The five case studies presented offer ways of implementation of circular economy to the construction industry from their own aspects. The three main pillars regarding the implementation are designing for disassembly, building with recycled materials and building repurposing. Each of these pillars presents their own advantages and disadvantages; however, one thing is shared between all of them: the concepts still require further development in order to become widely used standards in the industry.
The fifth case study offered insights and examples of material passports and how they can contribute to the modernisation of the construction sphere.
Building for disassembly
Building for disassembly is a great design solution that allows the life span of main elements and materials of a building to be extended, leading to direct cuts in both construction emissions as well as resource exploitation. The case study The Four Administrations presents a comprehensive and well-detailed solution on how this particular construction method can also offer cost benefits in addition to its more obvious environmental benefits.
A possible challenge about this particular solution is that one must invest more money in the designing process. Nonetheless, this money is at least partially regained later in the building´s life when it is disassembled and thus produces valuable reusable material and elements which can be further sold. This is one of the most apparent positive economic effects that building for disassembly has to offer and it shows a clear difference to the current methods where a building is turned into non-profitable waste after it has reached the end of its life.
Another destructive tendency which is strongly present in today’s construction sector is the eagerness for fast financial gains. The project described in this case study aims more for long term cost benefits which in turn can be a problem for some investors who are focused more on quick short-term profits. The designing process which is required for a building to be built for disassembly is at the moment without a doubt costly but like with any other new technology that gradually becomes more widely utilised, the price for this is most likely also bound to decrease.
Moreover, a factor that further increases circularity for this technique is the fact that the walls are built in a way which allows them to be effortlessly moved, thus allowing the shape and size of spaces to be easier altered. This in turn allows the rooms to be effortlessly repurposed, thus increasing the building’s circularity and therefore its lifespan.
Recycling construction materials
Using recycled materials for building is a simple yet effective solution on how to introduce more circularity into construction. The usage of recycled or reused brick wall components as presented in the case study of The Resource Rows was found to reduce the CO2 emissions by 126 tonnes compared to using new bricks. The method of using recycled materials and components offers a more efficient way to upcycle materials which otherwise would end up as waste or landfill.
The benefits of this method are two-sided. Not only does it minimise the amount of new virgin materials and resources extracted, but it also diminishes the waste burden caused on the environment. Especially by decreasing or even removing the need for new raw materials to be extracted, the total CO2 and other emissions produced by the construction process are reduced drastically. The lesser creation of waste benefits the environment by not adding more to the already overloaded landfill sites.
Another interesting and important topic is the cost-benefit ratio of utilising recycled materials versus new ones. Since the materials in the case study have been recycled and upcycled from existing buildings that were bound be demolished anyway, the materials gained were free of costs.
Furthermore, it is also worth noting that, similarly as in the case of designing for disassembly, designing out of recycled materials requires more expertise in the field, and thus more time and money. For example, the planning and designing processes require more calculations and tests concerning the quality of the materials to be used as well as their possible hazardous components. Currently, this forms the number one obstacle that stands in the way of a smoother implementation of recycled goods.
Nonetheless, it is worth mentioning that building out of recycled materials is still a relatively new concept in the construction sector and, again as in the case of designing for disassembly, the current challenges and momentarily high costs can be expected
to be resolved over time as the concept becomes more standardised. The more widespread utilisation of material passports will also offer great assistance in this case.
A fact also worth taking into account is the increasing amount of people willing to invest more money when buying or renting housing if the building in question is constructed using sustainable methods. Especially the younger generation is demanding and expecting increasingly more eco-friendly solutions and features also from their homes.
This is an aspect which needs to be taken into consideration since the building industry, like most industries, depends on the economic profits gained and thus needs to stay up to date with the expectations and demands of their consumers.
Building repurposing
A topic repeatedly stressed in this thesis is the negative impact of the construction sector on environmental health. It is a problem strongly linked to the end of a building´s lifespan, or in other words to the moment of its demolition. This is a challenge that building repurposing is actively trying to change and redirect to a more sustainable course. The two examples presented earlier in this thesis as case studies, the projects of Tempelhof and Tegel airports in Germany, both showcase possible solutions when it comes to modifying a building´s function into something new from what it was initially designed and built for.
As discussed earlier, building repurposing directly decreases the amount of construction waste by removing the need for demolition in order to utilise the surface area consumed by the building. In this way, it also adds circularity to construction by changing old fashioned use-dispose mentality into a more sustainable make-use-reuse one.
Both of the examples presented in the case studies offer valuable information when it comes to the possibilities of building repurposing but nevertheless, it is essential to notice that neither of them provides generalised tools that could effortlessly be implemented also on other types of buildings. Furthermore, since both of the structures presented in the case studies are heritage protected and located in a reasonably wealthy municipality as well as country, Berlin, Germany, they do not offer a realistically comparable solution to other, private or corporate-owned, buildings which are rarely heritage protected and cannot access such an impressive budget for renovations.
Another essential aspect that needs to be taken into consideration before repurposing a building is balancing the following two key elements: structural integrity of the building and its need for renovation or repairments as well as the costs of the imposed project.
If the structural factor is sound, only then is there a chance that the costs of the repurposing will be somehow manageable. This is a fundamental question that always requires attention when it comes to building reutilisation. There is a multitude of empty buildings in the form of factories, old airports, stations and churches that are just waiting to gain a new life. This is a field that is bound to offer great possibilities in the future as soon as it is explored and utilised to its full potential.
Material passport
The final case study presented is related to material passports, and to the possibilities they carry concerning the future of the construction industry. The main advantage is their flexibility since they can be implemented in both new as well as already existing constructions. Their leading role is to optimise the usage of materials that a building has to offer and perceive buildings rather as material banks than dead-ends in a material´s life.
The importance of material passports becomes increasingly evident at the end of a building’s life span. At this moment, with the help of an adequate material passport, the materials included in the building can quickly be evaluated, tracked and extracted to be reused in other constructions. Without a material pass, this is a very complicated procedure, and the majority of materials cannot be adequately identified and reused due to lack of information. The missing information about the existing materials, their amounts and characteristics further complicate the deconstruction process leading to material testing and measurements. These are unnecessary extra steps and costs which can be simply avoided by utilising material passports that already possess all of this critical information. This particular challenge regarding the lack of information on materials was also mentioned earlier when discussing building out of recycled materials, where it formed the number one challenge for the upcycling of goods. This is also a challenge which can be eradicated through the widespread usage of material passports. One might even go so far as to say that material passports form the theoretical centre of sustainability and recycling in construction since they allow the other methods, such as building for disassembly and recycling of materials, to be implemented into practice with much more ease and efficiency.
Finally, it is worth noting that even the concept of material passports is not without its obstacles. Possibly the most significant problem currently is the absence of a joint international database which would allow a more widespread utilisation of materials thus not restricting them to a single country or even a single company. Unfortunately, this has not yet been achieved due to a database of such measures being extremely costly and also requiring proper training of the people updating it. Another potential obstacle slowing down the widespread of material passports is time. The information collected from the buildings needs to be stored for long periods of time, sometimes even decades, until it can be profited from thus decreasing the appeal of the method to some investors. This is also due to the fact that material passports mainly focus on long term financial benefits rather than short term profits.