Affordable, sustainable, comfortable homes for all

How can we offer more and more people sustainable, comfortable homes in increasingly expensive and densely populated cities against the background of a climate change emergency that everyone now recognizes? That’s the question we face in providing the affordable homes of tomorrow. Here are some potential answers... 

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Build cheaper and more sustainably 

It’s essential that the homes we build are designed from the outset to be affordable and sustainable. The best option is to begin the process of upgrading the existing housing stock as soon as possible. 

Pascal Éveillard  - Director, Sustainable Business Development at Saint-Gobain  


Did you know?  

2 billion: that's the estimated number of buildings worldwide, and the vast majority of them are residential.  


Will Planet Earth soon be overpopulated? Without wishing to play Cassandra, it’s a question that deserves some thought. Flashback: in the 1960s, the global population totaled around 3 billion. Today, that figure is approaching 8 billion! And according to the latest UN forecasts, there will be 9.7 billion of us by 2050... with 70% of that total living in urban communities! So how are we going to house all these people?  

Galloping demographics, an aging population and accelerating urbanization mean that the housing shortage is raging on almost every continent. This surge can be explained partly by excessively high land prices, a shortage of real estate, and limited housing stocks at a time of ever-increasing demand... A quick look in the rear-view mirror reveals the eye of the storm: in 2021, real estate prices rose by an average 9.2% across 55 countries and regions; a figure that has obvious knock-on effects on housing supply. Estimates suggest that the UK would need to build 340,000 homes per year between now and 2031 simply to catch up... In Argentina, 4 million families are in urgent need of housing. 

So how do we respond to this crisis in housing? How can we design homes that are appropriate for today’s sustainability and comfort challenges, and yet at the same time be affordable? And most importantly, how could increasing the supply of ‘low-cost’ housing help to solve the global housing crisis?  

What do we actually mean by affordable housing? 

Let's begin with a clarification: ‘affordable housing' is a UK term that means “housing for sale or rent, for those whose needs are not met by the market”. On the basis of this definition, affordable housing is required by many different sectors of the population: the vulnerable, of course, but also students, seniors, young families, etc.  

Variable standards and stubborn clichés 

Beyond the disparate spectrum of profiles, the quality of affordable housing varies from one region of the world to another, since it has no direct correlation to household average incomes or local expectations in terms of comfort.  

Too often the collective unconscious perceives ‘affordable housing’ as hastily constructed buildings that soak up expensive energy and offer only a very basic level of comfort. It's high time we changed that perspective, because things are now changing irrevocably.  

Accessible everywhere and for everyone 

In its constant quest for ‘controlled costs’, the construction industry is experimenting with new solutions for building better and more cheaply in response to this major global crisis. The goal is to build affordable housing that is available everywhere and for everyone; homes that achieve “efficiency, comfort and sustainability goals” in the words of Felipe Faria, CEO of the Brazil Green Building Council in an interview with The Hidden Power of Materials Podcast. 

Of all the potential solutions available, prefabricated structures facilitate rapid construction at lower cost. The fact that thermally and acoustically insulated panels are assembled off site ensures high levels of energy performance. China - the current world champion in this field - is working flat out to mass-produce millimeter-perfect wall and floor panels. Like Lego®, the blocks are then assembled on site quickly and with great attention to detail, resulting in quality levels higher than those generally achieved by traditional construction methods. There are no longer any delays due to bad weather or issues around sub-standard construction skills, because everything is meticulously controlled and inspected before the buildings arrive on site!  

In the central Chinese city of Changsha (population 7 million), an 11-floor building constructed in just 28 hours highlights the potential offered by such affordable housing units, assembled from kits fabricated on an automated assembly line. On the other side of the globe in Africa, Saint-Gobain has developed ‘all-in-one’ solutions for the affordable housing market, including the Combi-pack combined ceiling and insulation kit for low-cost home construction. 




Local and traditional materials 

The lightweight and modular solution offered by timber framing is another high-potential construction option. “In Argentina, for example, timber plantations have the potential to support the sector in building affordable and environmentally responsible housing, since wood is a valuable material. However, the lack of investment and extremely high logistics costs are drawbacks that affect the competitiveness of products for domestic consumption,” explains Timo Marquez Arreaza, Saint-Gobain's Sustainable Marketing Manager. “On the other hand, in other countries, for example in Africa, the construction industry will favour other materials depending on local resources: straw, raw earth, hemp, etc.” In Soweto (South Africa), the affordable, high-quality social housing units in Devland have been built using clay bricks.  

This use of traditional materials is beneficial in three ways: the lower costs involved in using an abundant local resource, an optimized carbon footprint (less transportation) and support for the local economy. “In today’s world, affordable housing must address not only the financial equation, but also energy and environmental imperatives,” continues Timo Marquez Arreaza.  

Affordable and sustainable 

This is the whole point of affordable housing, which must be viewed through the prism of sustainability. Sustainability in its conception of a passive and bioclimatic architecture, which makes use of more natural and ecoresponsible materials. Sustainability in terms of durability, given the reality of climate change and increasingly frequent extreme weather events that will test building integrity and strength. Lastly, sustainability in terms of use, with high energy performance and low maintenance in order to reduce energy consumption and operating costs borne by populations for whom energy represents a major item in the budget - all the more so in a world where energy is becoming increasingly expensive. 

From this perspective, affordable housing must enable people to live economical daily lives. The stakes are high, especially in rental housing for low-income households.  
From building insulation and glazing performance to energy-efficient systems (condensing boilers, for example), there are so many ways in which households can live more cheaply as a result of more effective pre-construction design.  

This same logic applies to the upgrading of energy-intensive buildings. The most important priorities include the insulation of roof spaces, walls and windows, which greatly improves thermal and acoustic comfort, at the same time as cutting energy bills.  

If sustainability of use is one important aspect of affordable housing, sustainability of location is another. What is the point of building a low-cost home far from essential services, such as schools, health care, food supplies and employment? Can we still use the word ‘affordable’ if residents have to travel miles to go shopping or commute to and from work?  

“Thinking about affordable housing ultimately means thinking about all the issues we face today from a 360° perspective,” continues Timo Marquez Arreaza. “In order to envision the future of affordable housing, Saint-Gobain has set up a dedicated Task Force from 2021 onwards, whose objective is to support the development of affordable housing as a strategic and commercial ambition (as opposed to what could be merely a one-off philanthropic support). This Task Force consists of teams from Brazil, Argentina, India and South Africa who are exchanging with local governments and stakeholders on different themes: lightweight structures, passive housing, resource conservation, localization..." 

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Training construction professionals and educating the public 

The broader issue of training construction professionals is becoming increasingly important, because quality assurance is supported and driven by their expertise. As techniques evolve, so do materials, and it is important to maintain high standards of construction and installation to take advantage of all their thermal, acoustic and other properties. "Good training will ensure that solutions related to insulation, thermal bridges, moisture control and air tightness really work", analyzes Timo Marquez Arreaza. 

Green and social bonds 

One thing is certain, affordable housing seems to have a sustainable and responsible future. Increasingly strict building regulations are raising standards and imposing higher energy performance right around the world. And the emergence of green finance and the first social bonds appear likely to help promote and fund affordable, high-quality housing. In this context, affordable housing seems to have a sustainable and responsible future. 

Smart new buildings 

It is important that affordable housing should also benefit from new technologies like 3D printing, which is now becoming a more mature and realistic option. In Canada, for example, the first village of 3D printed buildings for low-income households will soon be under construction, and similar projects are under consideration in South America, Japan and the Middle East. This is because automated 3D printing shrinks construction lead times and reduces labor costs, at the same time as ensuring high-accuracy building design.  

The last word goes to Felipe Faria, CEO of the Brazil Green Building Council: “The future of affordable housing will rely on smart forward planning in the design phases, combined with pre-production and industrial construction methods. That combination is the key to success!”