Construction in Yemen and sustainable development: Are they sustainable? [Archives:2008/1123/Reportage]
By: Dr. Basel Sultan
Sustainable development refers to fulfilling human needs through simultaneous socioeconomic and technological progress and conservation of the earth's natural systems. Sustainable world progress depends upon continued economic, social, cultural and technological progress. The construction industry together with those construction material production industries supporting it are significant contributors to both the local and the global economy's current unsustainable development path and major exploiters of local and global natural resources. Therefore, as indicated by the United Nations “Agenda 21,” the industry's development isn't a local issue, but has become an international one.
The Agenda 21 for Sustainable Construction in Developing Countries urges introducing sustainable construction development into the developing world for two main reasons: First, the developing world still is under construction and every minute means that, in all likelihood, constructing a building, road or dam won't support sustainable development principles. Second, pressures on resources in these countries means they can't afford to make mistakes and must ensure that what's being constructed now will be sustainable economically.
Sustainable construction is seen as a way for the building industry to achieve sustainable development and is described by the European Union as the set of processes by which a profitable and competitive industry delivers built assets (building structures, supporting infrastructure and their immediate surroundings), which:
– Improve quality of life and offer customer satisfaction
– Offer flexibility catering to user changes in the future
– Provide and support desirable natural and social environments
– Maximize efficient resource usage while minimizing waste
– Minimize energy consumption throughout production and a building's life cycle
The construction industry's key contribution to economic sustainability can be seen in:
– Ensuring financial affordability for the intended beneficiaries
– Ensuring cost reduction by improving efficiency
– Ensuring sustained and efficient usage and reduction of resources and materials
– Ensuring reduced energy and raw materials input
– Ensuring sustained employment opportunities through materials production and distribution
Most of the abovementioned issues are lacking in most developing nations' construction industries, including Yemen, which historically has established a unique heritage of traditional construction and urban environment. Up until a few years ago, traditional Yemeni buildings successfully sustained and survived virtually unchanged over the centuries.
Yemenis efficiently utilized only locally-available materials and resources to create such buildings, which are well adjusted to the hardships of that country's varied climatic regions.
However, the low productivity regarding such traditional buildings and Yemen's urgent need for infrastructure and housing projects, along with the emerging trend toward modernization, has caused an ongoing and hasty shift from the traditional to the modern and modern/traditional building types.
Such modern buildings mostly depend on inefficiently implemented imported technologies and materials and, as previously pointed out, excessive construction waste associated with the construction activities of these modern/traditional buildings.
What have increased the industry's problems are poor and inadequate architectural and structural designs not in accord with local needs or priorities nor adapting to local conditions and resources. Practically, less costly modern buildings typically are achieved by lowering quality, thereby creating less durable, less attractive and less sustainable buildings and constructed environments.
Traditional Yemeni construction and materials
Traditional Yemeni construction is characterized by using local materials and implementing indigenous methods and techniques. The merits of this traditional model in the construction industry are many, with their designs meeting the needs of the environment without violating it. In mountainous areas, homes built of stone and brick or mud walls with thicknesses of 50 cm. and over afford excellent thermal insulation qualities, whereas the traditional materials for traditional buildings in Yemen's hot and humid coastal areas are sun-dried or burnt clay and mud bricks.
Traditional Yemeni buildings in mountainous areas.
Traditional walling materials and buildings of clay and mud bricks currently aren't in wide use in most parts of Yemen and their construction has decreased – not only in urban areas but in rural areas as well – thus indicating the greater desirability of cement buildings, lack of interest by designers and clients and public ignorance concerning local materials.
Other reasons are that mud homes are considered unattractive, subject to water penetration, unsound and may not be structurally durable if not well constructed. Furthermore, limited quantities, extremely poor quality and high costs hinder the widespread use of local materials.
Traditional Yemeni buildings may not be structurally durable.
Modern Yemeni construction and materials
Modern construction refers to those buildings recently constructed in Yemen, mostly in cities and towns. Construction in these urban areas frequently is done using modern techniques, mainly characterized by a reinforced concrete structural frame, while exterior walls are constructed of cement blocks or local stones simulating the traditional style in a type of blended modern/traditional.
In mountainous areas, buildings designed and constructed using modern techniques, wherein exterior walls are made of only cement blocks and typically plastered inside and out with cement plaster, are unsuitable for Yemen's climatic conditions. Additionally, their design ignores regional environmental conditions. Such reinforced concrete buildings with concrete block exterior walls provide insufficient thermal inertia; thus, climatic protections are inadequate and comfort is minimal because they are warm during the day and cold at night, thus requiring artificial heating. Moreover, stresses caused by extreme temperature differences rapidly deteriorate such structures' construction, as well as their appearance.
Modern buildings of the same design, i.e., those with cement block exterior walls, that are constructed in Yemen's hot and humid coastal climate offer very little thermal comfort. They are hot during the day and uncomfortably warm at night, so artificial cooling is required continuously. Furthermore, concrete reinforcement and plaster quickly disintegrate in the humidity and salinity of such climate's air, hence, continuous essential maintenance is costly.
Cement plaster disintegration of modern buildings in Yemen's coastal areas.
However, external stone wall cladding added to the modern reinforced concrete frame's structure, despite being over-designed and over-constructed, and hence, excessively expensive and unaffordable, nevertheless afford a comfortable indoor climate both day and night without need of artificial heating or cooling. Long-term savings in energy, maintenance and a comfortable indoor living environment can outweigh the initially high cost of stone walls.
Modern/traditional buildings and excessive use of materials.
Modern/traditional buildings are rigid toward future changes and recycling.
Assessment
Yemen has a long tradition of construction and materials that can have more sustainable character and better suited to local conditions than that introduced by imported technologies. But due to the low construction productivity, stability and high cost in the traditional buildings; together with the urgent need for infrastructures and housing projects, it was necessary to use modern practices and materials, but this was done in a hasty and chaotic way, creating inefficient and wasteful industry, and led to the over reliance on high energy materials. In addition what has increased the problem is the incapability of the construction industry neither to control nor to recognize the faults within the modern construction process and activities. In assessing the local construction and material industries of Yemen, the main factors that have generated the current inefficient and unsustainable building and design practices, in the modern/traditional buildings, can be suggested as the unclear and chaotic construction and design practices. The add-on of unnecessary structural elements with the absent of supervision has lead to the inefficient utilization and excessive waste of high energy structural materials such as steel and Portland cement. The situation is persistent due to the absence of local standards, specifications and Lack of construction regulations moreover due to the lack of studies to evaluate the necessary domestic requirements for the main structural materials such as cement and steel, and ways to lessen or substitute their use.
The unreliable and untrustworthy professional services and assistance, in the design and construction practices, together with the inefficient and corrupted authority control over inadequate design and construction activities, and the non-transparent and costly
process for obtaining permissions; has all increased informal activities. The widespread drift to exclude professional services and the reliance on informal or self-help has only led to implementing costly over-designed practices, especially in the structural elements. Moreover, in an attempt to reduce cost has caused a general tendency to use low quality and less durable finishing works.
There are general Inefficiency and randomness in the allocation of local resources, e.g. inefficient production, distribution and utilization of stones; which has caused needless high increase in energy consumption, in the extraction, transportation and the on-site stone cutting and craftsmen activities, together, with the non-existence of reuse mechanism , and cost reduction approaches.
In view of the above difficulties, and with the broad absence of clear future vision and lack of knowledge to how the industry should be, it will not be likely to apprehend sustainable technologies and sustainable development requirements. it can be difficult to achieve sustainable construction through efficient and affordable techniques, Unless the local industry, with its traditional heritage, realise the different ways of defining and meeting this goal at a local level, thus actions have to grow from local initiatives, making use of local strengths and addressing local barriers. Actions that can help in achieving Sustainable Construction development are by Initially unravel the problems associated with the current industry; Increase awareness of the industry to the new issues and requirements of sustainable construction and designs. Also the education syllabus and the media should increase the perception and awareness of engineers so they can achieve cost reduction through efficiency improvements and material inputs moreover achieve energy efficient designs. The authorities should strengthen their control through legal practices and appropriate construction practices, clear building technologies, standards and regulations. This can start off through human development, which is needed to control and to monitor any required development. All the participants in the local industry (government, private sector and academic) should set up enhanced construction methods and designs that can effectively make use of low energy local materials. Additionally, the industry should essentially and effectively develop appropriate building models that embrace economic, social, cultural, and technological sustainable progress. Finally and most importantly the industry should establish 'Local Agenda' and local sustainable strategies and policies and ways in implementing them.
Dr. Basel Sultan, Sana'a University
Faculty of Engineering, Civil Engineering Dept.
[email protected]
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[archive-e:1123-v:15-y:2008-d:2008-01-24-p:report]
