UN-Habitat creates sustainable building design charter

Areas such as staircases should be located on the East-West facing walls.

Green or sustainable architecture is gaining momentum in many parts of the world. This has been necessitated by a growing global population that brings with it irreversible changes in the use of natural resources such as land, water and energy.

As a result, UN-Habitat has moved to formulate a charter with 20 action points that if adhered to will see great strides made in the way we design buildings in tropical areas.

Here, we sample the first five targets and what they portend for current and future buildings:

• Site analysis – For an existing structure, this includes a need to retrofit poorly designed buildings with a view to include newer and more eco-friendly features. About a year before project commencement, there is a need for proper data collection on all climatic conditions pervasive in any given area.

• Building footprint – The area to be covered by the actual structure ought not to be more than 60 per cent of the plot. This gives room for the establishments of plants that enhance the plot’s sustainability.

• Building orientation – The primary purpose of a house is to protect the inhabitants from the vagary of the elements. In view of this, the long axis of a building in the tropics needs to be designed along East-West to mitigate against direct solar penetration. It is helpful to indicate the North direction in building plans.

• Building form – In the tropics where heat and humidity are constant features, design must take into account such climatic conditions. For example, hot and humid regions such as the Kenya coast need a narrow house plan that maximizes natural light, cross ventilation and minimizes heat gain. Our hot and arid areas such as require compact forms of design that may include a courtyard to retain cooler air and minimize heat gain.

• Space allocation within the building – Building services such as toilets, staircases, lifts and kitchens should be located on the East-West facing walls. In line with the sun’s movement during the day, these service areas will act as buffer zones against heat gain into the ‘active’ portions of the building. In addition, these areas will benefit from the natural lighting thus reducing overall electricity consumption.