of relations, friends and neighbours (Rumana, 2009). It reflects cultural heritage of peoples and also encapsulate traditional tDrms values and symbolic images of nature. Landscape painters collectively crated the village as aland of dream, a place for passion and sensuality (Bermingham, 1986). Architectural and cultural movement evolved in the late 19TH and early 20 TH century such as modernism, rejected traditional forms of art, literature, religious faith, social organization and daily life (Kolokotroni, 1998).This paper presents the structure, construction, design concept, arrangement, important feature and thermal performance of the tradition al bamboo house to justify the sustainability. Thermal performance of traditional bamboo house confirms the hypothesis about their environmental sustainability.
Climate of Bangladesh
In terms of ecological region or biomes described by UNESCO (United Nations Educational, Scientific and cultural Organisation) (Lean 1990) Bangladesh, lying between 20°34' N to 26°33' N and 88° OI'E to 92° 41 'E. is in the Indo-Malayan Realm. The climate of Bangladesh based on the widely used classification by Atkinson (Koenigsberger, 1973). Climatic variables are shown in table 1,
3 Structure of Bamboo House Bamboo is an easily growing organic material for houses of Bangladesh. So bamboo is a popular material all over the country.
3.1 Plinth or noor Cement stabilized earthen plinths are used in bamboo houses. Occasionally, the houses are built with elevated bamboo frameworks and bamboo mats as plinths.
In some flood-prone areas, houses have a built-in wooden! bamboo platforrn (machan) norrnally used as storage space, but during flood serves as a raised refuge area. This practice should be encouraged and promoted for wider Md. Sayem khan & Ruman Rashid replication. Stabilization of the typical earthen plinth can be carried out with a mixture of earth and cement. The proportion of cement to be added depends on the nature ofthe soil, which can easily be tested on site. Capping the plinth with cement-stabilized earth is cheaper, easier to construct and maintain. Complete stabilized earth plinth is more expensive and harder to construct, but the results are more durable.
Typically bamboo houses have bamboo mat walls with bamboo or timber posts.
Also organic materials Iike jute sticks, catkin grass are used. Flood with strong currents can destroy wall panels, get washed away and may be partially or complete lost, especially ifthe connections to posts are weak.
Figure 2: Frame work ofthe bamboo house and entry way to upper space.
Local treatment of the bamboo mat walls is done by bituminous, oil etc. Simple chemical preservative treatment methods (dip diffusion method, intemodal injection method or hot and cold method) for increasing the longevity of organic materials have been developed a long time ago. Cost can increase but can increase longevity by more than three or four times. Untreated, bamboo mat walls do not last more than 4-5 years in outdoor conditions, but after treatment lasts for 15-20 years (ADPC, 2005).
3.2.1 Chemical Treatment ofBamboo Mat Walls Simple chemical preservative treatment methods for increasing the longevity of organic materials have been developed a long time ago.
Sustainable Architecture and Urban Development 265 Increases cost by 20-25%, but can increase longevity by more than three or four times. Ifuntreated, bamboo mat walls do not last more than 4-5 years in outdoor conditions, but after treatment lasts for 15-20 years. The chemicals are not hannful if proper precautions are maintained. For chemical preservative treatment of bamboo battens and mats, the simplest method is to build a tank made of bricks and concrete, or at cheaper cost, lining an excavation in the ground with polythene sheet, or cutting a cylindrical metal container (e.g.. oil drum) into half and welding them end-to-end.
A typical preservative can be prepared to be mixed in the tank in the following proportions: Copper Sulphate 4%, Sodium Dichrornate 4%, Boric Acid 2%, Water 90% = TOTAL 100%. ( during chemical treatment safety precaution also taken for the working people). After treatment when the bamboo is dry then it is ready for use. The materials should preferably be freshly harvested, but dry ones can also be treated.
Bamboo battens and mats are to be first soaked in water for at least 24 hours and then dried. They are then to be immersed completely in the chemical preservative solution for 24 hours. After soaking, the materials are to be raised above the tank and supported on bamboo poles or timber battens so that excess chemicals can drip back into the tank and can be re-used. Then they are to be dried in an open shaded space for 1-2 days and then in sunshine for 3-4 days.
Gloves or polythene bag covers to be wom to protect hands from chemicals during the treatment process (ADPC, 2005).
Md. Sayem khan & Ruman Rashid Figure 3: 'Cross bracing' - Structural frame work ofthe bamboo house.
3.3 Roof Typically, roofs in bamboo houses are made from eatkin grass, riee wheat or maize straws with usually bamboo and sometimes reed stalk framings.
Thatehing materials can get detaehed and wash away. Secondary hazards otlen connected to flood are heavy rainfall, which can cause damage. Strong winds can also blow away thatching materials and damage frames. So in some regions c.I. sheet are also used for roofs.
To increase stability and wind- resistance of the structural frame of bamboo framed houses, cross bracing with split bamboo sections should be done. If a house becomes weakened at its base due to flood, cross bracing helps to keep the structure stable. Split bamboo sections used for cross bracing should be treated with chemical preservatives so that they do not decay easily and lose their strength. Instead of jute or coir rope, nylon rope or good quality galvanized wire should be used for tying the elements ofthe structural fl·ame.
3.4 Upper space Upper space ceiling is used as storage; it should allow ventilation and should be accessible for maintenance. Adequate number and size of perforated bamboo mat walls should be built oriented along thc prevailing wind flow direction to Sustainable Architecture and Urban Development 267 allow cross ventilation. Extended roof eaves are to be used to prevent direct ofwalls rain.
Figure 4: Upper space ventilation ofbamboo house and wall gap from floor Rainwater gutters can be used to discharge water away from the house while collecting arsenic-tree rainwater. Houses should be built house on raised homestead with slightly sloping ground for drainage.
4 Bamboo Supply Although being a vital resource tor house construction, bamboo has become searee in many areas with a resulting inerease in priee. Inadequate disease prevention and mismanagement of existing resources eontribute further to dec1ine in stock. There is thus the need for regeneration of bamboo supply through improved cultivation and management. There are many afforestation and soeial forestry programs in Bangladesh, but none panicularly address bamboo cultivation. There is also potential for introdueing hazard-free bamboo treatment as a sustainable process for the utilisation and consumption of the resource within the framework of a wider initiative for its improved and sustainable regeneration, production and management. Various livelihoods are Iinked to bamboo and an initiative tor bamboo regeneration would also regenerate these livelihoods.
5 Bamboo Farming for supplying traditional house material
Bamboo farms should be established to demonstrate the potential of improved sustainable bamboo production and to address the environmental implications of the decline of this Ioeal resource. Improved bamboo propagation and cultivation methods have been developed by Bangladesh Forest Research Institute (BFRI) and bamboo farms would allow extend these methods, other than improved
bamboo famling, some of the main activities of the farm should be:
268 Md. Sayem khan & Ruman Rashid
-Further research and development of bamboo cultivation and propagation methods.
-Bamboo treatment with adequate safety measures.
-Production and marketing of treated bamboo building products, furniture, household and agricultural implements and handicratls.
Figure 5: Bamboo Farming