While understanding of sustainable development has increased in recent years, we had to go through an unprecedented environmental and health crisis, Covid-19, to boost our collective awareness and see it as an essential condition for the survival of both the planet and ourselves.

The crisis has triggered transitions in many walks of life, from race relations and sustainable food to greener transportation and the reduction of our plastics consumption.

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But sustainable development also implies massive changes should be made in the construction industry. Though not yet well known by the general public, it is clearly identified by all experts and governments in their approach to sustainable development. When adding emissions from the building construction industry on top of operational emissions, the sector accounted for 38% of total global energy-related carbon dioxide emissions, the UN estimates.

At the same time, having a place to live is a basic and non-negotiable requirement for everyone. Construction is therefore a sector in which innovation, behavioural change and adapted regulations will play a key role to achieve our common need for sustainable development.

It is in China, where the pandemic started, that this huge challenge for the construction industry is most striking. Any observer of the country can see the massive development of its megalopolises, the new infrastructures and high-rise buildings built to provide homes to growing city populations. Considering the huge quantity of materials required and the energy consumed, there is clearly an urgent need to find ways to make new construction activity sustainable.

In 2018, total emissions from the whole value chain of the building sector made up more than 51.% of China’s carbon dioxide emissions, according to the China Association of Building Energy Efficiency. That includes emissions from the production of materials (28.3%); the actual construction of buildings (1%); and their operation and maintenance (21.9%). 

With China’s urbanisation rate set to swell to 70% by 2030, the task of decarbonising construction is all the more pressing. The Chinese authorities are aware of this challenge, and have put sustainable construction at the centre of the country’s priorities.

Green building  

‘Green building’ is an expression that gets bandied around when we talk about sustainable construction. But what exactly does it mean? The World Green Building Council defines a ‘green’ building as “a building that, in its design, construction or operation, reduces or eliminates negative impacts, and can create positive impacts, on our climate and natural environment”.

The definition clearly states the necessity to address all aspects of a building’s lifecycle to reduce or eliminate their impact on the environment, and the requirement to consider three different aspects: the design and construction of the building, its operation, and the materials used to build it.

In the construction industry, productivity and innovation have been rather poor over the past few decades compared to other sectors. Labour productivity growth in construction has averaged only 1% a year over the past two decades, compared with an average growth of 2.8% in the total world economy, and 3.6% in manufacturing. Since we don’t build that differently today than we used to a century ago, there have been fewer improvements in terms of productivity, quantity of materials, or energy used.

Going prefab

In recent years, however, innovative construction methods such as prefabricated construction have seen quick adoption in China. Unlike traditional construction methods, building components are partly or fully prefabricated or pre-assembled in a factory, then transported to a site.

In so doing, industrial methods are partially brought to the construction sector, along with better monitoring of the materials’ performance, better productivity, less waste and the optimised use of all resources. 

Thanks to a large number of digital technologies, prefabricated modules in factories substantially reduce waste, water and other resources and greatly improve construction efficiency. There are several maturation levels of prefabrication within the building sector: from precast concrete building elements to full pre-assembled modules installed on site. Whether it is single-family construction, large apartment buildings, hotels, or hospitals, prefab construction is on average anywhere between 25% and 50% faster than ground-up construction.

Prefabrication goes hand-in-hand with the digitisation of the construction lifecycle. Smart building design offers a fantastic opportunity to boost manufacturing efficiency and sustainability by anticipating all kinds of jobsite constraints at the design stage — thus optimising productivity and better assessing building performance, but also better synchronising transportation and deliveries. All of this gives construction ‘green’ credentials. 

The China State Council set a target of prefabricated buildings accounting for 30% of new buildings by 2026. In 2020, the share of prefabricated buildings reached 20.5% of new buildings, with an increase of 50.7% of new prefabricated buildings from 2019 to 2020. And the upcoming targets are even greater, with an ambition to reach 60% of assembled buildings in the new construction area by 2060. If achieved, the prefabricated market may exceed Rmb10tn ($1.5tn). 

The Yangtze Delta is taking the lead in the prefabricated industry. Shanghai, Jiangsu and Zhejiang provinces have set a goal of having between 30% and 55% of prefabricated buildings in new building construction by 2025. 

Today, prefabrication mainly applies to structural parts of the building in China but change towards prefabricated decoration elements is also on the horizon.

Environmental impact  

With 21.9% of China’s energy consumption used to operate buildings as of 2018, according to the China Association of Building Energy Efficiency, understandably there is still a fair amount to do.

On the one hand, the use of green energy to replace carbon-based energy is critical. The Ministry of Housing and Urban-Rural Development of China recently pushed for Building Integrated Photovoltaic (BIPV), which directly uses photovoltaic modules as building material to generate electricity. In June 2020, the National Energy Administration set the target to use at least 50% of the Chinese Communist Party (CCP) and government building roofs and 20% of the rural resident building roofs to install photovoltaic panels. 

On the other hand, thermal insulation of buildings is of major importance to reduce their energy consumption and carbon emissions. Recent studies in China showed current energy losses through external walls reaching between 23% and 43%.

While China has experienced unprecedented economic growth in the last 30 years, in order to absorb the massive flow of its populace moving from rural areas to cities every year, most buildings were poorly insulated. Trends are today moving forward with vast plans for renovation and new regulations in the insulation of new buildings.

The National Compulsory Engineering Construction Code ‘General specification for building energy conservation and renewable energy utilisation’ is expected to be officially introduced in the next few months and emphasises the systematic supply of thermal insulation in new buildings. By using different materials to line walls, and better glass insulation, China will significantly decrease the consumption of energy by its building operations. 

Sustainable materials

Making buildings ‘green’ first requires using the least amount of materials, thus moving towards lighter construction. As this cannot be done at the expense of lesser performance, it is essential to improve expertise about construction materials and be able to innovate towards more performant and sustainable ones. Having the best mechanical properties using as little material as possible, and having good acoustic, thermal, but also aesthetic properties, are key aspects of making our buildings greener.

As part of this research for greener materials, recyclability is a key factor to minimise use of natural resources. Being able to recycle building materials, or designing building solutions that are easily recycled, is crucial to achieving the goal of sustainable construction.

Achieving green building construction is a long journey. From raw material extraction to manufacturing, transportation, building construction and operations, every stage of a building’s lifecycle must be taken into consideration and improved, integrating digital tools to optimise the whole value chain. Developing our collective expertise to assess, in an exhaustive way, the environmental impacts of buildings is also an exciting challenge.

Today, China is the number one market in the construction sector. It accounts for 23% of the worldwide market, according to Fitch Solutions, and represents 17.2% of the world green building market. The government has a target of 70% green buildings in its new urban building market by 2022.

If we take as reference the LEED certification (Leadership in Energy and Environmental Design), China has made substantial strides. In 2020, the country came top of the annual list of LEED certification buildings for the fifth consecutive year, with more than 1190 newly added LEED registration projects, up by 50% compared to 2019.

In Shanghai, 48% of the Grade-A office buildings (modern buildings with high quality finishes) acquired LEED certification in 2020. Even if LEED-certified buildings remain marginal in the total new building constructions, it shows the Chinese government’s commitment to the promotion of green building.

China has clearly drawn up a road map toward sustainable construction. No doubt it will gather its strength to become carbon neutral by 2060 — and thus will keep innovating in the sustainable construction field. 

Ludovic Weber is CEO of Saint-Gobain Asia-Pacific. 

This article first appeared in the October/November print edition of fDi Intelligence. View a digital edition of the magazine here.