Sustainability in Construction

Sustainability in construction is a vital issue that affects the future of our planet and society. The construction industry is responsible for a significant share of the global greenhouse gas emissions and environmental impacts, such as waste generation, resource depletion, land degradation and biodiversity loss. According to the United Nations Environment Program (UNEP), buildings account for 40% of the total energy-related CO2 emissions and 30% of the final energy use. Approximately 100 billion tones of waste is generated through construction and about 35% of this waste is sent to landfills. These figures are expected to increase as the demand for buildings and infrastructure grows, especially in developing countries. Therefore, it is imperative to adopt more sustainable practices and materials in the design, construction and operation of buildings and infrastructure, in order to reduce the environmental footprint and enhance the social and economic benefits of the construction industry.

The graph by UNEP below highlights the fact that the construction sector is not on track to decarbonize by 2050. Despite decarbonization boosts following the pandemic, thanks to low occupancy and consumption, the sector is far off the projected path to reach the target.

New Construction Methods

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One of the main strategies to achieve sustainability in construction is to use alternative methods that have lower carbon footprints and higher environmental benefits than conventional methods. For example, prefabrication and modular methods of construction can reduce waste and energy consumption by up to 30% and 50%, respectively, compared to traditional methods. Prefabrication and modular methods involve assembling standardized components that are manufactured off-site, which can improve the quality, efficiency and safety of the construction process. 3D printing can also enable more efficient and customized designs, reduce transportation costs, and reduce material waste to practically zero. 3D printing is a technology that uses computer-controlled machines to create three-dimensional objects layer by layer from various materials, such as concrete, metal, or plastic. 3D printing can be used for various applications in construction, such as creating complex shapes, repairing damaged structures or producing low-cost housing.

Alternative Materials

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Another strategy to promote sustainability in construction is to use natural materials that are renewable, biodegradable and carbon-sequestering. For instance, bamboo is a fast-growing plant that can be used for various structural and aesthetic purposes in construction, such as scaffolding, flooring, roofing or furniture. Bamboo has several advantages over conventional materials, such as high strength-to-weight ratio, low cost, easy availability and high carbon sequestration potential. Bamboo can grow up to one meter per day and sequester 5 to 24 tons of carbon per hectare per year, a rate that is 1.46x higher than fir forests and 1.33x higher than tropical rainforests.

Biomass, timber and wood are also widely available and versatile materials that can replace more energy-intensive and polluting materials, such as steel and concrete. Biomass is organic matter that can be used as a source of energy or material for construction, such as straw bales, hempcrete or biochar. Timber and wood are natural products that can be used for various structural and aesthetic purposes in construction, such as beams, columns, walls or floors. Timber and wood have several advantages over conventional materials, such as high strength-to-weight ratio, low embodied energy, high thermal insulation and high carbon storage potential. Timber and wood can store up to one ton of carbon per cubic meter of material, which can offset the emissions from the production and transportation of other materials.

The cement industry alone accounts for about 8% of global greenhouse gas emissions. One of the strategies to decarbonize non-renewable materials is to use clean and renewable energy sources for their production. This can lower the emissions from burning fossil fuels and make the processes more efficient. Another strategy is to reduce the demand for new raw materials by increasing the recycling and reuse of existing materials. This can also save energy and resources and reduce waste generation.

A third strategy is to improve the performance and emissions of the materials themselves. For example, concrete and cement can be made with less clinker and more alternative binders and aggregates, which can reduce the carbon intensity of production and improve the durability of the structures. Steel, aluminum, and glass can also adopt innovative technologies such as hydrogen-based reduction, carbon capture and storage, and improved furnace efficiency, which can lower emissions and increase the quality of the products. Plastics and polymer composites can also switch to bio-based and biodegradable materials, which can reduce the environmental impact and disposal of single-use plastics.

The graph by UNEP below highlights the relative share of materials per new building and their recycled components. It illustrates the fact that decarbonizing traditional materials such as cement and concrete and adopting bio-based materials consistently can significantly reduce carbon emissions.

Conclusion

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Sustainability in construction is not only a matter of environmental responsibility but also of economic opportunity and social equity. By adopting more sustainable methods and materials, the construction industry can reduce its costs, risks and liabilities, while enhancing its reputation, competitiveness and innovation. Sustainability in construction can also improve the quality of life, health and well-being of the people who live and work in the built environment, as well as of the communities and ecosystems that depend on it.

The construction industry has a key role to play in achieving the global goals of sustainable development. These goals require a transformation of the way we design, build, and operate buildings and infrastructure, to ensure that they are low-carbon, resource-efficient, resilient, and inclusive.

The construction industry has the potential and the responsibility to lead this transformation, by adopting more sustainable practices and materials, and by collaborating with other stakeholders, such as governments, academia, civil society, and consumers. Sustainability in construction is not only a challenge but also an opportunity, to create a better future for ourselves and for generations to come.