Sustainable buildings and the circular economy: Tackling challenges in the next two decades

The field of architecture, engineering and construction (AEC) has been rapidly growing in the past decades. Technological innovations and increased demand have developed the industry to a scale never thought possible.

However, the increased number of big construction projects and the associated material manufacturing is having a negative effect on the environment. Greenhouse gas (GHG) emissions are at an all-time high, resulting in a number of environmental, economic, social and health implications.

The concept of the circular economy (or simply, circularity) was developed to address those important issues. It promotes a closed-loop production and consumption model that minimizes resource waste while encouraging reusing, recycling and sharing existing materials.

Buildings and the circular economy

As far as the building and construction industry are concerned, circular economy principles mostly relate to the use of cement and steel. Those materials have the highest GHG emissions of all building materials. In fact, the global cement production industry is responsible for around 8% of the carbon dioxide (CO2) emissions worldwide, while steel production generates around 7%. However, those numbers are expected to rise in the near future, as production of both materials ramps up.

Steel and cement manufacturing uses a lot of energy, which increases the overall carbon footprint of those industries. On top of that, the process of limestone calcination, which is required in the production of cement, also results in high levels of CO2. Steel manufacturing, on the other hand, also includes chemical processes that generate high levels of CO2 emissions.

The circular economy aims to reduce the GHG emissions from steel and cement by finding suitable alternatives and implementing effective recycling and reusing processes. However, there are many more aspects in which the circular economy can affect the construction industry and ensure sustainable buildings in the near future.

The challenges facing sustainable buildings

Even though the concept of circularity has been around for quite some time, its principles have yet to be fully implemented in the AEC industry. Steps are being taken, but there are many challenges that must be addressed first.

Let’s take a look at five issues that need to be taken care of in the next couple of decades to ensure sustainable buildings and circularity in construction as a whole.

1. Material reduction

As of right now, buildings are usually constructed with much more materials than actually needed. This is in part because architects and engineers want to ensure the stability, safety and resilience of the building.

Modern designs need to reduce the usage of steel and cement without compromising the structural integrity of the project. New technologies, such as building information modeling software, can help with that matter immensely. By creating efficient designs with just the right amount of materials needed, the AEC industry can significantly reduce its carbon footprint.

An additional factor that plays a part in this is the fact that creating more material-efficient buildings will result in higher labor costs. But, the AEC industry needs to change its approach and focus on creating leaner designs for the buildings of the future.

2. Substitutes and alternatives to cement and steel

One of the main concepts of the circular economy is finding suitable alternatives to materials that generate harmful emissions. When it comes to construction, there are several viable substitutes for steel and cement. The industry is already taking steps to properly integrate them, but more work needs to be done.

Timber, for example, is an excellent alternative. Trees absorb CO2 and can effectively contain it as long as they are intact. Timber can also be easily reused and recycled. However, proper sourcing of timber needs to be considered because deforestation also has a major effect on global CO2 pollution.

As far as cement is concerned, there are new types that generate significantly less CO2 during the manufacturing process. Modern cement has a different chemical composition that makes it much more eco-friendly and sustainable. However, demand for it is quite low. This is mostly due to the price and lack of incentives for construction companies in developed countries.

3. Sustainable design

A key factor that determines the circularity of a building is whether its components can be easily disassembled and then reused. If materials do not go to waste, the impact on CO2 emissions is considerable.

New designs need to be created with disassembly in mind, essentially ensuring that they can be used as a source of materials for future projects. However, creating sustainable designs is just one aspect of the matter, as logistics and organization should also be considered.

4. Reusing materials

Even though reusing construction materials has been a topic for quite some time, no significant progress has been made. The amount of steel, cement and concrete that are being reused is quite small. Even though recycling is becoming more and more popular, reusing is much better when it comes to circularity principles. After all, recycling consumes a lot of energy, generating CO2 emissions in the process. Reusing materials, on the other hand, does not involve such actions.

However, the AEC industry needs to come up with standards for steel, cement and concrete that ensure their reusability. The sustainable building design we discussed in the previous point will also be a huge step toward achieving that goal.

5. Renovation of existing buildings

Another component of circularity is minimizing the demand for new buildings, thus reducing CO2 emissions. Instead of demolishing and rebuilding existing structures, people need to start renovating old buildings in an energy-efficient way. This will not only prolong the building’s longevity but also ensure that it is sustainable in the long run.

Of course, renovations also require the use of materials and GHG-generating processes. For this reason, the AEC industry has to adapt the principles of the circular economy and use energy-efficient materials when refurbishing old buildings.

– DEP is a CFE Media and Technology content partner.

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