Green Building Materials, the New Normal?

The Vuka Valley Learning Centre model uses repurposed shipping containers as accommodation modules

A sustainable building, or ‘green’ building, is the outcome of a design philosophy which focuses on increasing the efficiency of resource use — energy, water and materials — while reducing building impacts on human health and the environment during the building’s lifecycle, through better siting, design, construction, operation, maintenance and removal.

As we grow in awareness and move away from unhealthy and destructive ways of doing things, the quest for truly sustainable lifestyle choices opens up many exciting opportunities for building private dwellings, hotels, lodges, health spas, schools and other commercial structures for both developers and architects, who are finding conscious and beautiful  ways to create more sustainable buildings.
    Green building minimises the environmental damage and consumption of finite resources required to create a building and also takes into account the environmental impact the building will have for the duration of its lifespan and upon disposal. Green builders therefore use natural and local materials as far as possible and engineer durable structures.
    According to Craig Hohls of The Gild Architects: “Sustainability at its core defines a process that generates a surplus in order to ensure its continuation. Only natural systems are able to generate/grow/expand without a cost – be that energy/nutrient/mass. Therefore we must replicate, align and integrate natural influences and resources in every part of the building as well as ourselves to be truly sustainable. The ideal building is made up of as many parts from local resources as possible, configured in a way that they respond to the natural conditions, in order to serve the occupants, site and surrounds, now and until its end, efficiently.”
     Whereas cement, the main ingredient in brick-and-mortar houses, damages and pollutes the environment at every point of its lifespan, earth and plant-based building materials are far gentler on the environment, even actively benefiting environmental and human health. South Africans are familiar with grass as a building material, particularly in the form of thatching, grass huts such as ‘beehives’, reed fencing and wattle-and-daub buildings. Global and local architects and builders are also working anew with other, ancient plants, most notably hemp and bamboo. As public awareness grows and legislation shifts, sustainable homes are becoming a real possibility for ordinary South Africans.

What green materials replace the traditional brick and mortar?

Straw bale building, which utilises a load-bearing timber frame filled with straw bales (made from local grass) and local mud/ clay/ lime/ cement plaster to seal the walls and floor. The roof is thatched. Straw bale buildings are extremely comfortable, as the straw offers excellent thermal mass and sound insulation. Because straw bales can be shaped, they allow for varied and interesting shapes. There are numerous straw bale buildings in South Africa, especially in the Western Cape.

Cobbing also uses straw, but here it is added to clay, which is the primary building material. Cob houses are quite literally sculpted buildings and therefore very individualistic. They are very labour-intensive, slow to build and extremely durable.

Hempcrete promises to be one of the most important building materials in the next decade at least. Made from a mixture of industrial hemp fibres, lime and water, hempcrete is clean, safe and easy to work with and hempcrete houses are well-insulated and clean. Hempcrete can be formed into blocks (to fill a timber frame) or moulded in situ, making it extremely versatile and opening up wonderful design opportunities. The hemp plant benefits the air while it grows, producing a lot of oxygen, sequestering huge amounts of carbon dioxide and even continuing to clean indoor air once it is part of the wall!

   Hemp is incredibly versatile and can be turned into a myriad of products, including fittings, textiles, food, fuel and plastic substitutes. This means that a small hemp farm, apart from creating a hempcrete industry and providing income and building work for residents, can continue to add value long after everyone in the area has a house, thereby supporting local (especially rural) economies in the long term. Various political and economic dynamics in the 20th century removed hemp, which is one of the oldest and most-used plants in human history, from our industrial arena, but legislation is finally shifting to welcome it back. The potential socio-economic and environmental benefits of industrial hemp and hempcrete are phenomenal.

Bamboo is another plant that has much to offer our building industry. It grows (and regrows) incredibly quickly, sequesters masses of carbon dioxide, is incredibly strong and durable when used correctly and also looks beautiful. Like hemp, the plant is highly versatile and bamboo is used to make furniture, flooring, fabric and many household items. Building regulations currently prevent green builders from using bamboo as a structural material, but this is changing as research and education grow.

One way to help the environment while creating integrated shelter for people, is to use repurposed shipping containers. Beautiful homes, business premises and even holiday resorts can be built from old shipping containers, which lend themselves to modular assembly.

Integration is key. One of the many beauties of plant-based materials is that they can literally be grown when required and used in combination, to their respective strengths. Environmental organisations like The Green Net often provide a networking and coordinating function, bringing together homeowners, farmers, architects, engineers and builders for sustainable building projects.

Advantages of using green building materials in SA

There are many good reasons to promote and ‘grow’ the green building industry in South Africa. Apart from addressing broader environmental concerns such as carbon footprint and biodiversity impact, homes built from organic materials such as hemp, bamboo and straw are genuinely healthier, cheaper and more comfortable to live in, with higher air quality and insulation all round. Green building materials provide a low-cost, or even free, way for people to build homes – in fact, small rural communities can potentially become completely self-sufficient if they grow their own food and have a hemp or bamboo cooperative farm and building industry. 

Green building materials bring various qualities of their own. For example, bamboo has great tensile strength, making it ideal for upright supports, as well as almost-unlimited arches and curves; whereas hemp and straw bales can provide thick, solid walls or – thanks to moulded hempcrete – fine curves and any variety of quirky building shapes. Green architects and designers are adept at finding the most sustainable, locally-available materials and planning spaces that maximise natural resources (such as heat, light and water), minimise toxic inputs and find the optimal combination of materials and methods for each project. Knowledge and skills transfer are crucial, and green building practitioners are well placed to ensure broader community benefit by way of training and business collaborations.
     Creating and building with these materials is generally labour-intensive, so the industry can provide a lot of work, including certifiable building skills and qualifications specific to green building. Many of the building methods are similar to traditional South African methods and indigenous knowledge and experience are a valuable resource. At the same time, we have access to international research, experienced practitioners and technical support and are well equipped to produce innovative buildings that are truly futuristic.

Finally, we have great diversity and great creativity within that: A range of climates and landscapes, allowing us easily to grow (or continue to grow) the plants we need for our building industry, from Highveld grasses that need sub-zero winters to sub-tropical bamboo; and diverse and creative people who specialise in ‘making a plan’ and fusing together the best qualities of whatever knowledge and materials are available. South African music, fashion, humour and even food thrive on our diversity, rejoicing in our unique ability to enjoy fusion and we see many of these elements in our landscape already. Legislative considerations and municipal bylaws require consideration as they still challenge the use of materials that deviate from the traditional brick and mortar. The good news is that the position around materials like hemp is shifting and property owners, architects and developers are in an excellent position to make the most of the momentum and determine more constructive legislation and practices going forward. Now is the time for a ‘new normal’, in which environmentally-sustainable building materials and methods are the logical first choice.