More than bricks and mortar

Since mankind has become sedentary, it has begun to build shelters for itself. Their design has always been determined by the climate, whether they were to provide protection from the cold or heat, wind or storm. The US architect Philip Johnson once said: “All architecture is shelter.” 

Today, humanity has reached a point where the opposite threatens to become the case: The task of how houses can protect people from the environment must now be supplemented by the task of how people can protect the environment from their houses as studies such as the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (2022) show. 

According to this authoritative examination, total greenhouse gas (GHG) emissions in the building sector reached 21 percent of global GHG emissions in 2019. Of this, 57 percent were indirect CO2 emissions from offsite generation of electricity and heat, followed by 24 percent of direct CO2 emissions produced on-site and 18 percent from the production of cement and steel used for the construction and/ or refurbishment of buildings. Globally, buildings account for almost a third of CO2 emissions and just over a fifth of GHG emissions. 

Houses are recognized as major causes of emissions and cities are responding. Meanwhile, demand for new accommodation is rapidly, and massively, rising. According to UN-Habitat, the United Nations program for human settlements and sustainable urban development, around 1.6 billion people worldwide lack adequate housing today. By 2030 this could rise to 3 billion. To meet this demand, the world needs to build 96,000 affordable homes every day. However, in many countries the population grows faster than homes are being built. Take, for example, the USA: While the US population grew by more than 3 million people in the last 20 years, home construction decreased by 55 percent nationwide. 

If the largest economy in the world cannot cope, the prospects for developing countries are even more daunting. The world is witnessing a massive shift towards urbanization (see interview Oliver Harman, page 18), with 6 out of 10 people expected to live in urban areas by 2030. Over 90 percent of this growth will take place in Africa, Asia, Latin America and the Caribbean. A survey by the Thomson Reuters Foundation, a charity promoting media freedom, inclusive economies and human rights, illustrates what this means for Africa: At current rates of population growth 70 percent of the buildings that will be needed in Africa in 2040 are yet to be constructed. 

Some see this as an opportunity: “Just like with the mobile phone, we don’t have to go through the landline just because the Global North did it,” says Caitlin Wale, founder of the African climate tech accelerator Kinjani. “We have the potential to grow green from the start.” Her enterprise is raising capital to “capture the massive climate opportunity” and help companies with access to much-needed funds. 

One starting point are construction materials: Cutting-edge technologies and processes needed to green the building sector, such as the production of lower-carbon cement, have often been developed in advanced economies. As imports are expensive and not necessarily the best option for local markets, architects in Nigeria “rediscovered” local materials like red clay bricks which are more suited to the country’s climate as well as being more weather resilient. In other cases, as a substitute for cement in concrete, scientists developed ways to use mining waste and biochar, which is produced from heating biomass. 

The OPEC Fund is supporting a project to provide affordable and sustainable housing in the Sahel region in Africa which is based on ancient techniques and traditional expertise. The so-called Nubian vault, named after the region’s ethnic group from the Nile Valley, is an environmentally friendly and sustainable way of using pure earth to build roofs and ceilings without the need for timber. 

Another example comes from India where low-cost materials are used instead of bricks and mortar to bring down the price of housing and speed up the building process. The Indian government is constructing thousands of homes using glass fiber reinforced gypsum to create a strong yet lightweight panel which can be used for walls, floors and roofs. The reduced need for cement and steel not only makes such homes up to 30 percent cheaper, it also significantly lowers their carbon footprint. 

India, according to the World Economic Forum, has a shortage of 34 million housing units. The situation is even more pressing in Africa: “The housing deficit in Africa is estimated at over 97 million units and this is expected to increase as the continent’s population grows, and urbanization continues,” reports the International Finance Corporation (IFC), the World Bank’s private sector arm. 

New technology is playing an increased role in addressing this gap: In 3D-printed homes, the primary structural components like walls and foundations are constructed using industrial-sized 3D printers which follow a digital template to “print” the property layer-by-layer using cement, concrete and other building materials. After the 3D printing of the core structure, builders add other parts like the windows, plumbing and electrical wiring through traditional construction methods. 

The main benefits of 3D-printed homes are reduced construction time – “printing” the foundations and walls can take a day or two instead of several weeks – and lower costs as the properties are estimated to be at least 20 percent cheaper than traditionally built homes. 

In Africa, a joint venture involving the UK development finance institution CDC Group and the multinational building materials manufacturer Holcim is 3D-printing houses and schools in a fraction of the time it would normally take to construct them. Called 14Trees, it has operations in Malawi and Kenya and is able to build a 3D-printed house in just 12 hours at a cost of under US$10,000. Its building process reduces CO2 emissions by as much as 70 percent when compared with a typical house-building project. 

The company’s first-ever affordable, 3D-printed home was built in Lilongwe, the capital city of Malawi. 14Trees has also recently completed its first 3D-printed school, also in Malawi, built in a fraction of the time a traditionally-built school would take. Co-financed by IFC “the project will demonstrate the viability of the sector to local developers,” the World Bank subsidiary said. 

But building new homes alone will not be enough. Estimates show that two-thirds of the buildings that exist today will still be around in 2050 – “presenting both structural and environmental problems,” as the World Bank says in a recent paper. The good news is that technology is already available to address these issues: 3D scans are mapping informal settlements, while machine learning software is being used to efficiently and cheaply identify buildings at risk of collapse. 

Newer technologies such as light-reflecting paint and low-cost structural retrofit techniques can go a long way toward making homes safer and greener. Augmenting these technologies, many experts believe digitalization will be the big gamechanger. Across all project stages, digitalization could increase materials’ efficiency by integrating life-cycle emissions, using 3D building information modeling, enhancing collaboration in the construction process through management apps on mobile devices and monitoring sites with drones for scanning. 

Paper-based work practices, cost increases and technological illiteracy are, however, likely to represent key barriers in developing countries, especially in low-income and fragile countries as well as middle-income economies with construction sectors featuring a large presence of informal and small construction companies. 

Internet-connected appliances can help reduce energy consumption by enabling the use of dynamic electric pricing and time-of-use tariffs. These smart appliances, along with energy efficient management retrofit systems, can reduce energy consumption by 20 to 30 percent. The Super-Efficient Equipment and Appliance Deployment Initiative, led by the International Energy Agency, for instance, provides support to more than 20 governments to implement energy efficient policies for appliances and equipment and identify and promote the adoption of innovative smart devices and systems. 

Could digitalization provide solutions to the housing crisis? 

Digitalization has the potential to significantly alleviate the housing crisis in the developing world through several key mechanisms: 

• Cost Reduction: Technologies like 3D printing and prefabrication can drastically reduce construction costs and time. For example, 3D-printed homes can be built quickly and affordably, making housing more accessible. 
• Improved Planning and Management: Digital tools such as Building Information Modeling and Geographic Information Systems can enhance urban planning and infrastructure management. These tools help in efficiently designing and managing housing projects, ensuring better use of resources and space. 
• Enhanced Financing Options: Digital platforms can streamline the process of obtaining housing finance. Automated underwriting and digital mortgage platforms can make it easier for people in developing countries to access loans, reducing barriers to homeownership. 
• Data-Driven Decision Making: The use of big data and artificial intelligence can help governments and organizations identify housing needs more accurately and allocate resources more effectively. This can lead to more targeted and efficient housing policies. 
• Smart Homes and Energy Efficiency: Digital technologies can also improve the quality of housing by integrating smart home systems that enhance energy efficiency and reduce utility costs. This not only makes housing more affordable but also more sustainable. 

A green revolution? 

New technologies hold so much promise that everybody from Eurocrats to estate agents are speaking of a “green revolution in building.” But technology alone is not a silver bullet: A recent World Bank paper asks for innovative financing, long-term policy changes and new approaches from planning to implementation, arguing: “The greenest home built in suburbia is still more polluting than a classic urban house. As we embrace innovative construction technologies, let us not forget that housing is more than bricks and mortar.” 

The Internet of Things (IoT) can play a transformative role by enhancing the functionality and efficiency of homes. 

Here are some examples how IoT can contribute: 

• Personalized Living Spaces - IoT systems can learn from user behavior and preferences to create personalized living environments. This can enhance the quality of life for residents by providing comfort and convenience tailored to their needs. 
• Remote Monitoring and Maintenance - IoT sensors can monitor the condition of home systems such as heating, ventilation, air conditioning, plumbing and electrical. They can alert homeowners to potential issues before they become major problems, reducing repair costs and improving the longevity of housing infrastructure. 
• Enhanced Security - IoT devices like smart cameras, door locks and motion sensors provide real-time monitoring and alerts, improving the safety and security of homes. 
• Energy Efficiency - Smart thermostats, lighting systems and appliances can optimize energy usage based on real-time data and user preferences. This not only reduces costs but also promotes sustainability. 
• Improved Communication - IoT can facilitate better communication between residents and housing providers. For example, residents can report issues or request services through smart home systems, leading to quicker responses and more efficient management. 
• Automation and Control - IoT enables the automation of various home functions such as lighting, heating and security systems. This can lead to more efficient use of resources and lower utility costs, making housing more affordable.