The future of construction is now
Embracing new building products and strategies
Picture: rehack.com/science/transparent-wood
A greener future for housing in South Africa: Innovating for affordable and sustainable homes
To secure our children's future, developers are shifting to cleaner, more affordable, and efficient building methods and materials.
In a country like South Africa (SA), which faces a concerning shortage of affordable housing, developers are becoming passionate about finding cleaner, cheaper and more efficient ways of building. They’re embracing a cleaner future in SA, 30 years into our democracy. This includes researching alternative building methods and then piloting projects to see if they can excel at a mass scale.
Numerous government organisations are also helping to finance research institutes and universities that are testing varied building strategies. The goal is to ascertain which building methods can be used to alleviate housing problems at a manageable cost.
It’s a delicate process given that societal challenges need to be addressed when building any kind of structure in our country, especially homes. We face high levels of unemployment and poverty across our country. At the recent Residential Investment & Development (Reside) Conference, affordable housing group Calgro M3’s CEO Wikus Lategan said that developers in their market sector endeavour for their projects to create formal and informal jobs.
While the environmental effects of building must be managed, developers must pursue projects that create jobs.
Housing is also a personal aspect of our lives. Every person deserves a decent home to live in. If we look at people privileged enough to be able to afford to buy homes, the personal aspect shines through again. In fact, where to live and the amount of money spent on buying a house or renting it, are of the most stressful decisions anyone can make.
Builders have typically used brick and mortar to build structures in our country and have for centuries barely changed their techniques. Certain derivatives of brick-based materials are also used to roll out affordable housing schemes.
With these truths in place, some developers are still driven to innovate. They are studying and testing alternative materials that might be smarter and better suited to housing in SA’s climate, cleaner for the environment and even cheaper to use.
Research suggests that varied building methods and the use of certain building materials can help developers to save on different costs.
Driving green living and building cleaner
According to a recent Savills report that explores global trends in the real estate world, after several years of global disruption and macroeconomic volatility, there’s cause for optimism in real estate markets as healthier, greener living becomes increasingly important.
Savills is a global real estate services provider. The group showed that – as highlighted in a survey by estate agency Pam Golding Properties (PGP), which is Savills’ residential real estate partner in Africa – introducing green features to homes, such as solar and other forms of energy efficiency including grey water systems, rainwater collection tanks, boreholes and waterwise gardens, has become more commonplace in new builds and retrofits.
Also, many thousands of South African homeowners have embraced using renewable energy sources in their homes so that they can place less pressure on SA’s electricity grid.
PGP CEO Dr Andrew Golding says that sustainable building has become an important consideration rather than just a nice-to-have. “This is as South African consumers seek to achieve long-term financial savings as well as added value and saleability when the time comes to sell their homes,” he says. “There are also obvious benefits for the planet regarding the conservation of natural resources, and overall health benefits through reducing carbon emissions, energy efficiency and the like.
“The use of innovative building materials in the construction industry has increased dramatically in recent years, incorporating age-old as well as modern methods, each with its own characteristics and unique appeal, and demonstrating noteworthy creativity in the pursuit of renewable, eco-friendly solutions,” Dr Golding adds.
Sustainable natural resources – Not just typical bricks
SA has great examples of building methods that date back hundreds of years. For example, demonstrating the sustainability of centuries-old building materials and methods, corbelled houses such as those still seen in the Karoo and built from about the 1820s, are made using flat stones laid on top of one another and extending slightly further inwards until meeting at the apex.
Rammed earth is another ancient, environmentally friendly and aesthetically pleasing construction method that is being used today. It involves compacting earth, usually through combining gravel, sand and clay to form a building’s walls.
Some popular options among alternative building materials are:
- Natural materials: Wood, bamboo, straw bales, and clay
- Recycled materials: Recycled concrete, glass, and steel
- Bio-based materials: Hempcrete and cork
- Modern engineered materials: Insulated concrete forms (ICFs), cross-laminated timber (CLT), and structural insulated panels (SIPs)
Hempcrete
Houses, including treehouses and other structures like temples, all woven with bamboo, are popular in some climates, such as in Asian countries, where this cost-effective building material is readily available. A method using similar techniques is to build with the plant hemp that is made into hempcrete.
Hempcrete has become a commercially viable building material in several countries. In fact, in the past couple of years, an apartment building in Cape Town called 84 Harrington Street, achieved fame as it was built with carbon-negative hempcrete and hemp construction materials, which means it absorbs carbon dioxide, is energy-saving, durable and lightweight.
The 84 Harrington Street building was constructed mostly with hempcrete blocks and other building materials. Spanning 12 storeys, it’s been named the highest hempcrete-based building in the world. It was built in partnership between Hemporium and Afrimat Hemp, and aims to set the benchmark for how to build a safe, carbon-neutral, multi-floored structure, using hemp.
It was built in partnership between Hemporium and Afrimat Hemp and aims to set the benchmark for how to build a safe, carbon neutral, multi-floored structure, using hemp.
Afrimat Hemp, which is a Cape Town-based company, is a subsidiary of JSE-listed group, Afrimat. It specialises in hemp decortication and processing, natural building materials and bulk-processed hemp and natural fibres.
Managing Director of Afrimat Hemp, Boshoff Muller, explains that hemp has become a commercially viable material while numerous other alternative building materials to bricks, are still in their infancy and are being tested in numerous markets.
“We launched this business in 2021 and are now pioneering and beneficiating the industrial hemp value chain in Africa,” says Boshoff. “We have the expertise to bulk process the hemp plant and use it in natural, carbon-absorbing construction materials, breathable lime-based plasters and mortars. We believe that it is our duty to influence a worldwide movement to reduce global carbon emissions to net zero.”“We launched this business in 2021 and are now pioneering and beneficiating the industrial hemp value chain in Africa. We have the expertise to bulk process the hemp plant and use it in natural, carbon-absorbing construction materials, breathable lime-based plasters and mortars. We believe that it is our duty to influence a worldwide movement to reduce global carbon emissions to net zero,” says Muller.
Afrimat Hemp blocks
Founding partner and director of Hemporium, Tony Budden agrees that hemp is a building material which is in abundance in SA, and which hosts many positives for construction. He says hemp construction is considered as the gold standard for CO₂ reduction in buildings.
Hempcrete is an eco-friendly building material made from a mixture of hemp shiv (the woody core of the hemp plant), lime and water. It offers excellent insulation, fire resistance, mould resistance and acoustic or sound absorbing properties. Hempcrete also gained significant attention as a sustainable alternative to traditional building materials. It reduces energy consumption for heating and cooling, lowering carbon emissions.
Located in the East Precinct of Cape Town city centre, the 84 Harrington building project used Afrimat Hemp’s hempcrete block system. The walls were finished with Afrimat Hemp’s airPLAST and hempPLAST to promote breathability in the indoor climate and harmonise with the natural materials used, such as timber furniture. The substructure consisted of concrete columns, while airCOAT, a lime-based paint, was used for painting.
Tony says residential homes are built from hempcrete, while large office buildings require hemp blocks. Hemporium worked with proudly South African Wolf & Wolf Architects and R&N Master Builders to develop the hemp blocks for 84 Harrington Street.
“Now that hempcrete is being produced locally and for commercial use, we should see more construction companies showing an interest in hempcrete,” says Tony. “Consumers are also taking an interest in using it when building or renovating homes, which will also help to bring the price down.
“Hemp blocks are certified, which has given the construction industry confidence. We’ve built demo buildings that will instil confidence in the material for other projects going forward. My house, which was built 10 years ago, was done so with hemp. We also have the hemp soup kitchen in Khayelitsha and our hemp hotel in Harrington Street,” he adds.
Hempcrete is high in cellulose, which helps it to stay between 15 and 25 degrees Celsius, making it good for hot and cold climates. Hemp blocks are also being used in an attractive pipeline of buildings across SA, Malawi and Mozambique. The use of hemp is in construction courses and will be a part of university courses soon. Hemp blocks are also being used in an attractive pipeline of buildings across SA, Malawi, and Mozambique. The use of hemp is in construction courses and will be a part of university courses soon.
Other unusual materials
Transparent wood is a very recent eco-friendly material, said to be much stronger and more lightweight than glass. It is also flexible and contains efficient thermal properties. Used for windows, this wood from the quick-growing balsa tree is soaked in a special solution, with epoxy resin added.
Some South African developers are also testing waste materials for construction. Indeed, the recycling of materials has launched some successful business ventures while solving ongoing problems. Plastic bottles can be recycled to make bricks that provide good insulation for housing.
Other examples of alternative materials for bricks include straw bales, bricks made from construction waste and even bagasse, a by-product of sugarcane processing.
Tried and tested container living
Using shipping containers to build homes and other structures has in recent years caught on. Developers have built apartment blocks from them in the likes of Maboneng and other parts of Johannesburg as well as in Cape Town’s inner city. It is possible to have containers delivered to site in a couple of months, complete with selected finishes and ready to move in, which means there’s little construction debris or inconvenience.
3D printing as an aid
The 3D printing of parts of houses is being tested by numerous groups, even though a fully 3D-printed home is not deemed to be a commercial asset just yet. Apart from using cement and mortar, or clay and sand, 3D parts of homes can also be constructed using recycled materials such as plastic and other urban waste, eco-friendly materials like bioplastics for lower environmental impact, and even waste from rice production. A mixture of soil and seeds is also used to create “living” buildings that may sprout shoots and form green facades, with roots providing extra strength and stability to the structure.
Windows made with panels of glass filled with water can regulate temperatures by absorbing heat, thereby reducing the need for and cost of air conditioning, while cladding panels made from forestry and agricultural waste can store carbon.
Using what you already have
Self-healing concrete is made by getting concrete to react to certain additives. It enables the concrete to fill or heal cracks and cavities, and become even stronger. Dr Golding explains that there’s also a new additive consisting of polymer microfibres, which adds strength as well as flexibility to concrete. Waste from coal power plants is being added to concrete for extra strength and flexibility, which is ideal for areas that are prone to earthquakes.
It’s clear that alternative building materials offer a sustainable and innovative approach to traditional construction materials such as cement bricks, and prioritise reduced environmental impact, energy efficiency and durability. These materials present a diverse range of properties and applications, catering to different building needs and architectural styles.
SA possesses a rich and varied resource base, which provides a solid foundation for the development of alternative building materials. Our diverse climate change and landscapes also support the production of a range of sustainable options. Traditional materials such as cement bricks dominate the market, but there’s a growing recognition of not only the potential offered by local alternatives, but also the need to invest in sustainable materials.
SA's diverse climate necessitates the use of building materials and methods that are well suited to different regions. For example:
Hot and arid regions
Materials with high thermal mass and insulation properties, such as clay and hempcrete, can help regulate indoor temperatures.
Coastal areas
Materials resistant to moisture and salt, such as treated wood and certain types of concrete, are suitable.
Cold regions
Insulation and airtightness are crucial. Materials like hempcrete and straw bales can provide excellent thermal performance.
The future is now if industry players come together and embrace new building strategies. Absa Home Loans is optimistic that alternative building strategies and materials will gain popularity and be used for commercial purposes, so that green buildings become desired in society and hold substantial value of their own.