BUILDING SUSTAINABLY MEANS CONSUMING LESS WATER

There is a good reason we call the Earth the "blue planet." Composed of 70% water, our beautiful world reminds us what a precious and essential resource it is – and one we must preserve. And yet our Earth is thirsty. According to the WHO (World Health Organization), one in three people today does not have access to drinking water. And two-thirds of the world's population will face water shortages by 2025, according to the United Nations. 

The regions most affected by this water stress are the Near East, the Middle East, Africa, and Asia, as they suffer intense periods of drought. The paradox is that while three billion people experience a severe lack of water, others act as if this resource were inexhaustible. It is not… Water stress needs to be taken very seriously. In 2019, the World Economic Forum even identified the phenomenon as one of the world's most significant risks in the coming years. This results from increasingly violent climatic episodes, which permanently degrade our water reserves and exacerbate global social inequalities. And the situation is likely to worsen, as some experts expect the planet to become more than two degrees warmer by 2040. So, are we heading for a water shortage? Many experts sound the alarm, especially in the industrial and construction sectors, which consume large quantities of water.

Dry or wet construction? 

Construction consumes a lot of water from materials design to concrete production and uses on worksites. Too much. Yet to be truly sustainable, our construction sectors need to promote water resilience in their design and use. So how do we achieve this? 

At the forefront of this growing awareness, dry construction is becoming increasingly popular. As its name suggests, this approach uses no water on worksites and, therefore, no poured cement or concrete. Instead, dry structure favors wood or steel walls and frameworks, ready to be assembled on-site without needing a single drop of water. Other "dry" approaches include the prefabrication of components in the factory, dry screeds, and lightweight partitions, which significantly reduce water consumption during manufacture. The positive results have better resource control, optimal cost management, and simple and rapid implementation.  

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Hard times for concrete 

Could this be the end of wet construction? Let's not jump to conclusions, as this is far from the end of the road for concrete. Long singled out for its environmentally suspect production methods; concrete is having a makeover as cement manufacturers innovate with new formulations designed to minimize their environmental footprint and, more significantly, their water consumption. For instance, Chryso – a Saint-Gobain subsidiary – has developed Chryso® AMT 2, a grinding agent that substantially reduces the amount of mixing water required to produce concrete. This is the water incorporated into the binder and aggregate mixture, activating the setting of the concrete and giving it its plasticity. 

Although concrete is becoming more virtuous, other solutions stand out for its low water consumption. This is particularly true of many environmentally-friendly materials, which are part of a comprehensive approach to sustainable construction. Take adobe, which is widely used in Africa and desert areas. This age-old construction method uses unprocessed local Earth to build the walls of a house. It is simple, healthy, and above all, very economical in terms of energy and water. Another alternative is hemp. Grown without pesticides or irrigation, it is used in construction as natural insulation or hemp concrete to replace concrete blocks. These are laid dry simply by interlocking the blocks like a Lego© set. 

Best practice on worksites  

Saving water, therefore, means taking an overall life-cycle approach (production/manufacturing of products, use, then recycling) while trying to consume as little water as possible throughout the process. But that is not enough. Because to win the battle for water, everyone must take action, including on worksites. There can be no question of pouring concrete in hot weather, for example, which would involve frequent watering of the screed. We are in an era of greater responsibility, and it is essential for worksites to minimize all their impacts by taking a more ecological approach, whether in terms of discharges into or adduction from the natural environment.