By Ian Ferguson

There are a few fundamental truths about going green. If you are not prepared to live in a cave or a mud hut, bathe in a stream, as well as grow your own veggies and raise cute little feathery, furry things that you will later kill for dinner, there has to be a major paradigm shift in your current thinking and an acceptance of compromise.

So if your idea of ‘going green ‘ is to change all the light bulbs in your house to low watt low energy, well done, but read on as there is a bit more to it than that.

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Green building is the practice of increasing the efficiency of buildings and their use of energy, water, and materials, and reducing building impacts on human health and the environment through better siting, design, construction operation, maintenance and removal - the complete building life cycle.

Where do we begin? Let’s take the first idea of living in a cave or a mud hut and apply those principles to our modern lifestyle requirements.

Believe it or not there are many communities around the word who still live in caves. The cave homes of Spain’s Grenada province have been around for hundreds of years. If you don’t believe me visit the website www.cavehomes.com. You can pick up a 1000m² plot of land near all amenities for €97200. One catch - it needs restoring. Today’s cave homes come fully equipped with mains water and electricity, sewerage and even satellite TV and broadband internet connections.

Caves are ecologically friendly and are arguably the most ecologically sensitive form of construction. They maintain a constant indoor temperature through thermal mass. They do not require large amounts of inputs in terms of manmade materials such as bricks concrete, mortar or metal and do not demand costly synthetic or ecologically questionable construction materials. Costs are kept to a minimum, there is little construction waste and they can be expanded as the family grows. It might be back breaking work but I am sure it is very rewarding…

The compromise reached with a cave house is that in nearly all cases the front façade is constructed in a conventional manner. To the casual observer they look no different than a local villa. They have not been built with materials that have been shipped halfway round the world using large amounts of energy in the process, just a few bricks and some terracotta tiles. Plus all mod cons of course.

We cannot all find caves to live in but, we can, and should, apply the principles of sustainable living architecture to our houses of the future and where possible our existing homes.

Location determines the climatic conditions in which the house will be connected to the environment and what modifications to the surroundings (adding or removing vegetation or water for example) may be necessary. Orientation is the first key element in building. Here in the southern hemisphere it is important that the building faces north so that we can capture as much solar energy as possible while shading will be used to avoid the harsh summer sun. We will discuss prevailing wind direction and other climatic influences later.

The shape of the house has a lot to do with its thermal efficiency. The amount of contact area between the house and the outside will influence what amount of heat is gained or lost. The influences of the dwelling having a high roof, broad expanses of glass, internal courtyards and the like, need to be considered.

The second key element therefore, is size. The smaller the exposed area the better. The ideal shape is a long, compact rectangular house that is set on an east west axis. We mentioned compromise earlier and this is where it begins, as local conditions may not allow the perfect positioning of the structure. The perfect solution would be to half bury the southern aspect of the house and make use of solar lighting tubes for room lighting.

The problem with a lot of local authorities and the so called aesthetics committees in housing estates is that they insist on outdated and subjective design criteria, such as the rule of no solar heating panels in Eagle Canyon golf estate near Johannesburg, and everything must be faux Tuscan.

In order to be efficient, the building must be designed in such a way that it captures and releases heat when and if necessary. Dying of the heat in summer is not an example of good green design. The use of thermal mass in the design is critical, particularly in the construction of floors, ceilings and walls. Thermal mass must not only retain heat for winter warming - it must, by way of convection, also assist in summer cooling.

As the earth’s resources become scarce, it is becoming important to engage with nature and to re-assess the ways that we use both energy and material resources. As mentioned earlier we do not need to build from materials that have been shipped halfway round the world when, if we took the trouble, we could find locally grown and produced materials that could do the job just as well, if not better. It also makes sense to use natural materials that do not rely on high energy processing.

The third element in our quest for green then, is the source of construction materials:

The use of natural paints, stains and waxes may be safer to apply and more beautiful to live with than many of the proprietary brands we use without question, when price is the only criteria. Second hand materials can be sourced near all major areas as we continue to destroy much of our past to make way for the future. They come with a patina that only age can give them and in many cases, a bit of history if you know the source. I have a beautiful wrought iron panel that was once part of Johannesburg’s Mayoral Chambers before it was demolished for the present city hall.

The use of alternative construction material has to be a vital consideration. Most builders today want materials that require limited labour content and are cheap. Little or no consideration is given to its environmental properties.

So here are a few alternatives that have either stood the test of time or are making a comeback. The list is not in any order or in any way limited to the examples given. There are numerous web sites that are far more comprehensive and detailed than this article. If going green appeals to you, explore them further. It’s wonderful what people around the world are doing to try and save this planet.

Straw bales stacked one on top of the other within a wooden lath framework has become part of the shift back to more time tested traditional methods of building. They produce a warm, tactile building with soft rounded edges. The modern equivalent is the use of moulded polystyrene, Lego-like, hollow blocks that use concrete as a filler and structural medium. There is a small housing estate in Heidelberg being built in this manner.

Rammed earth and the use of old tyres as moulds have been used in a holiday home in East London. This development was partially built into a sand dune and has all the thermal mass it could need. I also believe that it was approved by the local authorities and purchasers are able to raise a bond on the properties.

Timber homes built from entire logs is another method of building that utilises the principles of thermal mass and renewable and recyclable material resources. We have all seen the homes in cowboy movies and in Aspen, Colorado; all homes are constructed this way. And man, does it get cold in Aspen.

The indigenous architects and builders of Africa have been using the wattle and daub method of building for centuries. This is a method of construction using a framework of sticks woven together to form a hurdle. Two of these are then placed together with a cavity between which is then filled with stones and small rocks. This is subsequently plastered with mud and forms a perfect wall with that all important high thermal mass. A simple coat of whitewash will ensure it is waterproof.

There is a home in Linbro Park, Johannesburg, currently being built using a similar method known as cob. Straw is added to the mud to add strength. Again, the method produces soft flowing lines and if you have ever seen Anne Hathaway’s cottage in Stratford-on-Avon, you will understand exactly what beautiful textures and profiles the method allows. The vast majority of rural homes are built in these ways throughout Africa.

Thatching forms the ideal roofing material but you can, if you are very progressive, develop a roof garden. It means additional structural cost but you will save on heating and cooling expenses. Approximately 30% of flat roofed commercial and residential buildings in Germany are now constructed with a roof garden.

Externally the use of gravel for driveways reduces the need for brick, while it also provides a low, non-reflective thermal mass, thus reducing further heat gain to the residence. It’s also much cheaper than brick and can give a Zen like appearance to the house.

Heating is relatively simple in South Africa. You just let the sun shine in. Storing it is also fairly simple. As we have emphasised throughout this article you need to store it in a large block of “thermal mass”. A thick wall, floor or ceiling will do the job. Retaining the heat before it can escape is the secret. Our mud hut example has one small window and a door that closes at night, thus trapping the warmth. To optimise our latent heat source, we have to make sure that the house is sufficiently well insulated and draught proof to optimise the day’s gains. There is nothing worse than sitting in a draught. Double glazing is one solution, but it will also prevent the capture of heat, so once again we need to compromise. Rather make use of eaves that allow the winter sun in, but prevent the harsh rays of summer heating up the lounge and bedroom floor when the sun is higher in the sky.

Once you know in which direction the winds blow, you can also determine where to situate breeze ways for natural ventilation during summer and for wind breaks during winter. There’s nothing better than a stoep that catches those long winter rays and is shielded from those cold breezes. It’s a bit like sitting in your car in winter, you get that lizard feeling.

Protection against summer radiation is a must. The use of awnings and covered trellis with the use of grape vines help shield the walls and windows. Internally, curtains and blinds can be used to good effect. Houses can also be designed with al-kashteel wind towers. These are open in all directions so that breezes are forced down into the room and out again. Anyone visiting Dubai can see some wonderful examples of these towers in the old town section next to the creek, and Dubai can reach the mid 40°C.

Nina Maritz an architect in Namibia is using a traditional farm cooler system in the design of the Habitat Research and Design Centre in Windhoek. This system is made of a cavity wall of offset bricks allowing wind to pass through. The cavity is lined with wire mesh and filled with lumps of charcoal. Water is then slowly dripped along the top, wetting the charcoal enough to create evaporative cooling as the air moves through the wall. Farmers used this type of construction to store meat in the days before refrigeration. In fact some early Victorian ice boxes were made in a similar way.

Nothing on the scale of Australia, Canada, Germany, India, New Zealand, U.K. and the U.S.A exists regarding the standards of energy efficient buildings in South Africa. Our motivation has to be a personal one in that we believe that we have to engage with nature and to re-asses the ways that we use both energy and material resources, if not for our sakes, but for those who will inherit the green legacy we leave to them.

Sounds a lot better than living in a cave.