Architecture encompasses multiple processes, starting with identifying needs and transforming them into habitable structures through thoughtful design. Historically, construction-related processes like resource extraction and end-of-life disposal were often overlooked. However, it is essential to recognize that buildings have a lifecycle with significant impacts on carbon emissions. Emphasizing sustainable practices is vital to minimize our ecological footprint and positively impact the planet.
The urgency to reduce CO₂ emissions is present in various fields, including architecture. To do so, it is essential to adopt a cyclical perspective rather than a linear one when approaching construction processes. To effectively achieve the decarbonization of architecture, it is crucial to promote innovative and sustainable solutions, such as those pioneered by Holcim, that enable the reduction of carbon emissions throughout the entire life cycle of buildings. Globally scalable building solutions can be achieved by optimizing resources, using 3D printing technologies, employing recycled materials, and integrating nature into urban environments. In exploring the various possibilities for achieving CO₂-free architecture, we have selected approaches that promote energy efficiency, retrofitting, the use of new technologies, and contribute to a positive impact on nature and the surrounding environment.
Building better with less
According to World GBC, buildings are currently responsible for 39% of global CO₂ emissions. One-third of this footprint comes from the construction phase, while the remainder is generated in buildings in use. To enhance economic efficiency, minimize waste, and improve environmental sustainability, optimizing resources during construction is crucial. This approach leads to better-quality structures while reducing the consumption of natural resources and polluting emissions. In this way, we can build better with less environmental impact.
To reduce the carbon emissions associated with concrete, it is necessary to go back to the manufacturing processes. Some existing strategies have involved reducing specific fuel consumption during cement production —a key element in concrete manufacturing— or coming up with new proposals with the materials that make up concrete, modifying their composition to develop different ranges of lower-carbon cement and thus reducing CO₂ emissions. These low-carbon material solutions are obtained through green formulations with alternative materials, such as calcined clay, and using alternative fuels derived from materials at the end of their life cycle during the manufacturing process. These offer a CO₂ reduction of at least 30% compared to standard types of cement. They are currently used in multiple high-performance applications and projects, including stadiums, bridges, dams, high-rise buildings, and other large structures with specific technical requirements.
Similarly, low-carbon concrete solutions represent a great opportunity to decarbonize buildings. Concretes of this type are produced locally and are fully recyclable, enabling circular construction. They include recycled construction and demolition waste, combining a low carbon footprint with circular benefits. Their use can reduce CO₂ emissions by at least 30% compared to their market reference, without compromising performance across a wide range of structural components, extending beyond just homes. It can also be easily handled, pumped, and finished like conventional concrete, and is suitable for foundations, pillars, beams, walls, driveways, and sidewalks, among other applications.
In addition, today's evolving 3D concrete printing technology has become a tool that not only provides new ways to materialize building solutions but also improves their performance and enables more efficient construction, closing infrastructure gaps around the world. These advances also mean that the materials used must evolve at the pace of technology and its specific requirements. By optimizing the use of materials, 3D printing translates into more efficient buildings that make better use of resources and reduce the need for complex structures.
In the cement industry, advanced mortars have been developed for 3D printing to streamline the construction of large-scale projects and improve logistics. These highly adaptable solutions meet specific requirements and enable smarter designs, reducing material usage on a project by up to 50% without compromising performance. 3D printing uses only the materials needed for buildings, and advanced mortars optimize the amount of material used and minimize errors in construction sites, allowing large-scale projects to be built faster.
Making buildings sustainable in use
Sustainable buildings are designed and built with a focus on energy efficiency, responsible water use, thermal insulation systems, and practices that reduce their environmental impact during operation. It is estimated that up to 80% of today's buildings will still be in use by 2050, highlighting the importance of adopting practices that minimize their impact and contribute to the energy efficiency, repair, renovation, and rehabilitation of spaces.
To enhance energy efficiency, smart insulation systems are a useful strategy to improve the performance and efficiency of buildings. One such system is made up of a fully recyclable mineral foam, composed of a cement-based slurry, aqueous foam, and enclosed and distributed air bubbles. This makes them adaptable to different structures and climatic conditions and also a viable option for improving the efficiency of the building envelope. By using Airium, it is possible to limit the environmental footprint and reduce heating and cooling costs. Moreover, being mineral-based, it does not emit volatile organic compounds, thus improving indoor air quality.
Applied as a semi-liquid foam, Airium makes it possible to reach every corner and, as it hardens, creates a durable and fire-resistant insulation solution, which also makes it unfavorable to insects and rodents. Additionally, it features a low CO₂ footprint and is suitable for both new construction and renovations, covering elements such as ceilings, walls, floors, and block infill.
Roofing solutions also play a key role in the quest for more sustainable and energy-efficient buildings. Holcim offers sustainable, high-performance shingles for residential roofing solutions, designed to last and with a smaller environmental footprint, including ice and water barriers. These shingles result in high performance, cost-effectiveness, and circularity, as plastic bags and tires are upcycled in each average-sized roof. For commercial roofing solutions, a wide range of green and cool roof systems are available to improve energy efficiency in urban areas. They play a key role in reducing the heat island effect, common in large urban centers where the landscape has gone from green to gray.
Green roofs, featuring vegetation, excel at insulation, effectively reducing both heating and cooling demands, while also serving as natural filters for air pollutants. In contrast, cool roof systems are designed to reflect a significant portion of solar radiation, minimizing heat absorption by buildings. In urban settings, where temperatures can soar due to the concentration of buildings and limited greenery, adopting these roofing solutions can yield widespread and beneficial effects.
In addition to roofing solutions, when considering sustainability in building use and the integration of nature into urban environments, there is a wide range of lining solutions available to address various challenges while maintaining aesthetics and performance. These options range from garden ponds to irrigation reservoirs and silage covers. Additionally, geomembranes offer a durable waterproofing solution suitable for various agricultural, industrial, and commercial applications, providing fast, easy, and safe installation. Lining solutions play a crucial role in enhancing energy efficiency in architecture by providing thermal insulation, air sealing, moisture control, and durability, ultimately contributing to reduced energy consumption, lower utility bills, and a more sustainable and comfortable built environment.
Protecting buildings over the long term is an integral part of making them sustainable in use, aligning with the principles of resource and energy efficiency, and durability. In this context, waterproofing solutions include protective products that serve functional and highly decorative purposes in public buildings and parks. Among their benefits are cost-effectiveness and ease of installation, achieved through multiple coating chemistries in single or multi-component systems with various installation and performance efficiencies, which ultimately reduces labor requirements and costs.
The use of recycled and demolition waste materials in construction is vitally important to foster environmental sustainability and drive circular construction in the industry. Construction and demolition activities generate millions of tons of waste worldwide each year. Holcim aims to recycle at least 10 million tons of demolition materials per year from construction by 2025. To achieve this vision, ECOCycle, a circular technology platform has been developed to recycle construction demolition materials into new building solutions without compromising performance. This range includes products such as cement, concrete, and aggregates for a broad spectrum of applications. All of these products contain between 10% and 100% recycled demolition materials.
Cement with ECOCycle in it, for example, contains at least 10% recycled demolition materials, thus closing the loop in construction. Concrete with ECOCycle is suitable for a wide range of applications, from buildings to infrastructure, and is completely recyclable at the end of its life cycle. Holcim's global range of circular aggregates contains up to 100% construction demolition materials and can be used in construction applications from roads to foundations.
Holcim's circular technology platform enables circular construction at scale, reducing the use of natural resources and promoting a global circular economy. Their positive impact on biodiversity, ecosystem regeneration, and contribution to a nature-positive future is achieved by recycling construction demolition materials into building materials, resulting in fewer natural resource extractions, reduced waste sent to landfills, and the implementation of a closed-loop system in construction, where new structures are built using reclaimed materials from old ones.
Overall, the fundamental strategy is to unite efforts from diverse perspectives to achieve a global impact on the decarbonization of buildings. Numerous building solutions already exist in contemporary industry, and it is undeniable that improvements in their processing and use can have a significant impact on our planet and people's quality of life. The journey toward global decarbonization of architecture is a multifaceted endeavor that requires collaboration between architects and designers, innovation by companies like Holcim, education, and advocacy. By uniting efforts from various perspectives and embracing sustainable building solutions, we can make a significant and positive impact on our planet and the built environment, enhancing the quality of life for current and future generations.
For more information about Holcim and solutions for decarbonizing buildings, visit the Holcim website or refer to the product catalog.
This article is part of the ArchDaily Topics: Decarbonize Architecture presented by Holcim.
Driven by its purpose to build progress for people and the planet, Holcim is decarbonizing building, while improving living standards for all. Holcim empowers architects and developers across all regions to build sustainably. This series explores how cities of the future can be low-carbon, circular, and resilient.
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