Trends in Sustainable Housing

There has been large-scale proliferation in construction of buildings worldwide due to population growth, economic development, urbanization and migration. According to UN Habitat, there has been a migration of the world's population from rural areas to cities or smaller urban areas. In fact, this trend is expected to continue and cities within the developed as well as developing nations are expected to grow in terms of population. As a result all forms of construction activities are expected to become more intense than ever in the years to come.

Usually the development of urban areas suffers from weak process of planning and control which lead to bad housing conditions, poor sanitation system, limited electricity and water supply, and often poverty.  These issues coupled with high population growth rate, environmental degradation, global warming and limited non-renewable resources highlights the importance of sustainable housing for the survival of humankind.

Sustainability in Buildings

Building construction and operation have extensive direct and indirect impacts on the environment. Buildings use resources such as energy, water and raw materials, generate a variety of wastes and emit potentially harmful gases. Basically the environmental impacts of buildings take place within six stages of building lifecycle:

  • Design process
  • Material or product manufacture
  • Distribution
  • Construction phase
  • Operation
  • Refurbishment or demolition

In terms of energy consumption, 60 percent of the world’s electricity is consumed by residential and commercial building. Space heating accounts for 60 percent of residential energy consumption and water heating for 18 percent in developed countries. Therefore radical changes must be made in design and performance of the buildings to reduce energy consumption and its corresponding environmental impact.

In many countries, sustainable construction methods are being adopted to lead the building industry towards sustainable development and provide better quality living environment. Basically sustainable building design and construction intend to diminish environmental impacts of building over its entire lifetime by paying attention to environmental, socio-economic and cultural issues.

Trends Around the World

The developed and developing world is facing sustainable housing and urbanization challenge in different ways.  Currently industrialized countries are the highest contributor in CO2 emissions. However it is expected that developing countries will take the lead in global warming in the near future. Developing countries are experiencing fast-paced urbanization and at the same time slums and informal settlements are also expanding rapidly which makes development of sustainable housing a difficult proposition.

Countries around the world are taking steps towards implementing sustainable design in the building sector. However most of them are still far from reaching the intended targets.  The major barriers in implementing energy efficiency in the building sector include:

  • Economic and financial issues;
  • Structural characteristics of political, economic and energy system; and
  • Lack of awareness and information

However different countries adopt different approaches for sustainable construction and set different priorities, depending on their economic condition. Nations with high economic growth are developing sustainable buildings making use of latest technologies and innovations. In case of developing countries, social equality and economic sustainability are foremost considerations. In fact, developing countries are moving slowly or even negative towards adopting sustainable housing strategies.

As far as Middle East is concerned, economic considerations dominate for oil and gas-rich GCC countries as they protect their oil and gas export reserves by investing in new ways to boost energy efficiency and lower energy consumption. However for less-affluent countries, such as Jordan, lack of indigenous energy resources and high energy costs are the primary reasons for implementation of sustainable design strategies in buildings.

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Primer on Wood Wool Cement Board

Wood Wool Cement Board (WWCB) is a versatile building material made from wood wool and cement where each fiber is coated with a thin film of Ordinary Portland Cement (OPC) that, when cured, partly petrifies the wood. In that way the fiber will last indefinitely as long as the cement film is not damaged.

Environmentally speaking, cement has a negative CO2 signature and therefore both the wood and cement, when decomposed, are harmless to nature and as a result all homogeneous WWCB products have green labels in Europe. It combines the advantages of both wood and concrete together: as light as wood, as firm as concrete. Sound absorption, shock resistance, fire proof, moisture proof, mildew proof, all these functions are provided. It can widely be applied to gym, theatre, meeting room, factory, school, library, swimming hall etc.

 

Versatile and Durable

WWCB has been in use in Europe and other regions for a long time now. The worldwide acceptance of Wood Wool Cement Board proves its versatility and, not least important, its durability in any climatic conditions. The salient features of WWCB are as follows:

  • Fire resistance
  • Wet and dry rot resistance
  • Termite and vermin resistance
  • Thermal insulation
  • Acoustic performance – sound absorption
  • Excellent heat buffering capacity
  • Light weight to handle
  • Easy to process in construction
  • Relative low energy consumption to produce
  • Limited impact on local natural resources
  • No waste product at end-of-life cycle;

 

Important Considerations

WWCB can be produced in densities ranging from 280 kg/m3 up to 1400 kg/m3. This allows for a wide range of applications depending on the required properties of the product. Low density material is used for insulation of sound and temperature, medium density material is applied more structural as the higher density also gives higher bending strength than the low density material. In situations where one needs the qualities of the low density material for walls, the structural strength of the building has to come from reinforced concrete, steel or wood framing. The medium density boards have specific applications that make it a fire and vermin/termite resistant competitor to conventional boards currently used in stick build construction.

To differentiate between low density WWCB and medium density boards, the medium density boards are promoted as Wood Strand Cement Board WSCB as the 25cm (10") long wood fibers in WSCB give it substantially more structural strength than the cement bonded (short) fiber boards currently in the market. WSCB can also be seen as the lighter and stronger replacement of Cement Bonded Particle Board (CBPB). Due to the relative high OPC content, WSCB is heavier than Oriented Strand Board (OSB), but has none of the disadvantages of OSB type products. Types of wood that are suitable are species of pine, poplar/aspen and eucalyptus. Other wood species are sometimes suitable or can be made suitable by cement mixes that counter wood elements that obstruct curing.

Both WSCB and the Large WWC prefab wall elements are relatively new developments. WSCB being a patented medium density board from a Dutch WWCB machine builder while the large elements are a development of a Swedish customer of the Dutch company. The latter has also developed a pole reinforced low density building board (240x60x10-15cm) that shows high potential for affordable, well insulated social housing anywhere in the world.

Depending on the construction and local conditions it is now possible to build all types of well insulated housing with WWCB from 3.5 cm thick for moderate climates to walls up to 60 cm thick for extreme cold or hot climates. Especially the use of the thicker low density WWCB material results in very substantial reduction of energy cost for air conditioning and/or heating while the indoor living climate is strongly improved because these walls are breathing. They absorb heat and moisture and release it gradually over a 24-hour period

 

Potential in the Middle East

For construction industrsy in the Middle East, especially residential, wood wool cement board can provide comfortable living conditions in homes that require less cooling equipment than conventional homes. It can be implemented in all kinds of building concepts (new and renovation) without major hassles. In combination with concrete it can form well-insulated walls that can replace ceramic bricks.

A modern WWCB plant can produce over 300 different products in one location reducing commercial risk normally experienced with production of new materials. Considering the potential for all kinds of residential housing in the Middle East, wood wool cement board is an attractive business proposition for cement producers and cement converters in the region, and can also provide ‘green’ low-cost housing solutions. To sum up, WWCB can be a useful tool to provide sustainable housing which may help in rejuvenating the green building industry in the Middle East